Merge branch 'master' of https://github.com/serso/android-calculatorpp

android-app/src/main/java/org/solovyev/android/calculator/AndroidNumeralBase.java

@@ -28,8 +28,8 @@ import jscl.NumeralBase;
 import javax.annotation.Nonnull;
 
 import org.solovyev.android.calculator.units.CalculatorNumeralBase;
-import org.solovyev.android.view.drag.DirectionDragButton;
+import org.solovyev.android.calculator.drag.DirectionDragButton;
-import org.solovyev.android.view.drag.DragDirection;
+import org.solovyev.android.calculator.drag.DragDirection;
 
 import java.util.ArrayList;
 import java.util.Arrays;

android-app/src/main/java/org/solovyev/android/calculator/BaseUi.java

@@ -34,13 +34,13 @@ import android.view.MotionEvent;
 import android.view.View;
 import android.widget.TextView;
 import org.solovyev.android.Views;
+import org.solovyev.android.calculator.drag.*;
 import org.solovyev.android.calculator.history.CalculatorHistoryState;
+import org.solovyev.android.calculator.history.HistoryDragProcessor;
 import org.solovyev.android.calculator.view.AngleUnitsButton;
+import org.solovyev.android.calculator.view.DragListenerVibrator;
 import org.solovyev.android.calculator.view.NumeralBasesButton;
-import org.solovyev.android.calculator.view.OnDragListenerVibrator;
 import org.solovyev.android.calculator.view.ViewsCache;
-import org.solovyev.android.history.HistoryDragProcessor;
-import org.solovyev.android.view.drag.*;
 import org.solovyev.common.listeners.JListeners;
 import org.solovyev.common.listeners.Listeners;
 import org.solovyev.common.math.Point2d;
@@ -123,20 +123,21 @@ public abstract class BaseUi implements SharedPreferences.OnSharedPreferenceChan
 		dpclRegister.removeListeners();
 
 		final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(activity);
-		final SimpleOnDragListener.Preferences dragPreferences = SimpleOnDragListener.getPreferences(preferences, activity);
+		final SimpleDragListener.Preferences dragPreferences = SimpleDragListener.getPreferences(preferences, activity);
 
 		final ViewsCache views = ViewsCache.forView(root);
 		setOnDragListeners(views, dragPreferences, preferences);
 
-		final OnDragListener historyOnDragListener = new OnDragListenerVibrator(newOnDragListener(new HistoryDragProcessor<CalculatorHistoryState>(getCalculator()), dragPreferences), vibrator, preferences);
+		HistoryDragProcessor<CalculatorHistoryState> historyDragProcessor = new HistoryDragProcessor<>(getCalculator());
+		final DragListener historyDragListener = new DragListenerVibrator(newOnDragListener(historyDragProcessor, dragPreferences), vibrator, preferences);
 		final DragButton historyButton = getButton(views, R.id.cpp_button_history);
 		if (historyButton != null) {
-			historyButton.setOnDragListener(historyOnDragListener);
+			historyButton.setOnDragListener(historyDragListener);
 		}
 
 		final DragButton subtractionButton = getButton(views, R.id.cpp_button_subtraction);
 		if (subtractionButton != null) {
-			subtractionButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new SimpleOnDragListener.DragProcessor() {
+			subtractionButton.setOnDragListener(new DragListenerVibrator(newOnDragListener(new SimpleDragListener.DragProcessor() {
 				@Override
 				public boolean processDragEvent(@Nonnull DragDirection dragDirection, @Nonnull DragButton dragButton, @Nonnull Point2d startPoint2d, @Nonnull MotionEvent motionEvent) {
 					if (dragDirection == DragDirection.down) {
@@ -148,46 +149,46 @@ public abstract class BaseUi implements SharedPreferences.OnSharedPreferenceChan
 			}, dragPreferences), vibrator, preferences));
 		}
 
-		final OnDragListener toPositionOnDragListener = new OnDragListenerVibrator(new SimpleOnDragListener(new CursorDragProcessor(), dragPreferences), vibrator, preferences);
+		final DragListener toPositionDragListener = new DragListenerVibrator(new SimpleDragListener(new CursorDragProcessor(), dragPreferences), vibrator, preferences);
 
 		final DragButton rightButton = getButton(views, R.id.cpp_button_right);
 		if (rightButton != null) {
-			rightButton.setOnDragListener(toPositionOnDragListener);
+			rightButton.setOnDragListener(toPositionDragListener);
 		}
 
 		final DragButton leftButton = getButton(views, R.id.cpp_button_left);
 		if (leftButton != null) {
-			leftButton.setOnDragListener(toPositionOnDragListener);
+			leftButton.setOnDragListener(toPositionDragListener);
 		}
 
 		final DragButton equalsButton = getButton(views, R.id.cpp_button_equals);
 		if (equalsButton != null) {
-			equalsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new EqualsDragProcessor(), dragPreferences), vibrator, preferences));
+			equalsButton.setOnDragListener(new DragListenerVibrator(newOnDragListener(new EqualsDragProcessor(), dragPreferences), vibrator, preferences));
 		}
 
 		angleUnitsButton = getButton(views, R.id.cpp_button_6);
 		if (angleUnitsButton != null) {
-			angleUnitsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new CalculatorButtons.AngleUnitsChanger(activity), dragPreferences), vibrator, preferences));
+			angleUnitsButton.setOnDragListener(new DragListenerVibrator(newOnDragListener(new CalculatorButtons.AngleUnitsChanger(activity), dragPreferences), vibrator, preferences));
 		}
 
 		clearButton = getButton(views, R.id.cpp_button_clear);
 		if (clearButton != null) {
-			clearButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new CalculatorButtons.NumeralBasesChanger(activity), dragPreferences), vibrator, preferences));
+			clearButton.setOnDragListener(new DragListenerVibrator(newOnDragListener(new CalculatorButtons.NumeralBasesChanger(activity), dragPreferences), vibrator, preferences));
 		}
 
 		final DragButton varsButton = getButton(views, R.id.cpp_button_vars);
 		if (varsButton != null) {
-			varsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new CalculatorButtons.VarsDragProcessor(activity), dragPreferences), vibrator, preferences));
+			varsButton.setOnDragListener(new DragListenerVibrator(newOnDragListener(new CalculatorButtons.VarsDragProcessor(activity), dragPreferences), vibrator, preferences));
 		}
 
 		final DragButton functionsButton = getButton(views, R.id.cpp_button_functions);
 		if (functionsButton != null) {
-			functionsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new CalculatorButtons.FunctionsDragProcessor(activity), dragPreferences), vibrator, preferences));
+			functionsButton.setOnDragListener(new DragListenerVibrator(newOnDragListener(new CalculatorButtons.FunctionsDragProcessor(activity), dragPreferences), vibrator, preferences));
 		}
 
 		final DragButton roundBracketsButton = getButton(views, R.id.cpp_button_round_brackets);
 		if (roundBracketsButton != null) {
-			roundBracketsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new CalculatorButtons.RoundBracketsDragProcessor(), dragPreferences), vibrator, preferences));
+			roundBracketsButton.setOnDragListener(new DragListenerVibrator(newOnDragListener(new CalculatorButtons.RoundBracketsDragProcessor(), dragPreferences), vibrator, preferences));
 		}
 
 		if (layout == simple || layout == simple_mobile) {
@@ -246,14 +247,14 @@ public abstract class BaseUi implements SharedPreferences.OnSharedPreferenceChan
 	}
 
 
-	private void setOnDragListeners(@Nonnull ViewsCache views, @Nonnull SimpleOnDragListener.Preferences dragPreferences, @Nonnull SharedPreferences preferences) {
+	private void setOnDragListeners(@Nonnull ViewsCache views, @Nonnull SimpleDragListener.Preferences dragPreferences, @Nonnull SharedPreferences preferences) {
-		final OnDragListener onDragListener = new OnDragListenerVibrator(newOnDragListener(new DigitButtonDragProcessor(getKeyboard()), dragPreferences), vibrator, preferences);
+		final DragListener dragListener = new DragListenerVibrator(newOnDragListener(new DigitButtonDragProcessor(getKeyboard()), dragPreferences), vibrator, preferences);
 
 		final List<Integer> viewIds = getViewIds();
 		for (Integer viewId : viewIds) {
 			final View view = views.findViewById(viewId);
 			if (view instanceof DragButton) {
-				((DragButton) view).setOnDragListener(onDragListener);
+				((DragButton) view).setOnDragListener(dragListener);
 			}
 		}
 	}
@@ -286,9 +287,9 @@ public abstract class BaseUi implements SharedPreferences.OnSharedPreferenceChan
 	}
 
 	@Nonnull
-	private SimpleOnDragListener newOnDragListener(@Nonnull SimpleOnDragListener.DragProcessor dragProcessor,
+	private SimpleDragListener newOnDragListener(@Nonnull SimpleDragListener.DragProcessor dragProcessor,
-												   @Nonnull SimpleOnDragListener.Preferences dragPreferences) {
+												   @Nonnull SimpleDragListener.Preferences dragPreferences) {
-		final SimpleOnDragListener onDragListener = new SimpleOnDragListener(dragProcessor, dragPreferences);
+		final SimpleDragListener onDragListener = new SimpleDragListener(dragProcessor, dragPreferences);
 		dpclRegister.addListener(onDragListener);
 		return onDragListener;
 	}
@@ -296,7 +297,7 @@ public abstract class BaseUi implements SharedPreferences.OnSharedPreferenceChan
 	@Override
 	public void onSharedPreferenceChanged(SharedPreferences preferences, String key) {
 		if (key.startsWith("org.solovyev.android.calculator.DragButtonCalibrationActivity")) {
-			final SimpleOnDragListener.Preferences dragPreferences = SimpleOnDragListener.getPreferences(preferences, CalculatorApplication.getInstance());
+			final SimpleDragListener.Preferences dragPreferences = SimpleDragListener.getPreferences(preferences, CalculatorApplication.getInstance());
 			for (DragPreferencesChangeListener dragPreferencesChangeListener : dpclRegister.getListeners()) {
 				dragPreferencesChangeListener.onDragPreferencesChange(dragPreferences);
 			}

android-app/src/main/java/org/solovyev/android/calculator/CalculatorButtons.java

@@ -37,13 +37,12 @@ import jscl.AngleUnit;
 import jscl.NumeralBase;
 
 import org.solovyev.android.Views;
-import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.model.AndroidCalculatorEngine;
 import org.solovyev.android.calculator.view.AngleUnitsButton;
 import org.solovyev.android.calculator.view.NumeralBasesButton;
-import org.solovyev.android.view.drag.DragButton;
+import org.solovyev.android.calculator.drag.DragButton;
-import org.solovyev.android.view.drag.DragDirection;
+import org.solovyev.android.calculator.drag.DragDirection;
-import org.solovyev.android.view.drag.SimpleOnDragListener;
+import org.solovyev.android.calculator.drag.SimpleDragListener;
 import org.solovyev.common.math.Point2d;
 
 import javax.annotation.Nonnull;
@@ -118,7 +117,7 @@ public final class CalculatorButtons {
 	**********************************************************************
 	*/
 
-	static class RoundBracketsDragProcessor implements SimpleOnDragListener.DragProcessor {
+	static class RoundBracketsDragProcessor implements SimpleDragListener.DragProcessor {
 		@Override
 		public boolean processDragEvent(@Nonnull DragDirection dragDirection, @Nonnull DragButton dragButton, @Nonnull Point2d startPoint2d, @Nonnull MotionEvent motionEvent) {
 			final boolean result;
@@ -139,7 +138,7 @@ public final class CalculatorButtons {
 		return Locator.getInstance().getKeyboard();
 	}
 
-	static class VarsDragProcessor implements SimpleOnDragListener.DragProcessor {
+	static class VarsDragProcessor implements SimpleDragListener.DragProcessor {
 
 		@Nonnull
 		private Context context;
@@ -167,7 +166,7 @@ public final class CalculatorButtons {
 		}
 	}
 
-	static class AngleUnitsChanger implements SimpleOnDragListener.DragProcessor {
+	static class AngleUnitsChanger implements SimpleDragListener.DragProcessor {
 
 		@Nonnull
 		private final DigitButtonDragProcessor processor;
@@ -216,7 +215,7 @@ public final class CalculatorButtons {
 		}
 	}
 
-	static class NumeralBasesChanger implements SimpleOnDragListener.DragProcessor {
+	static class NumeralBasesChanger implements SimpleDragListener.DragProcessor {
 
 		@Nonnull
 		private final Context context;
@@ -257,7 +256,7 @@ public final class CalculatorButtons {
 		}
 	}
 
-	static class FunctionsDragProcessor implements SimpleOnDragListener.DragProcessor {
+	static class FunctionsDragProcessor implements SimpleDragListener.DragProcessor {
 
 		@Nonnull
 		private Context context;

android-app/src/main/java/org/solovyev/android/calculator/CursorDragProcessor.java

@@ -23,10 +23,10 @@
 package org.solovyev.android.calculator;
 
 import android.view.MotionEvent;
-import org.solovyev.android.view.drag.DirectionDragButton;
+import org.solovyev.android.calculator.drag.DirectionDragButton;
-import org.solovyev.android.view.drag.DragButton;
+import org.solovyev.android.calculator.drag.DragButton;
-import org.solovyev.android.view.drag.DragDirection;
+import org.solovyev.android.calculator.drag.DragDirection;
-import org.solovyev.android.view.drag.SimpleOnDragListener;
+import org.solovyev.android.calculator.drag.SimpleDragListener;
 import org.solovyev.common.math.Point2d;
 
 import javax.annotation.Nonnull;
@@ -36,7 +36,7 @@ import javax.annotation.Nonnull;
  * Date: 9/16/11
  * Time: 11:45 PM
  */
-public class CursorDragProcessor implements SimpleOnDragListener.DragProcessor {
+public class CursorDragProcessor implements SimpleDragListener.DragProcessor {
 
 	public CursorDragProcessor() {
 	}

android-app/src/main/java/org/solovyev/android/calculator/DigitButtonDragProcessor.java

@@ -23,10 +23,10 @@
 package org.solovyev.android.calculator;
 
 import android.view.MotionEvent;
-import org.solovyev.android.view.drag.DirectionDragButton;
+import org.solovyev.android.calculator.drag.DirectionDragButton;
-import org.solovyev.android.view.drag.DragButton;
+import org.solovyev.android.calculator.drag.DragButton;
-import org.solovyev.android.view.drag.DragDirection;
+import org.solovyev.android.calculator.drag.DragDirection;
-import org.solovyev.android.view.drag.SimpleOnDragListener;
+import org.solovyev.android.calculator.drag.SimpleDragListener;
 import org.solovyev.common.math.Point2d;
 
 import javax.annotation.Nonnull;
@@ -36,7 +36,7 @@ import javax.annotation.Nonnull;
  * Date: 9/16/11
  * Time: 11:48 PM
  */
-public class DigitButtonDragProcessor implements SimpleOnDragListener.DragProcessor {
+public class DigitButtonDragProcessor implements SimpleDragListener.DragProcessor {
 
 	@Nonnull
 	private CalculatorKeyboard calculatorKeyboard;

android-app/src/main/java/org/solovyev/android/calculator/EqualsDragProcessor.java

@@ -26,10 +26,10 @@ import android.view.MotionEvent;
 
 import javax.annotation.Nonnull;
 
-import org.solovyev.android.view.drag.DirectionDragButton;
+import org.solovyev.android.calculator.drag.DirectionDragButton;
-import org.solovyev.android.view.drag.DragButton;
+import org.solovyev.android.calculator.drag.DragButton;
-import org.solovyev.android.view.drag.DragDirection;
+import org.solovyev.android.calculator.drag.DragDirection;
-import org.solovyev.android.view.drag.SimpleOnDragListener;
+import org.solovyev.android.calculator.drag.SimpleDragListener;
 import org.solovyev.common.math.Point2d;
 
 /**
@@ -37,7 +37,7 @@ import org.solovyev.common.math.Point2d;
  * Date: 10/24/11
  * Time: 9:52 PM
  */
-public class EqualsDragProcessor implements SimpleOnDragListener.DragProcessor {
+public class EqualsDragProcessor implements SimpleDragListener.DragProcessor {
 
 	public EqualsDragProcessor() {
 	}

android-app/src/main/java/org/solovyev/android/calculator/drag/DirectionDragButton.java

@@ -0,0 +1,411 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.text.TextPaint;
+import android.util.AttributeSet;
+import org.solovyev.common.math.Point2d;
+import org.solovyev.common.text.NumberParser;
+import org.solovyev.common.text.StringCollections;
+import org.solovyev.common.text.Strings;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class DirectionDragButton extends DragButton {
+
+	@Nonnull
+	private final static Float DEFAULT_DIRECTION_TEXT_SCALE_FLOAT = 0.33f;
+
+	@Nonnull
+	private final static Integer DEFAULT_DIRECTION_TEXT_ALPHA = 140;
+
+	private final static int DEFAULT_DIRECTION_TEXT_COLOR = Color.WHITE;
+
+	@Nonnull
+	private final static String DEFAULT_DIRECTION_TEXT_SCALE = "0.33;0.33;0.33;0.33";
+
+	protected static class DirectionTextData {
+
+		@Nonnull
+		private final GuiDragDirection direction;
+
+		@Nonnull
+		private String text;
+
+		@Nonnull
+		private Point2d position;
+
+		@Nonnull
+		private final TextPaint paint = new TextPaint();
+
+		@Nonnull
+		private Float scale = 0.5f;
+
+		private boolean show = true;
+
+		private DirectionTextData(@Nonnull GuiDragDirection direction, @Nonnull String text) {
+			this.direction = direction;
+			this.text = text;
+		}
+
+		protected void init(@Nonnull Paint basePaint,
+							int color,
+							int alpha) {
+			paint.set(basePaint);
+			paint.setColor(color);
+			paint.setAlpha(alpha);
+			paint.setTextSize(basePaint.getTextSize() * scale);
+		}
+
+		@Nonnull
+		public GuiDragDirection getDirection() {
+			return direction;
+		}
+
+		@Nonnull
+		public String getText() {
+			return text;
+		}
+
+		@Nonnull
+		public Point2d getPosition() {
+			return position;
+		}
+
+		@Nonnull
+		public TextPaint getPaint() {
+			return paint;
+		}
+
+		@Nonnull
+		public Float getScale() {
+			return scale;
+		}
+
+		public boolean isShow() {
+			return show;
+		}
+	}
+
+	protected static enum GuiDragDirection {
+		up(DragDirection.up, 0) {
+			@Override
+			public int getAttributeId() {
+				return org.solovyev.android.view.R.styleable.DirectionDragButton_textUp;
+			}
+
+			@Nonnull
+			@Override
+			public Point2d getTextPosition(@Nonnull Paint paint, @Nonnull Paint basePaint, @Nonnull CharSequence text, CharSequence baseText, int w, int h) {
+				return getUpDownTextPosition(paint, basePaint, text, baseText, 1, w, h);
+			}
+		},
+		down(DragDirection.down, 2) {
+			@Override
+			public int getAttributeId() {
+				return org.solovyev.android.view.R.styleable.DirectionDragButton_textDown;
+			}
+
+			@Nonnull
+			@Override
+			public Point2d getTextPosition(@Nonnull Paint paint, @Nonnull Paint basePaint, @Nonnull CharSequence text, CharSequence baseText, int w, int h) {
+				return getUpDownTextPosition(paint, basePaint, text, baseText, -1, w, h);
+			}
+		},
+		left(DragDirection.left, 3) {
+			@Override
+			public int getAttributeId() {
+				return org.solovyev.android.view.R.styleable.DirectionDragButton_textLeft;
+			}
+
+			@Nonnull
+			@Override
+			public Point2d getTextPosition(@Nonnull Paint paint, @Nonnull Paint basePaint, @Nonnull CharSequence text, CharSequence baseText, int w, int h) {
+				return getLeftRightTextPosition(paint, basePaint, text, baseText, w, h, true);
+			}
+		},
+
+		right(DragDirection.right, 1) {
+			@Override
+			public int getAttributeId() {
+				return org.solovyev.android.view.R.styleable.DirectionDragButton_textRight;
+			}
+
+			@Nonnull
+			@Override
+			public Point2d getTextPosition(@Nonnull Paint paint, @Nonnull Paint basePaint, @Nonnull CharSequence text, CharSequence baseText, int w, int h) {
+				return getLeftRightTextPosition(paint, basePaint, text, baseText, w, h, false);
+			}
+		};
+
+		@Nonnull
+		private final DragDirection dragDirection;
+
+		private final int attributePosition;
+
+		GuiDragDirection(@Nonnull DragDirection dragDirection, int attributePosition) {
+			this.dragDirection = dragDirection;
+			this.attributePosition = attributePosition;
+		}
+
+		public abstract int getAttributeId();
+
+		public int getAttributePosition() {
+			return attributePosition;
+		}
+
+		@Nonnull
+		public abstract Point2d getTextPosition(@Nonnull Paint paint, @Nonnull Paint basePaint, @Nonnull CharSequence text, CharSequence baseText, int w, int h);
+
+		@Nonnull
+		private static Point2d getLeftRightTextPosition(@Nonnull Paint paint, @Nonnull Paint basePaint, CharSequence text, @Nonnull CharSequence baseText, int w, int h, boolean left) {
+			final Point2d result = new Point2d();
+
+			if (left) {
+				float width = paint.measureText(" ");
+				result.setX(width);
+			} else {
+				float width = paint.measureText(text.toString() + " ");
+				result.setX(w - width);
+			}
+
+			float selfHeight = paint.ascent() + paint.descent();
+
+			basePaint.measureText(Strings.getNotEmpty(baseText, "|"));
+
+			result.setY(h / 2 - selfHeight / 2);
+
+			return result;
+		}
+
+		@Nonnull
+		private static Point2d getUpDownTextPosition(@Nonnull Paint paint, @Nonnull Paint basePaint, @Nonnull CharSequence text, CharSequence baseText, float direction, int w, int h) {
+			final Point2d result = new Point2d();
+
+			float width = paint.measureText(text.toString() + " ");
+			result.setX(w - width);
+
+			float selfHeight = paint.ascent() + paint.descent();
+
+			basePaint.measureText(Strings.getNotEmpty(baseText, "|"));
+
+			if (direction < 0) {
+				result.setY(h / 2 + h / 3 - selfHeight / 2);
+			} else {
+				result.setY(h / 2 - h / 3 - selfHeight / 2);
+			}
+
+			return result;
+		}
+
+		@Nullable
+		public static GuiDragDirection valueOf(@Nonnull DragDirection dragDirection) {
+			for (GuiDragDirection guiDragDirection : values()) {
+				if (guiDragDirection.dragDirection == dragDirection) {
+					return guiDragDirection;
+				}
+			}
+			return null;
+		}
+	}
+
+	@Nonnull
+	private final Map<GuiDragDirection, DirectionTextData> textDataMap = new EnumMap<GuiDragDirection, DirectionTextData>(GuiDragDirection.class);
+
+	@Nonnull
+	protected String directionTextScale = DEFAULT_DIRECTION_TEXT_SCALE;
+
+	@Nonnull
+	protected Integer directionTextAlpha = DEFAULT_DIRECTION_TEXT_ALPHA;
+
+	protected int directionTextColor = DEFAULT_DIRECTION_TEXT_COLOR;
+
+	private boolean initialized = false;
+
+	public DirectionDragButton(Context context, @Nonnull AttributeSet attrs) {
+		super(context, attrs);
+		init(context, attrs);
+	}
+
+	private void init(@Nonnull Context context, @Nonnull AttributeSet attrs) {
+
+		TypedArray a = context.obtainStyledAttributes(attrs, org.solovyev.android.view.R.styleable.DirectionDragButton);
+
+		for (int i = 0; i < a.getIndexCount(); i++) {
+			int attr = a.getIndex(i);
+
+			if (a.hasValue(attr)) {
+				if (attr == org.solovyev.android.view.R.styleable.DirectionDragButton_directionTextColor) {
+					this.directionTextColor = a.getColor(attr, DEFAULT_DIRECTION_TEXT_COLOR);
+				} else if (attr == org.solovyev.android.view.R.styleable.DirectionDragButton_directionTextScale) {
+					this.directionTextScale = a.getString(attr);
+				} else if (attr == org.solovyev.android.view.R.styleable.DirectionDragButton_directionTextAlpha) {
+					this.directionTextAlpha = a.getInt(attr, DEFAULT_DIRECTION_TEXT_ALPHA);
+				} else {
+					// try drag direction text
+					for (GuiDragDirection guiDragDirection : GuiDragDirection.values()) {
+						if (guiDragDirection.getAttributeId() == attr) {
+							this.textDataMap.put(guiDragDirection, new DirectionTextData(guiDragDirection, a.getString(attr)));
+							break;
+						}
+					}
+				}
+			}
+		}
+
+		a.recycle();
+
+		for (Map.Entry<GuiDragDirection, Float> entry : getDirectionTextScales().entrySet()) {
+			final DirectionTextData td = textDataMap.get(entry.getKey());
+			if (td != null) {
+				td.scale = entry.getValue();
+			}
+		}
+
+		initialized = true;
+	}
+
+	@Override
+	public void onSizeChanged(int w, int h, int oldW, int oldH) {
+		measureText();
+	}
+
+	@Override
+	protected void onTextChanged(CharSequence text, int start, int before, int after) {
+		measureText();
+	}
+
+	protected void measureText() {
+		if (initialized) {
+			final Paint basePaint = getPaint();
+			for (DirectionTextData textData : textDataMap.values()) {
+				initDirectionTextPaint(basePaint, textData);
+				textData.position = textData.direction.getTextPosition(textData.paint, basePaint, textData.text, getText(), getWidth(), getHeight());
+			}
+		}
+	}
+
+	protected void initDirectionTextPaint(@Nonnull Paint basePaint, @Nonnull DirectionTextData textData) {
+		textData.init(basePaint, directionTextColor, directionTextAlpha);
+	}
+
+	@Override
+	public void onDraw(Canvas canvas) {
+		super.onDraw(canvas);
+
+		final TextPaint paint = getPaint();
+		for (DirectionTextData td : textDataMap.values()) {
+			if (td.show) {
+				initDirectionTextPaint(paint, td);
+				final String text = td.text;
+				final Point2d position = td.position;
+				canvas.drawText(text, 0, text.length(), position.getX(), position.getY(), td.paint);
+			}
+		}
+	}
+
+	@SuppressWarnings("UnusedDeclaration")
+	@Nullable
+	public String getTextUp() {
+		return getText(GuiDragDirection.up);
+	}
+
+	@SuppressWarnings("UnusedDeclaration")
+	@Nullable
+	public String getTextDown() {
+		return getText(GuiDragDirection.down);
+	}
+
+	@Nullable
+	public String getText(@Nonnull DragDirection direction) {
+		final GuiDragDirection guiDragDirection = GuiDragDirection.valueOf(direction);
+		return guiDragDirection == null ? null : getText(guiDragDirection);
+	}
+
+	@SuppressWarnings("UnusedDeclaration")
+	public void showDirectionText(boolean show, @Nonnull DragDirection direction) {
+		final GuiDragDirection guiDragDirection = GuiDragDirection.valueOf(direction);
+		final DirectionTextData td = this.textDataMap.get(guiDragDirection);
+		if (td != null) {
+			td.show = show;
+		}
+	}
+
+	@Nullable
+	private String getText(@Nonnull GuiDragDirection direction) {
+		DirectionTextData td = this.textDataMap.get(direction);
+		if (td == null) {
+			return null;
+		} else {
+			if (td.show) {
+				return td.text;
+			} else {
+				return null;
+			}
+		}
+	}
+
+
+	@Nonnull
+	public String getDirectionTextScale() {
+		return directionTextScale;
+	}
+
+	@Nonnull
+	private Map<GuiDragDirection, Float> getDirectionTextScales() {
+		final List<Float> scales = StringCollections.split(getDirectionTextScale(), ";", NumberParser.of(Float.class));
+
+		final Map<GuiDragDirection, Float> result = new HashMap<GuiDragDirection, Float>();
+		for (GuiDragDirection direction : GuiDragDirection.values()) {
+			result.put(direction, DEFAULT_DIRECTION_TEXT_SCALE_FLOAT);
+		}
+
+		if (scales.size() == 1) {
+			final Float scale = scales.get(0);
+			for (Map.Entry<GuiDragDirection, Float> entry : result.entrySet()) {
+				entry.setValue(scale);
+			}
+		} else {
+			for (int i = 0; i < scales.size(); i++) {
+				for (GuiDragDirection direction : GuiDragDirection.values()) {
+					if (direction.getAttributePosition() == i) {
+						result.put(direction, scales.get(i));
+					}
+				}
+			}
+		}
+
+		return result;
+	}
+
+}

android-app/src/main/java/org/solovyev/android/calculator/drag/DragButton.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.MotionEvent;
+import android.widget.Button;
+import org.solovyev.android.view.AndroidViewUtils;
+import org.solovyev.common.math.Point2d;
+import org.solovyev.common.text.Strings;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+public class DragButton extends Button {
+
+	@Nullable
+	private Point2d startPoint = null;
+
+	@Nullable
+	private DragListener onDragListener;
+
+	private boolean showText = true;
+
+	@Nullable
+	private CharSequence textBackup;
+
+	public DragButton(@Nonnull Context context, @Nonnull AttributeSet attrs) {
+		super(context, attrs);
+	}
+
+	public void setOnDragListener(@Nullable DragListener onDragListener) {
+		this.onDragListener = onDragListener;
+	}
+
+	@Override
+	public boolean onTouchEvent(@Nonnull MotionEvent event) {
+		boolean consumed = false;
+
+		// in order to avoid possible NPEs
+		final Point2d localStartPoint = startPoint;
+		final DragListener localOnDragListener = onDragListener;
+
+		if (localOnDragListener != null) {
+			// only if onDrag() listener specified
+
+			Log.d(String.valueOf(getId()), "onTouch() for: " + getId() + " . Motion event: " + event);
+
+			switch (event.getAction()) {
+				case MotionEvent.ACTION_DOWN:
+					// start tracking: set start point
+					startPoint = new Point2d(event.getX(), event.getY());
+					break;
+
+				case MotionEvent.ACTION_CANCEL:
+				case MotionEvent.ACTION_UP:
+					// stop tracking
+
+					startPoint = null;
+					if (localStartPoint != null) {
+						consumed = localOnDragListener.onDrag(DragButton.this, new DragEvent(localStartPoint, event));
+						if (consumed && localOnDragListener.isSuppressOnClickEvent()) {
+							final MotionEvent newEvent = MotionEvent.obtain(event);
+							newEvent.setAction(MotionEvent.ACTION_CANCEL);
+							super.onTouchEvent(newEvent);
+							newEvent.recycle();
+							return true;
+						}
+					}
+					break;
+			}
+		}
+
+		return super.onTouchEvent(event) || consumed;
+	}
+
+	@Override
+	public boolean dispatchTouchEvent(@Nonnull MotionEvent event) {
+		return super.dispatchTouchEvent(event);
+	}
+
+	@Override
+	protected void onDraw(Canvas canvas) {
+		CharSequence text = getText();
+		if (!Strings.isEmpty(text)) {
+			super.onDraw(canvas);
+		} else {
+			if (!AndroidViewUtils.drawDrawables(canvas, this)) {
+				super.onDraw(canvas);
+			}
+		}
+	}
+
+
+	public boolean isShowText() {
+		return showText;
+	}
+
+	public void setShowText(boolean showText) {
+		if (this.showText != showText) {
+			if (showText) {
+				setText(textBackup);
+				textBackup = null;
+			} else {
+				textBackup = this.getText();
+				setText(null);
+			}
+			this.showText = showText;
+		}
+	}
+}

android-app/src/main/java/org/solovyev/android/calculator/drag/DragDirection.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+public enum DragDirection {
+
+	up,
+	down,
+	left,
+	right;
+}

android-app/src/main/java/org/solovyev/android/calculator/drag/DragEvent.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+import android.view.MotionEvent;
+import org.solovyev.common.math.Point2d;
+
+import javax.annotation.Nonnull;
+
+public class DragEvent {
+
+	@Nonnull
+	private final Point2d startPoint;
+
+	@Nonnull
+	private final MotionEvent motionEvent;
+
+	public DragEvent(@Nonnull Point2d startPoint, @Nonnull MotionEvent motionEvent) {
+		this.startPoint = startPoint;
+		this.motionEvent = motionEvent;
+	}
+
+	/**
+	 * @return motion event started at start point
+	 */
+	@Nonnull
+	public MotionEvent getMotionEvent() {
+		return motionEvent;
+	}
+
+	/**
+	 * @return start point of dragging
+	 */
+	@Nonnull
+	public Point2d getStartPoint() {
+		return startPoint;
+	}
+
+
+}

android-app/src/main/java/org/solovyev/android/calculator/drag/DragListener.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+import javax.annotation.Nonnull;
+import java.util.EventListener;
+
+
+public interface DragListener extends EventListener {
+
+	/**
+	 * @return 'true': if drag event has taken place (i.e. onDrag() method returned true) then click action will be suppresed
+	 */
+	boolean isSuppressOnClickEvent();
+
+	/**
+	 * @param dragButton drag button object for which onDrag listener was set
+	 * @param event      drag event
+	 * @return 'true' if drag event occurred, 'false' otherwise
+	 */
+	boolean onDrag(@Nonnull DragButton dragButton, @Nonnull DragEvent event);
+
+}

android-app/src/main/java/org/solovyev/android/calculator/drag/DragListenerWrapper.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+import javax.annotation.Nonnull;
+
+/**
+ * User: serso
+ * Date: 10/26/11
+ * Time: 10:37 PM
+ */
+public class DragListenerWrapper implements DragListener {
+
+	@Nonnull
+	private final DragListener dragListener;
+
+	public DragListenerWrapper(@Nonnull DragListener dragListener) {
+		this.dragListener = dragListener;
+	}
+
+	@Override
+	public boolean isSuppressOnClickEvent() {
+		return this.dragListener.isSuppressOnClickEvent();
+	}
+
+	@Override
+	public boolean onDrag(@Nonnull DragButton dragButton, @Nonnull DragEvent event) {
+		return this.dragListener.onDrag(dragButton, event);
+	}
+}

android-app/src/main/java/org/solovyev/android/calculator/drag/DragPreferencesChangeListener.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+import javax.annotation.Nonnull;
+import java.util.EventListener;
+
+/**
+ * User: serso
+ * Date: 9/18/11
+ * Time: 8:48 PM
+ */
+public interface DragPreferencesChangeListener extends EventListener {
+
+	void onDragPreferencesChange(@Nonnull SimpleDragListener.Preferences preferences);
+}

android-app/src/main/java/org/solovyev/android/calculator/drag/SimpleDragListener.java

@@ -0,0 +1,295 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.drag;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.util.Log;
+import android.view.MotionEvent;
+import org.solovyev.common.MutableObject;
+import org.solovyev.common.interval.Interval;
+import org.solovyev.common.interval.Intervals;
+import org.solovyev.common.math.Maths;
+import org.solovyev.common.math.Point2d;
+import org.solovyev.common.text.Mapper;
+import org.solovyev.common.text.NumberIntervalMapper;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.util.HashMap;
+import java.util.Map;
+
+public class SimpleDragListener implements DragListener, DragPreferencesChangeListener {
+
+	@Nonnull
+	public static final Point2d axis = new Point2d(0, 1);
+
+	@Nonnull
+	private DragProcessor dragProcessor;
+
+	@Nonnull
+	private Preferences preferences;
+
+	public SimpleDragListener(@Nonnull DragProcessor dragProcessor, @Nonnull Preferences preferences) {
+		this.dragProcessor = dragProcessor;
+		this.preferences = preferences;
+	}
+
+	@Override
+	public boolean onDrag(@Nonnull DragButton dragButton, @Nonnull DragEvent event) {
+		boolean result = false;
+
+		logDragEvent(dragButton, event);
+
+		final Point2d startPoint = event.getStartPoint();
+		final MotionEvent motionEvent = event.getMotionEvent();
+
+		// init end point
+		final Point2d endPoint = new Point2d(motionEvent.getX(), motionEvent.getY());
+
+		final float distance = Maths.getDistance(startPoint, endPoint);
+
+		final MutableObject<Boolean> right = new MutableObject<Boolean>();
+		final double angle = Math.toDegrees(Maths.getAngle(startPoint, Maths.sum(startPoint, axis), endPoint, right));
+		Log.d(String.valueOf(dragButton.getId()), "Angle: " + angle);
+		Log.d(String.valueOf(dragButton.getId()), "Is right?: " + right.getObject());
+
+		final double duration = motionEvent.getEventTime() - motionEvent.getDownTime();
+
+		final Preference distancePreferences = preferences.getPreferencesMap().get(PreferenceType.distance);
+		final Preference anglePreferences = preferences.getPreferencesMap().get(PreferenceType.angle);
+
+		DragDirection direction = null;
+		for (Map.Entry<DragDirection, DragPreference> directionEntry : distancePreferences.getDirectionPreferences().entrySet()) {
+
+			Log.d(String.valueOf(dragButton.getId()), "Drag direction: " + directionEntry.getKey());
+			Log.d(String.valueOf(dragButton.getId()), "Trying direction interval: " + directionEntry.getValue().getInterval());
+
+			if (directionEntry.getValue().getInterval().contains(distance)) {
+				final DragPreference anglePreference = anglePreferences.getDirectionPreferences().get(directionEntry.getKey());
+
+				Log.d(String.valueOf(dragButton.getId()), "Trying angle interval: " + anglePreference.getInterval());
+
+				if (directionEntry.getKey() == DragDirection.left && right.getObject()) {
+				} else if (directionEntry.getKey() == DragDirection.right && !right.getObject()) {
+				} else {
+					if (anglePreference.getInterval().contains((float) angle)) {
+						direction = directionEntry.getKey();
+						Log.d(String.valueOf(dragButton.getId()), "MATCH! Direction: " + direction);
+						break;
+					}
+				}
+			}
+
+		}
+
+		if (direction != null) {
+			final Preference durationPreferences = preferences.getPreferencesMap().get(PreferenceType.duration);
+
+			final DragPreference durationDragPreferences = durationPreferences.getDirectionPreferences().get(direction);
+
+			Log.d(String.valueOf(dragButton.getId()), "Trying time interval: " + durationDragPreferences.getInterval());
+			if (durationDragPreferences.getInterval().contains((float) duration)) {
+				Log.d(String.valueOf(dragButton.getId()), "MATCH!");
+				result = dragProcessor.processDragEvent(direction, dragButton, startPoint, motionEvent);
+			}
+		}
+
+		return result;
+	}
+
+	@Override
+	public boolean isSuppressOnClickEvent() {
+		return true;
+	}
+
+	private void logDragEvent(@Nonnull DragButton dragButton, @Nonnull DragEvent event) {
+		final Point2d startPoint = event.getStartPoint();
+		final MotionEvent motionEvent = event.getMotionEvent();
+		final Point2d endPoint = new Point2d(motionEvent.getX(), motionEvent.getY());
+
+		Log.d(String.valueOf(dragButton.getId()), "Start point: " + startPoint + ", End point: " + endPoint);
+		Log.d(String.valueOf(dragButton.getId()), "Distance: " + Maths.getDistance(startPoint, endPoint));
+		final MutableObject<Boolean> right = new MutableObject<Boolean>();
+		Log.d(String.valueOf(dragButton.getId()), "Angle: " + Math.toDegrees(Maths.getAngle(startPoint, Maths.sum(startPoint, axis), endPoint, right)));
+		Log.d(String.valueOf(dragButton.getId()), "Is right angle? " + right);
+		Log.d(String.valueOf(dragButton.getId()), "Axis: " + axis + " Vector: " + Maths.subtract(endPoint, startPoint));
+		Log.d(String.valueOf(dragButton.getId()), "Total time: " + (motionEvent.getEventTime() - motionEvent.getDownTime()) + " ms");
+	}
+
+	@Override
+	public void onDragPreferencesChange(@Nonnull Preferences preferences) {
+		this.preferences = preferences;
+	}
+
+	public interface DragProcessor {
+
+		boolean processDragEvent(@Nonnull DragDirection dragDirection, @Nonnull DragButton dragButton, @Nonnull Point2d startPoint2d, @Nonnull MotionEvent motionEvent);
+	}
+
+	// todo serso: currently we do not use direction
+	public static String getPreferenceId(@Nonnull PreferenceType preferenceType, @Nonnull DragDirection direction) {
+		return "org.solovyev.android.calculator.DragButtonCalibrationActivity" + "_" + preferenceType.name() /*+ "_" + direction.name()*/;
+	}
+
+	@Nonnull
+	public static Preferences getDefaultPreferences(@Nonnull Context context) {
+		return getPreferences0(null, context);
+	}
+
+	@Nonnull
+	public static Preferences getPreferences(@Nonnull final SharedPreferences preferences, @Nonnull Context context) {
+		return getPreferences0(preferences, context);
+	}
+
+	@Nonnull
+	private static Preferences getPreferences0(@Nullable final SharedPreferences preferences, @Nonnull Context context) {
+
+		final Mapper<Interval<Float>> mapper = NumberIntervalMapper.of(Float.class);
+
+		final Preferences result = new Preferences();
+
+		for (PreferenceType preferenceType : PreferenceType.values()) {
+			for (DragDirection dragDirection : DragDirection.values()) {
+
+				final String preferenceId = getPreferenceId(preferenceType, dragDirection);
+
+				final String defaultValue;
+				switch (preferenceType) {
+					case angle:
+						defaultValue = context.getResources().getString(org.solovyev.android.view.R.string.p_drag_angle);
+						break;
+					case distance:
+						defaultValue = context.getResources().getString(org.solovyev.android.view.R.string.p_drag_distance);
+						break;
+					case duration:
+						defaultValue = context.getResources().getString(org.solovyev.android.view.R.string.p_drag_duration);
+						break;
+					default:
+						defaultValue = null;
+						Log.e(SimpleDragListener.class.getName(), "New preference type added: default preferences should be defined. Preference id: " + preferenceId);
+				}
+
+				final String value = preferences == null ? defaultValue : preferences.getString(preferenceId, defaultValue);
+
+				if (value != null) {
+					final Interval<Float> intervalPref = transformInterval(preferenceType, dragDirection, mapper.parseValue(value));
+
+					Log.d(SimpleDragListener.class.getName(), "Preference loaded for " + dragDirection + ". Id: " + preferenceId + ", value: " + intervalPref.toString());
+
+					final DragPreference directionPreference = new DragPreference(intervalPref);
+
+					Preference preference = result.getPreferencesMap().get(preferenceType);
+					if (preference == null) {
+						preference = new Preference();
+						result.getPreferencesMap().put(preferenceType, preference);
+					}
+
+					preference.getDirectionPreferences().put(dragDirection, directionPreference);
+				}
+			}
+		}
+
+		return result;
+	}
+
+	@Nonnull
+	public static Interval<Float> transformInterval(@Nonnull PreferenceType preferenceType,
+													@Nonnull DragDirection dragDirection,
+													@Nonnull Interval<Float> interval) {
+
+		if (preferenceType == PreferenceType.angle) {
+			final Float leftLimit = interval.getLeftLimit();
+			final Float rightLimit = interval.getRightLimit();
+
+			if (leftLimit != null && rightLimit != null) {
+				final Float newLeftLimit;
+				final Float newRightLimit;
+
+				if (dragDirection == DragDirection.up) {
+					newLeftLimit = 180f - rightLimit;
+					newRightLimit = 180f - leftLimit;
+				} else if (dragDirection == DragDirection.left) {
+					newLeftLimit = 90f - rightLimit;
+					newRightLimit = 90f + rightLimit;
+				} else if (dragDirection == DragDirection.right) {
+					newLeftLimit = 90f - rightLimit;
+					newRightLimit = 90f + rightLimit;
+				} else {
+					newLeftLimit = leftLimit;
+					newRightLimit = rightLimit;
+				}
+
+				return Intervals.newClosedInterval(newLeftLimit, newRightLimit);
+			}
+		}
+
+		return interval;
+	}
+
+
+	public static enum PreferenceType {
+		angle,
+		distance,
+		duration
+	}
+
+	public static class DragPreference {
+
+		@Nonnull
+		private Interval<Float> interval;
+
+
+		public DragPreference(@Nonnull Interval<Float> interval) {
+			this.interval = interval;
+		}
+
+		@Nonnull
+		public Interval<Float> getInterval() {
+			return interval;
+		}
+
+	}
+
+	public static class Preference {
+
+		@Nonnull
+		private Map<DragDirection, DragPreference> directionPreferences = new HashMap<DragDirection, DragPreference>();
+
+
+		@Nonnull
+		public Map<DragDirection, DragPreference> getDirectionPreferences() {
+			return directionPreferences;
+		}
+
+	}
+
+	public static class Preferences {
+
+		private final Map<PreferenceType, Preference> preferencesMap = new HashMap<>();
+
+		public Map<PreferenceType, Preference> getPreferencesMap() {
+			return preferencesMap;
+		}
+	}
+}

android-app/src/main/java/org/solovyev/android/calculator/history/HistoryDragProcessor.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2013 serso aka se.solovyev
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Contact details
+ *
+ * Email: se.solovyev@gmail.com
+ * Site:  http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.history;
+
+import android.util.Log;
+import android.view.MotionEvent;
+import org.solovyev.android.calculator.drag.DragButton;
+import org.solovyev.android.calculator.drag.DragDirection;
+import org.solovyev.android.calculator.drag.SimpleDragListener;
+import org.solovyev.common.history.HistoryAction;
+import org.solovyev.common.history.HistoryControl;
+import org.solovyev.common.math.Point2d;
+
+import javax.annotation.Nonnull;
+
+/**
+ * User: serso
+ * Date: 9/16/11
+ * Time: 11:36 PM
+ */
+public class HistoryDragProcessor<T> implements SimpleDragListener.DragProcessor {
+
+	@Nonnull
+	private final HistoryControl<T> historyControl;
+
+	public HistoryDragProcessor(@Nonnull HistoryControl<T> historyControl) {
+		this.historyControl = historyControl;
+	}
+
+	@Override
+	public boolean processDragEvent(@Nonnull DragDirection dragDirection, @Nonnull DragButton dragButton, @Nonnull Point2d startPoint2d, @Nonnull MotionEvent motionEvent) {
+		boolean result = false;
+
+		Log.d(String.valueOf(dragButton.getId()), "History on drag event start: " + dragDirection);
+
+		final HistoryAction historyAction;
+		if (dragDirection == DragDirection.up) {
+			historyAction = HistoryAction.undo;
+		} else if (dragDirection == DragDirection.down) {
+			historyAction = HistoryAction.redo;
+		} else {
+			historyAction = null;
+		}
+
+		if (historyAction != null) {
+			result = true;
+			historyControl.doHistoryAction(historyAction);
+		}
+
+		return result;
+	}
+}

android-app/src/main/java/org/solovyev/android/calculator/preferences/BasePreferencesActivity.java

@@ -9,6 +9,7 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.LinearLayout;
+import android.widget.ListView;
 import org.solovyev.android.calculator.ActivityUi;
 import org.solovyev.android.calculator.AdView;
 import org.solovyev.android.calculator.App;
@@ -22,6 +23,7 @@ import javax.annotation.Nonnull;
 
 public abstract class BasePreferencesActivity extends PreferenceActivity {
 
+	private static boolean SUPPORT_HEADERS = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB;
 	private final ActivityCheckout checkout = Checkout.forActivity(this, App.getBilling(), App.getProducts());
 	private Inventory inventory;
 	private AdView adView;
@@ -66,29 +68,37 @@ public abstract class BasePreferencesActivity extends PreferenceActivity {
 	}
 
 	protected void onShowAd(boolean show) {
-		if(!supportsAds()) {
+		if (!supportsHeaders()) {
 			return;
 		}
+
+		final ListView listView = getListView();
 		if (show) {
 			if (adView != null) {
 				return;
 			}
 			adView = (AdView) LayoutInflater.from(this).inflate(R.layout.ad, null);
 			adView.show();
-			getListView().addHeaderView(adView);
+			try {
+				listView.addHeaderView(adView);
+			} catch (IllegalStateException e) {
+				// doesn't support header views
+				SUPPORT_HEADERS = false;
+				adView.hide();
+				adView = null;
+			}
 		} else {
 			if (adView == null) {
 				return;
 			}
-			getListView().removeHeaderView(adView);
+			listView.removeHeaderView(adView);
 			adView.hide();
 			adView = null;
 		}
 	}
 
-	private boolean supportsAds() {
+	private boolean supportsHeaders() {
-		// on Android 2.3 the headers in the list view are not supported
+		return SUPPORT_HEADERS;
-		return Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB;
 	}
 
 	@Override

android-app/src/main/java/org/solovyev/android/calculator/view/AngleUnitsButton.java

@@ -30,7 +30,7 @@ import android.util.AttributeSet;
 import jscl.AngleUnit;
 import org.solovyev.android.calculator.Locator;
 import org.solovyev.android.calculator.R;
-import org.solovyev.android.view.drag.DirectionDragButton;
+import org.solovyev.android.calculator.drag.DirectionDragButton;
 
 import javax.annotation.Nonnull;
 

android-app/src/main/java/org/solovyev/android/calculator/view/DragListenerVibrator.java

@@ -24,36 +24,36 @@ package org.solovyev.android.calculator.view;
 
 import android.content.SharedPreferences;
 import android.os.Vibrator;
+import org.solovyev.android.calculator.drag.DragButton;
+import org.solovyev.android.calculator.drag.DragEvent;
+import org.solovyev.android.calculator.drag.DragListener;
+import org.solovyev.android.calculator.drag.DragListenerWrapper;
+import org.solovyev.android.view.VibratorContainer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
-import org.solovyev.android.view.VibratorContainer;
-import org.solovyev.android.view.drag.DragButton;
-import org.solovyev.android.view.drag.OnDragListener;
-import org.solovyev.android.view.drag.OnDragListenerWrapper;
-
 /**
  * User: serso
  * Date: 4/20/12
  * Time: 3:27 PM
  */
-public class OnDragListenerVibrator extends OnDragListenerWrapper {
+public class DragListenerVibrator extends DragListenerWrapper {
 
 	private static final float VIBRATION_TIME_SCALE = 0.5f;
 
 	@Nonnull
 	private final VibratorContainer vibrator;
 
-	public OnDragListenerVibrator(@Nonnull OnDragListener onDragListener,
+	public DragListenerVibrator(@Nonnull DragListener dragListener,
 								@Nullable Vibrator vibrator,
 								@Nonnull SharedPreferences preferences) {
-		super(onDragListener);
+		super(dragListener);
 		this.vibrator = new VibratorContainer(vibrator, preferences, VIBRATION_TIME_SCALE);
 	}
 
 	@Override
-	public boolean onDrag(@Nonnull DragButton dragButton, @Nonnull org.solovyev.android.view.drag.DragEvent event) {
+	public boolean onDrag(@Nonnull DragButton dragButton, @Nonnull DragEvent event) {
 		boolean result = super.onDrag(dragButton, event);
 
 		if (result) {

android-app/src/main/java/org/solovyev/android/calculator/view/NumeralBasesButton.java

@@ -29,7 +29,7 @@ import android.util.AttributeSet;
 import jscl.NumeralBase;
 import org.solovyev.android.calculator.Locator;
 import org.solovyev.android.calculator.R;
-import org.solovyev.android.view.drag.DirectionDragButton;
+import org.solovyev.android.calculator.drag.DirectionDragButton;
 
 import javax.annotation.Nonnull;
 

android-app/src/main/java/org/solovyev/android/calculator/wizard/DragButtonWizardStep.java

@@ -23,16 +23,14 @@
 package org.solovyev.android.calculator.wizard;
 
 import android.os.Bundle;
-import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
-import android.view.ViewGroup;
 import android.widget.TextView;
 import org.solovyev.android.calculator.R;
-import org.solovyev.android.view.drag.DirectionDragButton;
+import org.solovyev.android.calculator.drag.DirectionDragButton;
-import org.solovyev.android.view.drag.DragButton;
+import org.solovyev.android.calculator.drag.DragButton;
-import org.solovyev.android.view.drag.DragDirection;
+import org.solovyev.android.calculator.drag.DragDirection;
-import org.solovyev.android.view.drag.SimpleOnDragListener;
+import org.solovyev.android.calculator.drag.SimpleDragListener;
 import org.solovyev.common.math.Point2d;
 
 import javax.annotation.Nonnull;
@@ -86,7 +84,7 @@ public class DragButtonWizardStep extends WizardFragment {
 
 		dragButton = (DirectionDragButton) root.findViewById(R.id.wizard_dragbutton);
 		dragButton.setOnClickListener(new DragButtonOnClickListener());
-		dragButton.setOnDragListener(new SimpleOnDragListener(new DragButtonProcessor(), SimpleOnDragListener.getDefaultPreferences(getActivity())));
+		dragButton.setOnDragListener(new SimpleDragListener(new DragButtonProcessor(), SimpleDragListener.getDefaultPreferences(getActivity())));
 		actionTextView = (TextView) root.findViewById(R.id.wizard_dragbutton_action_textview);
 		descriptionTextView = (TextView) root.findViewById(R.id.wizard_dragbutton_description_textview);
 
@@ -151,7 +149,7 @@ public class DragButtonWizardStep extends WizardFragment {
 		setAction(action.getNextAction());
 	}
 
-	private class DragButtonProcessor implements SimpleOnDragListener.DragProcessor {
+	private class DragButtonProcessor implements SimpleDragListener.DragProcessor {
 		@Override
 		public boolean processDragEvent(@Nonnull DragDirection dragDirection,
 										@Nonnull DragButton dragButton,

android-app/src/main/res/layout/cpp_drag_button_0.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_0"
 													c:textUp="00"

android-app/src/main/res/layout/cpp_drag_button_1.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_1"
 													a:text="1"

android-app/src/main/res/layout/cpp_drag_button_2.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_2"
 													a:text="2"

android-app/src/main/res/layout/cpp_drag_button_3.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_3"
 													a:text="3"

android-app/src/main/res/layout/cpp_drag_button_4.xml

@@ -21,7 +21,7 @@
   ~ Email: se.solovyev@gmail.com
   ~ Site:  http://se.solovyev.org
   -->
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_4"
 													a:text="4"

android-app/src/main/res/layout/cpp_drag_button_5.xml

@@ -21,7 +21,7 @@
   ~ Email: se.solovyev@gmail.com
   ~ Site:  http://se.solovyev.org
   -->
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_5"
 													a:text="5"

android-app/src/main/res/layout/cpp_drag_button_7.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_7"
 													a:text="7"

android-app/src/main/res/layout/cpp_drag_button_8.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_8"
 													a:text="8"

android-app/src/main/res/layout/cpp_drag_button_9.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_9"
 													a:text="9"

android-app/src/main/res/layout/cpp_drag_button_division.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_division"
 													c:textUp="%"

android-app/src/main/res/layout/cpp_drag_button_dot.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_period"
 													a:text="."

android-app/src/main/res/layout/cpp_drag_button_empty.xml

@@ -21,4 +21,4 @@
   ~ Email: se.solovyev@gmail.com
   ~ Site:  http://se.solovyev.org
   -->
-<org.solovyev.android.view.drag.DirectionDragButton style="?cpp_control_button_style"/>
+<org.solovyev.android.calculator.drag.DirectionDragButton style="?cpp_control_button_style"/>

android-app/src/main/res/layout/cpp_drag_button_equals.xml

@@ -21,7 +21,7 @@
   ~ Email: se.solovyev@gmail.com
   ~ Site:  http://se.solovyev.org
   -->
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_equals"
 													c:textUp="≡"

android-app/src/main/res/layout/cpp_drag_button_functions.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_functions"
 													c:directionTextScale="0.5"

android-app/src/main/res/layout/cpp_drag_button_history.xml

@@ -21,7 +21,7 @@
   ~ Email: se.solovyev@gmail.com
   ~ Site:  http://se.solovyev.org
   -->
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_history"
 													a:text="@string/c_history_button"

android-app/src/main/res/layout/cpp_drag_button_left.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_left"
 													c:textUp="◁◁"

android-app/src/main/res/layout/cpp_drag_button_multiplication.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_multiplication"
 													a:text="×"

android-app/src/main/res/layout/cpp_drag_button_operators.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													a:id="@id/cpp_button_operators"
 													a:text="∂,…"
 													a:onClick="operatorsButtonClickHandler"

android-app/src/main/res/layout/cpp_drag_button_plus.xml

@@ -21,7 +21,7 @@
   ~ Email: se.solovyev@gmail.com
   ~ Site:  http://se.solovyev.org
   -->
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_plus"
 													c:directionTextScale="0.5"

android-app/src/main/res/layout/cpp_drag_button_right.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_right"
 													c:textUp="▷▷"

android-app/src/main/res/layout/cpp_drag_button_round_brackets.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_round_brackets"
 													c:textUp="("

android-app/src/main/res/layout/cpp_drag_button_subtraction.xml

@@ -21,7 +21,7 @@
   ~ Email: se.solovyev@gmail.com
   ~ Site:  http://se.solovyev.org
   -->
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_subtraction"
 													c:textDown="∂,…"

android-app/src/main/res/layout/cpp_drag_button_vars.xml

@@ -22,7 +22,7 @@
   ~ Site:  http://se.solovyev.org
   -->
 
-<org.solovyev.android.view.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
+<org.solovyev.android.calculator.drag.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													xmlns:c="http://schemas.android.com/apk/res-auto"
 													a:id="@id/cpp_button_vars"
 													c:directionTextScale="0.5"

android-app/src/main/res/layout/cpp_wizard_step_drag_button.xml

@@ -42,7 +42,7 @@
 		a:minLines="3"
 		a:maxLines="3"/>
 
-	<org.solovyev.android.view.drag.DirectionDragButton
+	<org.solovyev.android.calculator.drag.DirectionDragButton
 		a:layout_margin="0dp"
 		a:layout_height="wrap_content"
 		a:layout_width="wrap_content"

android-app/src/main/res/layout/drag_button_calibration.xml

@@ -47,7 +47,7 @@
 					a:layout_width="80dp"
 					a:layout_height="80dp"/>
 
-			<org.solovyev.android.view.drag.DirectionDragButton
+			<org.solovyev.android.calculator.drag.DirectionDragButton
 					a:id="@+id/calibrationButtonLeft"
 					a:text=""
 					c:textUp="@string/c_up"
@@ -56,7 +56,7 @@
 					a:layout_height="80dp"
 					style="?cpp_digit_button_style"/>
 
-			<org.solovyev.android.view.drag.DirectionDragButton
+			<org.solovyev.android.calculator.drag.DirectionDragButton
 					a:id="@+id/calibrationButtonRight"
 					a:text=""
 					c:textUp="@string/c_up"