separating application

AndroidManifest.xml

@@ -13,9 +13,9 @@
 
 	<application a:icon="@drawable/icon"
 				 a:label="@string/c_app_name"
-				 a:name=".ApplicationContext">
+				 a:name="org.solovyev.android.calculator.ApplicationContext">
 
-		<activity a:name=".CalculatorActivity"
+		<activity a:name="org.solovyev.android.calculator.CalculatorActivityFree"
 				  a:label="@string/c_app_name">
 
 			<intent-filter>
@@ -25,71 +25,71 @@
 
 		</activity>
 
-		<activity a:name=".CalculatorPreferencesActivity"
+		<activity a:name="org.solovyev.android.calculator.CalculatorPreferencesActivity"
 				  a:label="@string/c_app_settings"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".history.CalculatorHistoryActivity"
+		<activity a:name="org.solovyev.android.calculator.history.CalculatorHistoryActivity"
 				  a:label="@string/c_app_history"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-	   	<activity a:name=".history.HistoryActivityTab"
+	   	<activity a:name="org.solovyev.android.calculator.history.HistoryActivityTab"
 				  a:label="@string/c_history"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".history.SavedHistoryActivityTab"
+		<activity a:name="org.solovyev.android.calculator.history.SavedHistoryActivityTab"
 				  a:label="@string/c_saved_history"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".about.CalculatorAboutTabActivity"
+		<activity a:name="org.solovyev.android.calculator.about.CalculatorAboutTabActivity"
 				  a:label="@string/c_about"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".about.CalculatorAboutActivity"
+		<activity a:name="org.solovyev.android.calculator.about.CalculatorAboutActivity"
 				  a:label="@string/c_about"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".about.CalculatorReleaseNotesActivity"
+		<activity a:name="org.solovyev.android.calculator.about.CalculatorReleaseNotesActivity"
 				  a:label="@string/c_about"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".help.CalculatorHelpTabActivity"
+		<activity a:name="org.solovyev.android.calculator.help.CalculatorHelpTabActivity"
 				  a:label="@string/c_help"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".help.HelpFaqActivity"
+		<activity a:name="org.solovyev.android.calculator.help.HelpFaqActivity"
 				  a:label="@string/c_help"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".help.HelpHintsActivity"
+		<activity a:name="org.solovyev.android.calculator.help.HelpHintsActivity"
 				  a:label="@string/c_help"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".help.HelpScreensActivity"
+		<activity a:name="org.solovyev.android.calculator.help.HelpScreensActivity"
 				  a:label="@string/c_help"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-        <activity a:name=".math.edit.CalculatorFunctionsActivity"
+        <activity a:name="org.solovyev.android.calculator.math.edit.CalculatorFunctionsActivity"
                   a:label="@string/c_functions"
                   a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".math.edit.CalculatorFunctionsTabActivity"
+		<activity a:name="org.solovyev.android.calculator.math.edit.CalculatorFunctionsTabActivity"
 				  a:label="@string/c_functions"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".math.edit.CalculatorOperatorsActivity"
+		<activity a:name="org.solovyev.android.calculator.math.edit.CalculatorOperatorsActivity"
 				  a:label="@string/c_operators"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-        <activity a:name=".math.edit.CalculatorVarsActivity"
+        <activity a:name="org.solovyev.android.calculator.math.edit.CalculatorVarsActivity"
                   a:label="@string/c_vars_and_constants"
                   a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".math.edit.CalculatorVarsTabActivity"
+		<activity a:name="org.solovyev.android.calculator.math.edit.CalculatorVarsTabActivity"
 				  a:label="@string/c_vars_and_constants"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".CalculatorPlotActivity"
+		<activity a:name="org.solovyev.android.calculator.CalculatorPlotActivity"
 				  a:label="@string/c_plot_graph"/>
 
 	</application>

default.properties

@@ -1,11 +0,0 @@
-# This file is automatically generated by Android Tools.
-# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
-#
-# This file must be checked in Version Control Systems.
-#
-# To customize properties used by the Ant build system use,
-# "build.properties", and override values to adapt the script to your
-# project structure.
-
-# Project target.
-target=android-4

pom.xml

@@ -9,7 +9,7 @@
 	<artifactId>calculator</artifactId>
 	<version>1.1.4</version>
 
-	<packaging>pom</packaging>
+	<packaging>jar</packaging>
 
 	<properties>
 		<additionalLibs>${basedir}/src/misc/lib</additionalLibs>
@@ -80,7 +80,6 @@
 			<systemPath>${additionalLibs}/achartengine-0.7.0.jar</systemPath>
 		</dependency>
 
-
 		<dependency>
 			<groupId>com.intellij</groupId>
 			<artifactId>annotations</artifactId>
@@ -88,5 +87,4 @@
 		</dependency>
 
 	</dependencies>
-
 </project>

res/values-es/text_strings.xml

@@ -8,6 +8,7 @@
 
 <resources>
 	<string name="c_app_name">Calculadora++</string>
+	<string name="c_app_name_free">Calculadora++ Free</string>
 	<string name="c_app_icon_name">Calc++</string>
 	<string name="c_app_settings">Configuración</string>
 	<string name="c_syntax_error">Error</string>

res/values-it/text_strings.xml

@@ -8,6 +8,7 @@
 
 <resources>
 	<string name="c_app_name">Calculator++</string>
+	<string name="c_app_name_free">Calculator++ Free</string>
 	<string name="c_app_icon_name">Calc++</string>
     <string name="c_app_settings">Impostazioni</string>
     <string name="c_syntax_error">Errore</string>

res/values-ru/text_strings.xml

@@ -8,6 +8,7 @@
 
 <resources>
 	<string name="c_app_name">Калькулятор++</string>
+	<string name="c_app_name_free">Калькулятор++ Free</string>
 	<string name="c_app_icon_name">Кальк++</string>
 	<string name="c_app_settings">Настройки</string>
 	<string name="c_syntax_error">Ошибка</string>
@@ -162,4 +163,7 @@
 	<string name="c_calc_use_back_button_as_prev_summary">Устанавливает поведение по нажатию на кнопку Назад</string>
 	<string name="c_calc_use_back_button_as_prev_title">Использовать кнопку назад как назад по истории</string>
 
+	<string name="c_warning">Внимание</string>
+	<string name="c_remove_prev_app_warning">Вы установили другую версию Калькулятора++.\nДля корректной работы приложения, пожалуйста, удалите предыдущую версию, все пользовательские данные будут автоматически перенесены в новое приложение.</string>
+
 </resources>

res/values/text_strings.xml

@@ -8,6 +8,7 @@
 
 <resources>
 	<string name="c_app_name">Calculator++</string>
+	<string name="c_app_name_free">Calculator++ Free</string>
 	<string name="c_app_icon_name">Calc++</string>
     <string name="c_app_settings">Settings</string>
     <string name="c_syntax_error">Error</string>
@@ -162,4 +163,7 @@
 	<string name="c_calc_use_back_button_as_prev_summary">Defines the behaviour of the Back button</string>
 	<string name="c_calc_use_back_button_as_prev_title">Use Back button as history prev</string>
 
+	<string name="c_warning">Warning</string>
+	<string name="c_remove_prev_app_warning">It seems that you\'ve installed another version of Calculator++.\nFor correct work of the application please remove previous version, all user data will be automatically transferred to the new version.</string>
+
 </resources>

src/main/java/org/solovyev/android/ResourceCache.java

@@ -15,7 +15,6 @@ import android.view.View;
 import android.widget.Button;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.solovyev.android.calculator.CalculatorActivity;
 import org.solovyev.android.view.widgets.DragButton;
 
 import java.lang.reflect.Field;
@@ -219,7 +218,7 @@ public enum ResourceCache {
 						try {
 							result.put(field.getName(), field.getInt(clazz));
 						} catch (IllegalAccessException e) {
-							Log.e(CalculatorActivity.class.getName(), e.getMessage());
+							Log.e(ResourceCache.class.getName(), e.getMessage());
 						}
 					}
 				}

src/main/java/org/solovyev/android/calculator/AbstractCalculatorActivity.java

@@ -0,0 +1,702 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ */
+
+package org.solovyev.android.calculator;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.Vibrator;
+import android.preference.PreferenceManager;
+import android.text.ClipboardManager;
+import android.text.Html;
+import android.text.method.LinkMovementMethod;
+import android.util.Log;
+import android.util.TypedValue;
+import android.view.*;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.TextView;
+import jscl.AngleUnit;
+import jscl.NumeralBase;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.AndroidUtils;
+import org.solovyev.android.ResourceCache;
+import org.solovyev.android.calculator.about.CalculatorReleaseNotesActivity;
+import org.solovyev.android.calculator.history.CalculatorHistory;
+import org.solovyev.android.calculator.history.CalculatorHistoryState;
+import org.solovyev.android.calculator.math.MathType;
+import org.solovyev.android.calculator.model.CalculatorEngine;
+import org.solovyev.android.view.FontSizeAdjuster;
+import org.solovyev.android.view.prefs.IntegerPreference;
+import org.solovyev.android.view.prefs.Preference;
+import org.solovyev.android.view.prefs.StringPreference;
+import org.solovyev.android.view.widgets.*;
+import org.solovyev.common.utils.Announcer;
+import org.solovyev.common.utils.Point2d;
+import org.solovyev.common.utils.StringUtils;
+import org.solovyev.common.utils.history.HistoryAction;
+
+import java.text.DecimalFormatSymbols;
+import java.util.Locale;
+import java.util.Map;
+
+public abstract class AbstractCalculatorActivity extends Activity implements FontSizeAdjuster, SharedPreferences.OnSharedPreferenceChangeListener {
+
+	private static final int HVGA_WIDTH_PIXELS = 320;
+
+	public static class Preferences {
+		@NotNull
+		private static final String APP_TYPE_P_KEY = "application.type";
+		private static final ApplicationData.Type APP_TYPE_DEFAULT = null;
+		public static final Preference<ApplicationData.Type> appType = StringPreference.newInstance(APP_TYPE_P_KEY, APP_TYPE_DEFAULT, ApplicationData.Type.class);
+
+
+		@NotNull
+		private static final String APP_VERSION_P_KEY = "application.version";
+		private static final int APP_VERSION_DEFAULT = -1;
+		public static final Preference<Integer> appVersion = new IntegerPreference(APP_VERSION_P_KEY, APP_VERSION_DEFAULT);
+	}
+
+	@NotNull
+	public static final String SHOW_RELEASE_NOTES_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_show_release_notes";
+	public static final boolean SHOW_RELEASE_NOTES_P_DEFAULT = true;
+
+	@NotNull
+	public static final String USE_BACK_AS_PREV_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_use_back_button_as_prev";
+	public static final boolean USE_BACK_AS_PREV_DEFAULT = false;
+
+	@NotNull
+	private final Announcer<DragPreferencesChangeListener> dpclRegister = new Announcer<DragPreferencesChangeListener>(DragPreferencesChangeListener.class);
+
+	@NotNull
+	private CalculatorModel calculatorModel;
+
+	private volatile boolean initialized;
+
+	@NotNull
+	private String themeName;
+
+	@NotNull
+	private String layoutName;
+
+	@Nullable
+	private Vibrator vibrator;
+
+	private boolean useBackAsPrev = USE_BACK_AS_PREV_DEFAULT;
+
+	@NotNull
+	private final ApplicationData applicationData;
+
+	protected AbstractCalculatorActivity(@NotNull ApplicationData applicationData) {
+		this.applicationData = applicationData;
+	}
+
+	/**
+	 * Called when the activity is first created.
+	 */
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+
+		final boolean customTitleSupported = requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
+
+		final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
+
+		this.setTitle(this.applicationData.getApplicationTitle());
+
+		setDefaultValues(preferences);
+
+		setTheme(preferences);
+		super.onCreate(savedInstanceState);
+		setLayout(preferences);
+
+		if (customTitleSupported) {
+			try {
+				getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.calc_title);
+				final CalculatorAdditionalTitle additionalAdditionalTitleText = (CalculatorAdditionalTitle)findViewById(R.id.additional_title_text);
+				additionalAdditionalTitleText.init(preferences);
+				preferences.registerOnSharedPreferenceChangeListener(additionalAdditionalTitleText);
+			} catch (ClassCastException e) {
+				// super fix for issue with class cast in android.view.Window.setFeatureInt() (see app error reports)
+				Log.d(AbstractCalculatorActivity.class.getName(), e.getMessage(), e);
+			}
+		}
+
+		ResourceCache.instance.initCaptions(ApplicationContext.getInstance(), R.string.class);
+		firstTimeInit(preferences);
+
+		vibrator = (Vibrator) this.getSystemService(VIBRATOR_SERVICE);
+
+		CalculatorHistory.instance.load(this, preferences);
+		calculatorModel = CalculatorModel.instance.init(this, preferences, CalculatorEngine.instance);
+
+		dpclRegister.clear();
+
+		final SimpleOnDragListener.Preferences dragPreferences = SimpleOnDragListener.getPreferences(preferences, this);
+
+		setOnDragListeners(dragPreferences, preferences);
+
+		final OnDragListener historyOnDragListener = new OnDragListenerVibrator(newOnDragListener(new HistoryDragProcessor<CalculatorHistoryState>(this.calculatorModel), dragPreferences), vibrator, preferences);
+		((DragButton) findViewById(R.id.historyButton)).setOnDragListener(historyOnDragListener);
+
+		((DragButton) findViewById(R.id.subtractionButton)).setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new SimpleOnDragListener.DragProcessor() {
+			@Override
+			public boolean processDragEvent(@NotNull DragDirection dragDirection, @NotNull DragButton dragButton, @NotNull Point2d startPoint2d, @NotNull MotionEvent motionEvent) {
+				if (dragDirection == DragDirection.down) {
+					operatorsButtonClickHandler(dragButton);
+					return true;
+				}
+				return false;
+			}
+		}, dragPreferences), vibrator, preferences));
+
+
+		final OnDragListener toPositionOnDragListener = new OnDragListenerVibrator(new SimpleOnDragListener(new CursorDragProcessor(calculatorModel), dragPreferences), vibrator, preferences);
+		((DragButton) findViewById(R.id.rightButton)).setOnDragListener(toPositionOnDragListener);
+		((DragButton) findViewById(R.id.leftButton)).setOnDragListener(toPositionOnDragListener);
+
+		final DragButton equalsButton = (DragButton) findViewById(R.id.equalsButton);
+		if (equalsButton != null) {
+			equalsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new EvalDragProcessor(calculatorModel), dragPreferences), vibrator, preferences));
+		}
+
+		final AngleUnitsButton angleUnitsButton = (AngleUnitsButton) findViewById(R.id.sixDigitButton);
+		if (angleUnitsButton != null) {
+			angleUnitsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new AngleUnitsChanger(), dragPreferences), vibrator, preferences));
+		}
+
+		final NumeralBasesButton numeralBasesButton = (NumeralBasesButton) findViewById(R.id.clearButton);
+		if (numeralBasesButton != null) {
+			numeralBasesButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new NumeralBasesChanger(), dragPreferences), vibrator, preferences));
+		}
+
+		final DragButton varsButton = (DragButton) findViewById(R.id.varsButton);
+		if (varsButton != null) {
+			varsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new VarsDragProcessor(), dragPreferences), vibrator, preferences));
+		}
+
+		final DragButton roundBracketsButton = (DragButton) findViewById(R.id.roundBracketsButton);
+		if ( roundBracketsButton != null ) {
+			roundBracketsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new RoundBracketsDragProcessor(), dragPreferences), vibrator, preferences));
+		}
+
+
+		CalculatorEngine.instance.reset(this, preferences);
+
+		initMultiplicationButton();
+
+		preferences.registerOnSharedPreferenceChangeListener(this);
+	}
+
+	private class AngleUnitsChanger implements SimpleOnDragListener.DragProcessor {
+
+		private final DigitButtonDragProcessor processor = new DigitButtonDragProcessor(calculatorModel);
+
+		@Override
+		public boolean processDragEvent(@NotNull DragDirection dragDirection,
+										@NotNull DragButton dragButton,
+										@NotNull Point2d startPoint2d,
+										@NotNull MotionEvent motionEvent) {
+			boolean result = false;
+
+			if (dragButton instanceof AngleUnitsButton) {
+				if (dragDirection != DragDirection.left ) {
+					final String directionText = ((AngleUnitsButton) dragButton).getText(dragDirection);
+					if ( directionText != null ) {
+						try {
+
+							final AngleUnit angleUnits = AngleUnit.valueOf(directionText);
+
+							final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(AbstractCalculatorActivity.this);
+
+							CalculatorEngine.Preferences.angleUnit.putPreference(preferences, angleUnits);
+
+							result = true;
+						} catch (IllegalArgumentException e) {
+							Log.d(this.getClass().getName(), "Unsupported angle units: " + directionText);
+						}
+					}
+				} else if ( dragDirection == DragDirection.left ) {
+					result = processor.processDragEvent(dragDirection, dragButton, startPoint2d, motionEvent);
+				}
+			}
+
+			return result;
+		}
+	}
+
+	private class NumeralBasesChanger implements SimpleOnDragListener.DragProcessor {
+
+		@Override
+		public boolean processDragEvent(@NotNull DragDirection dragDirection,
+										@NotNull DragButton dragButton,
+										@NotNull Point2d startPoint2d,
+										@NotNull MotionEvent motionEvent) {
+			boolean result = false;
+
+			if ( dragButton instanceof NumeralBasesButton ) {
+				final String directionText = ((NumeralBasesButton) dragButton).getText(dragDirection);
+				if ( directionText != null ) {
+					try {
+
+						final NumeralBase numeralBase = NumeralBase.valueOf(directionText);
+
+						final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(AbstractCalculatorActivity.this);
+						CalculatorEngine.Preferences.numeralBase.putPreference(preferences, numeralBase);
+
+						result = true;
+					} catch (IllegalArgumentException e) {
+						Log.d(this.getClass().getName(), "Unsupported numeral base: " + directionText);
+					}
+				}
+			}
+
+			return result;
+		}
+	}
+
+
+	private class VarsDragProcessor implements SimpleOnDragListener.DragProcessor {
+
+		@Override
+		public boolean processDragEvent(@NotNull DragDirection dragDirection,
+										@NotNull DragButton dragButton,
+										@NotNull Point2d startPoint2d,
+										@NotNull MotionEvent motionEvent) {
+			boolean result = false;
+
+			if (dragDirection == DragDirection.up) {
+				CalculatorActivityLauncher.createVar(AbstractCalculatorActivity.this, AbstractCalculatorActivity.this.calculatorModel);
+				result = true;
+			}
+
+			return result;
+		}
+	}
+
+	private void setDefaultValues(@NotNull SharedPreferences preferences) {
+		if (!preferences.contains(CalculatorEngine.Preferences.groupingSeparator.getKey())) {
+			final Locale locale = Locale.getDefault();
+			if (locale != null) {
+				final DecimalFormatSymbols decimalFormatSymbols = new DecimalFormatSymbols(locale);
+				int index = MathType.grouping_separator.getTokens().indexOf(String.valueOf(decimalFormatSymbols.getGroupingSeparator()));
+				final String groupingSeparator;
+				if (index >= 0) {
+					groupingSeparator = MathType.grouping_separator.getTokens().get(index);
+				} else {
+					groupingSeparator = " ";
+				}
+
+				CalculatorEngine.Preferences.groupingSeparator.putPreference(preferences, groupingSeparator);
+			}
+		}
+
+		if (!preferences.contains(CalculatorEngine.Preferences.angleUnit.getKey())) {
+			CalculatorEngine.Preferences.angleUnit.putDefault(preferences);
+		}
+
+		if (!preferences.contains(CalculatorEngine.Preferences.numeralBase.getKey())) {
+			CalculatorEngine.Preferences.numeralBase.putDefault(preferences);
+		}
+
+	}
+
+	private synchronized void setOnDragListeners(@NotNull SimpleOnDragListener.Preferences dragPreferences, @NotNull SharedPreferences preferences) {
+		final OnDragListener onDragListener = new OnDragListenerVibrator(newOnDragListener(new DigitButtonDragProcessor(calculatorModel), dragPreferences), vibrator, preferences);
+
+		for (Integer dragButtonId : ResourceCache.instance.getDragButtonIds()) {
+			((DragButton) findViewById(dragButtonId)).setOnDragListener(onDragListener);
+		}
+	}
+
+	@NotNull
+	private SimpleOnDragListener newOnDragListener(@NotNull SimpleOnDragListener.DragProcessor dragProcessor,
+												   @NotNull SimpleOnDragListener.Preferences dragPreferences) {
+		final SimpleOnDragListener onDragListener = new SimpleOnDragListener(dragProcessor, dragPreferences);
+		dpclRegister.addListener(onDragListener);
+		return onDragListener;
+	}
+
+	private class OnDragListenerVibrator extends OnDragListenerWrapper {
+
+		private static final float VIBRATION_TIME_SCALE = 0.5f;
+
+		@NotNull
+		private final VibratorContainer vibrator;
+
+		public OnDragListenerVibrator(@NotNull OnDragListener onDragListener,
+									  @Nullable Vibrator vibrator,
+									  @NotNull SharedPreferences preferences) {
+			super(onDragListener);
+			this.vibrator = new VibratorContainer(vibrator, preferences, VIBRATION_TIME_SCALE);
+		}
+
+		@Override
+		public boolean onDrag(@NotNull DragButton dragButton, @NotNull DragEvent event) {
+			boolean result = super.onDrag(dragButton, event);
+
+			if (result) {
+				vibrator.vibrate();
+			}
+
+			return result;
+		}
+	}
+
+
+	private synchronized void setLayout(@NotNull SharedPreferences preferences) {
+		final Map<String, Integer> layouts = ResourceCache.instance.getNameToIdCache(R.layout.class);
+
+		layoutName = preferences.getString(getString(R.string.p_calc_layout_key), getString(R.string.p_calc_layout));
+
+		Integer layoutId = layouts.get(layoutName);
+		if (layoutId == null) {
+			Log.d(this.getClass().getName(), "No saved layout found => applying default layout: " + R.layout.main_calculator);
+			layoutId = R.layout.main_calculator;
+		} else {
+			Log.d(this.getClass().getName(), "Saved layout found: " + layoutId);
+		}
+
+		setContentView(layoutId);
+	}
+
+	private synchronized void setTheme(@NotNull SharedPreferences preferences) {
+		final Map<String, Integer> styles = ResourceCache.instance.getNameToIdCache(R.style.class);
+
+		themeName = preferences.getString(getString(R.string.p_calc_theme_key), getString(R.string.p_calc_theme));
+
+		Integer styleId = styles.get(themeName);
+		if (styleId == null) {
+			Log.d(this.getClass().getName(), "No saved theme found => applying default theme: " + R.style.default_theme);
+			styleId = R.style.default_theme;
+		} else {
+			Log.d(this.getClass().getName(), "Saved theme found: " + styleId);
+		}
+
+		setTheme(styleId);
+	}
+
+	private synchronized void firstTimeInit(@NotNull SharedPreferences preferences) {
+		if (!initialized) {
+
+			final int savedVersion = Preferences.appVersion.getPreference(preferences);
+			final ApplicationData.Type savedAppType = Preferences.appType.getPreference(preferences);
+
+			final int appVersion = AndroidUtils.getAppVersionCode(this, AbstractCalculatorActivity.class.getPackage().getName());
+			final ApplicationData.Type appType = applicationData.getType();
+
+			Preferences.appVersion.putPreference(preferences, appVersion);
+			Preferences.appType.putPreference(preferences, appType);
+
+			if (savedVersion == Preferences.APP_VERSION_DEFAULT) {
+				// new start
+				final AlertDialog.Builder builder = new AlertDialog.Builder(this).setMessage(R.string.c_first_start_text);
+				builder.setPositiveButton(android.R.string.ok, null);
+				builder.setTitle(R.string.c_first_start_text_title);
+				builder.create().show();
+			} else {
+				if (savedVersion < appVersion) {
+					final boolean showReleaseNotes = preferences.getBoolean(SHOW_RELEASE_NOTES_P_KEY, SHOW_RELEASE_NOTES_P_DEFAULT);
+					if (showReleaseNotes) {
+						final String releaseNotes = CalculatorReleaseNotesActivity.getReleaseNotes(this, savedVersion + 1);
+						if (!StringUtils.isEmpty(releaseNotes)) {
+							final AlertDialog.Builder builder = new AlertDialog.Builder(this).setMessage(Html.fromHtml(releaseNotes));
+							builder.setPositiveButton(android.R.string.ok, null);
+							builder.setTitle(R.string.c_release_notes);
+							builder.create().show();
+						}
+					}
+				}
+			}
+
+			if (savedAppType != appType && savedAppType != null) {
+				// new start
+				final AlertDialog.Builder builder = new AlertDialog.Builder(this).setMessage(R.string.c_remove_prev_app_warning);
+				builder.setPositiveButton(android.R.string.ok, null);
+				builder.setTitle(R.string.c_warning);
+				builder.create().show();
+			}
+
+			ResourceCache.instance.init(R.id.class, this);
+			CalculatorEngine.instance.init(this, preferences);
+
+			initialized = true;
+		}
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void elementaryButtonClickHandler(@NotNull View v) {
+		throw new UnsupportedOperationException("Not implemented yet!");
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void numericButtonClickHandler(@NotNull View v) {
+		this.calculatorModel.evaluate();
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void historyButtonClickHandler(@NotNull View v) {
+		CalculatorActivityLauncher.showHistory(this);
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void eraseButtonClickHandler(@NotNull View v) {
+		calculatorModel.doTextOperation(new CalculatorModel.TextOperation() {
+			@Override
+			public void doOperation(@NotNull EditText editor) {
+				if (editor.getSelectionStart() > 0) {
+					editor.getText().delete(editor.getSelectionStart() - 1, editor.getSelectionStart());
+				}
+			}
+		});
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void simplifyButtonClickHandler(@NotNull View v) {
+		throw new UnsupportedOperationException("Not implemented yet!");
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void moveLeftButtonClickHandler(@NotNull View v) {
+		calculatorModel.moveCursorLeft();
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void moveRightButtonClickHandler(@NotNull View v) {
+		calculatorModel.moveCursorRight();
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void pasteButtonClickHandler(@NotNull View v) {
+		calculatorModel.doTextOperation(new CalculatorModel.TextOperation() {
+			@Override
+			public void doOperation(@NotNull EditText editor) {
+				final ClipboardManager clipboard = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);
+				if (clipboard.hasText()) {
+					editor.getText().insert(editor.getSelectionStart(), clipboard.getText());
+				}
+			}
+		});
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void copyButtonClickHandler(@NotNull View v) {
+		calculatorModel.copyResult(this);
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void clearButtonClickHandler(@NotNull View v) {
+		calculatorModel.clear();
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void digitButtonClickHandler(@NotNull View v) {
+		Log.d(String.valueOf(v.getId()), "digitButtonClickHandler() for: " + v.getId() + ". Pressed: " + v.isPressed());
+		calculatorModel.processDigitButtonAction(((DirectionDragButton) v).getText().toString());
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void functionsButtonClickHandler(@NotNull View v) {
+		CalculatorActivityLauncher.showFunctions(this);
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void operatorsButtonClickHandler(@NotNull View v) {
+		CalculatorActivityLauncher.showOperators(this);
+	}
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void varsButtonClickHandler(@NotNull View v) {
+		CalculatorActivityLauncher.showVars(this);
+	}
+
+	private final static String paypalDonateUrl = "https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=se%2esolovyev%40gmail%2ecom&lc=RU&item_name=Android%20Calculator&currency_code=USD&bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted";
+
+	@SuppressWarnings({"UnusedDeclaration"})
+	public void donateButtonClickHandler(@NotNull View v) {
+		final LayoutInflater layoutInflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
+		final View view = layoutInflater.inflate(R.layout.donate, null);
+
+		final TextView donate = (TextView) view.findViewById(R.id.donateText);
+		donate.setMovementMethod(LinkMovementMethod.getInstance());
+
+		final AlertDialog.Builder builder = new AlertDialog.Builder(this)
+				.setCancelable(true)
+				.setNegativeButton(R.string.c_cancel, null)
+				.setPositiveButton(R.string.c_donate, new DialogInterface.OnClickListener() {
+					@Override
+					public void onClick(DialogInterface dialog, int which) {
+						final Intent i = new Intent(Intent.ACTION_VIEW);
+						i.setData(Uri.parse(paypalDonateUrl));
+						startActivity(i);
+					}
+				})
+				.setView(view);
+
+		builder.create().show();
+	}
+
+	@Override
+	public boolean onKeyDown(int keyCode, KeyEvent event) {
+		if (keyCode == KeyEvent.KEYCODE_BACK) {
+			if (useBackAsPrev) {
+				calculatorModel.doHistoryAction(HistoryAction.undo);
+				return true;
+			}
+		}
+		return super.onKeyDown(keyCode, event);
+	}
+
+
+	@Override
+	public boolean onCreateOptionsMenu(Menu menu) {
+		final MenuInflater menuInflater = getMenuInflater();
+		menuInflater.inflate(R.menu.main_menu, menu);
+		return true;
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		boolean result;
+
+		switch (item.getItemId()) {
+			case R.id.main_menu_item_settings:
+				CalculatorActivityLauncher.showSettings(this);
+				result = true;
+				break;
+			case R.id.main_menu_item_history:
+				CalculatorActivityLauncher.showHistory(this);
+				result = true;
+				break;
+			case R.id.main_menu_item_about:
+				CalculatorActivityLauncher.showAbout(this);
+				result = true;
+				break;
+			case R.id.main_menu_item_help:
+				CalculatorActivityLauncher.showHelp(this);
+				result = true;
+				break;
+			case R.id.main_menu_item_exit:
+				this.finish();
+				result = true;
+				break;
+			default:
+				result = super.onOptionsItemSelected(item);
+		}
+
+		return result;
+	}
+
+	/**
+	 * The font sizes in the layout files are specified for a HVGA display.
+	 * Adjust the font sizes accordingly if we are running on a different
+	 * display.
+	 */
+	@Override
+	public void adjustFontSize(@NotNull TextView view) {
+		float fontPixelSize = view.getTextSize();
+		Display display = getWindowManager().getDefaultDisplay();
+		int h = Math.min(display.getWidth(), display.getHeight());
+		float ratio = (float) h / HVGA_WIDTH_PIXELS;
+		view.setTextSize(TypedValue.COMPLEX_UNIT_PX, fontPixelSize * ratio);
+	}
+
+	public void restart() {
+		final Intent intent = getIntent();
+		/*
+		for compatibility with android_1.6_compatibility
+		overridePendingTransition(0, 0);
+		intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);*/
+
+		Log.d(this.getClass().getName(), "Finishing current activity!");
+		finish();
+
+		/*
+		for compatibility with android_1.6_compatibility
+
+		overridePendingTransition(0, 0);*/
+		Log.d(this.getClass().getName(), "Starting new activity!");
+		startActivity(intent);
+	}
+
+	@Override
+	protected void onResume() {
+		super.onResume();
+
+		final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
+
+		final String newLayoutName = preferences.getString(getString(R.string.p_calc_layout_key), getString(R.string.p_calc_layout));
+		final String newThemeName = preferences.getString(getString(R.string.p_calc_theme_key), getString(R.string.p_calc_theme));
+		if (!themeName.equals(newThemeName) || !layoutName.equals(newLayoutName)) {
+			restart();
+		}
+
+		calculatorModel = CalculatorModel.instance.init(this, preferences, CalculatorEngine.instance);
+		calculatorModel.evaluate(calculatorModel.getDisplay().getJsclOperation());
+	}
+
+	@Override
+	protected void onDestroy() {
+		super.onDestroy();
+	}
+
+	@Override
+	public void onSharedPreferenceChanged(SharedPreferences preferences, @Nullable String key) {
+		if (key != null && key.startsWith("org.solovyev.android.calculator.DragButtonCalibrationActivity")) {
+			dpclRegister.announce().onDragPreferencesChange(SimpleOnDragListener.getPreferences(preferences, this));
+		}
+
+		if (CalculatorEngine.Preferences.getPreferenceKeys().contains(key)) {
+			CalculatorEngine.instance.reset(this, preferences);
+			this.calculatorModel.evaluate();
+		}
+
+		if ( USE_BACK_AS_PREV_P_KEY.equals(key) ) {
+			useBackAsPrev = preferences.getBoolean(USE_BACK_AS_PREV_P_KEY, USE_BACK_AS_PREV_DEFAULT);
+		}
+
+		if ( CalculatorEngine.Preferences.multiplicationSign.getKey().equals(key) ) {
+			initMultiplicationButton();
+		}
+	}
+
+	private void initMultiplicationButton() {
+		final View multiplicationButton = findViewById(R.id.multiplicationButton);
+		if ( multiplicationButton instanceof Button) {
+			((Button) multiplicationButton).setText(CalculatorEngine.instance.getMultiplicationSign());
+		}
+	}
+
+	private static class RoundBracketsDragProcessor implements SimpleOnDragListener.DragProcessor {
+		@Override
+		public boolean processDragEvent(@NotNull DragDirection dragDirection, @NotNull DragButton dragButton, @NotNull Point2d startPoint2d, @NotNull MotionEvent motionEvent) {
+			boolean result = false;
+			if ( dragDirection == DragDirection.left ) {
+				CalculatorModel.instance.doTextOperation(new CalculatorModel.TextOperation() {
+					@Override
+					public void doOperation(@NotNull EditText editor) {
+						final int cursorPosition = editor.getSelectionStart();
+						final StringBuilder text = new StringBuilder("(");
+						final String oldText = editor.getText().toString();
+						text.append(oldText.substring(0, cursorPosition));
+						text.append(")");
+						text.append(oldText.substring(cursorPosition));
+						editor.setText(text);
+						editor.setSelection(cursorPosition + 2);
+					}
+				});
+				result = true;
+			} else {
+				result = new DigitButtonDragProcessor(CalculatorModel.instance).processDragEvent(dragDirection, dragButton, startPoint2d, motionEvent);
+			}
+			return result;
+		}
+	}
+}

src/main/java/org/solovyev/android/calculator/ApplicationData.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2009-2012. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: serso
+ * Date: 1/2/12
+ * Time: 9:08 PM
+ */
+public interface ApplicationData {
+
+	public static enum Type {
+		free,
+		pro
+	}
+
+	boolean isFree();
+
+	boolean isShowAd();
+
+	int getApplicationTitle();
+
+	@NotNull
+	Type getType();
+
+}

src/main/java/org/solovyev/android/calculator/ApplicationDataImpl.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2009-2012. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: serso
+ * Date: 1/2/12
+ * Time: 9:32 PM
+ */
+public class ApplicationDataImpl implements ApplicationData {
+
+	private final boolean free;
+
+	private final int applicationTitle;
+
+	@NotNull
+	private final Type type;
+
+	public ApplicationDataImpl(boolean free, int applicationTitle, @NotNull Type type) {
+		this.free = free;
+		this.applicationTitle = applicationTitle;
+		this.type = type;
+	}
+
+	@Override
+	public boolean isFree() {
+		return this.free;
+	}
+
+	@Override
+	public boolean isShowAd() {
+		return this.free;
+	}
+
+	@Override
+	public int getApplicationTitle() {
+		return this.applicationTitle;
+	}
+
+	@Override
+	@NotNull
+	public Type getType() {
+		return type;
+	}
+}

src/main/java/org/solovyev/android/calculator/CalculatorActivity.java

@@ -1,672 +1,26 @@
 /*
- * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * Copyright (c) 2009-2012. Created by serso aka se.solovyev.
  * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
  */
 
 package org.solovyev.android.calculator;
 
-import android.app.Activity;
-import android.app.AlertDialog;
-import android.content.DialogInterface;
-import android.content.Intent;
-import android.content.SharedPreferences;
-import android.net.Uri;
-import android.os.Bundle;
-import android.os.Vibrator;
-import android.preference.PreferenceManager;
-import android.text.ClipboardManager;
-import android.text.Html;
-import android.text.method.LinkMovementMethod;
-import android.util.Log;
-import android.util.TypedValue;
-import android.view.*;
-import android.widget.Button;
-import android.widget.EditText;
-import android.widget.TextView;
-import jscl.AngleUnit;
-import jscl.NumeralBase;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.solovyev.android.AndroidUtils;
-import org.solovyev.android.ResourceCache;
-import org.solovyev.android.calculator.about.CalculatorReleaseNotesActivity;
-import org.solovyev.android.calculator.history.CalculatorHistory;
-import org.solovyev.android.calculator.history.CalculatorHistoryState;
-import org.solovyev.android.calculator.math.MathType;
-import org.solovyev.android.calculator.model.CalculatorEngine;
-import org.solovyev.android.view.FontSizeAdjuster;
-import org.solovyev.android.view.widgets.*;
-import org.solovyev.android.view.widgets.DragEvent;
-import org.solovyev.common.utils.Announcer;
-import org.solovyev.common.utils.Point2d;
-import org.solovyev.common.utils.StringUtils;
-import org.solovyev.common.utils.history.HistoryAction;
 
-import java.text.DecimalFormatSymbols;
+/**
-import java.util.Locale;
+ * User: serso
-import java.util.Map;
+ * Date: 1/2/12
+ * Time: 9:33 PM
+ */
+public class CalculatorActivity extends AbstractCalculatorActivity {
 
-public class CalculatorActivity extends Activity implements FontSizeAdjuster, SharedPreferences.OnSharedPreferenceChangeListener {
+	public CalculatorActivity() {
-
+		super(createApplicationData());
-	private static final int HVGA_WIDTH_PIXELS = 320;
-	
-	@NotNull
-	public static final String APP_VERSION_P_KEY = "application.version";
-
-	@NotNull
-	public static final String SHOW_RELEASE_NOTES_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_show_release_notes";
-	public static final boolean SHOW_RELEASE_NOTES_P_DEFAULT = true;
-
-	@NotNull
-	public static final String USE_BACK_AS_PREV_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_use_back_button_as_prev";
-	public static final boolean USE_BACK_AS_PREV_DEFAULT = false;
-
-	@NotNull
-	private final Announcer<DragPreferencesChangeListener> dpclRegister = new Announcer<DragPreferencesChangeListener>(DragPreferencesChangeListener.class);
-
-	@NotNull
-	private CalculatorModel calculatorModel;
-
-	private volatile boolean initialized;
-
-	@NotNull
-	private String themeName;
-
-	@NotNull
-	private String layoutName;
-
-	@Nullable
-	private Vibrator vibrator;
-
-	private boolean useBackAsPrev = USE_BACK_AS_PREV_DEFAULT;
-
-	/**
-	 * Called when the activity is first created.
-	 */
-	@Override
-	public void onCreate(@Nullable Bundle savedInstanceState) {
-		Log.d(this.getClass().getName(), "org.solovyev.android.calculator.CalculatorActivity.onCreate()");
-
-		final boolean customTitleSupported = requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
-
-		final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
-
-		setDefaultValues(preferences);
-
-		setTheme(preferences);
-		super.onCreate(savedInstanceState);
-		setLayout(preferences);
-
-		if (customTitleSupported) {
-			try {
-				getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.calc_title);
-				final CalculatorAdditionalTitle additionalAdditionalTitleText = (CalculatorAdditionalTitle)findViewById(R.id.additional_title_text);
-				additionalAdditionalTitleText.init(preferences);
-				preferences.registerOnSharedPreferenceChangeListener(additionalAdditionalTitleText);
-			} catch (ClassCastException e) {
-				// super fix for issue with class cast in android.view.Window.setFeatureInt() (see app error reports)
-				Log.d(CalculatorActivity.class.getName(), e.getMessage(), e);
-			}
-		}
-
-		ResourceCache.instance.initCaptions(ApplicationContext.getInstance(), R.string.class);
-		firstTimeInit(preferences);
-
-		vibrator = (Vibrator) this.getSystemService(VIBRATOR_SERVICE);
-
-		CalculatorHistory.instance.load(this, preferences);
-		calculatorModel = CalculatorModel.instance.init(this, preferences, CalculatorEngine.instance);
-
-		dpclRegister.clear();
-
-		final SimpleOnDragListener.Preferences dragPreferences = SimpleOnDragListener.getPreferences(preferences, this);
-
-		setOnDragListeners(dragPreferences, preferences);
-
-		final OnDragListener historyOnDragListener = new OnDragListenerVibrator(newOnDragListener(new HistoryDragProcessor<CalculatorHistoryState>(this.calculatorModel), dragPreferences), vibrator, preferences);
-		((DragButton) findViewById(R.id.historyButton)).setOnDragListener(historyOnDragListener);
-
-		((DragButton) findViewById(R.id.subtractionButton)).setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new SimpleOnDragListener.DragProcessor() {
-			@Override
-			public boolean processDragEvent(@NotNull DragDirection dragDirection, @NotNull DragButton dragButton, @NotNull Point2d startPoint2d, @NotNull MotionEvent motionEvent) {
-				if (dragDirection == DragDirection.down) {
-					operatorsButtonClickHandler(dragButton);
-					return true;
-				}
-				return false;
-			}
-		}, dragPreferences), vibrator, preferences));
-
-
-		final OnDragListener toPositionOnDragListener = new OnDragListenerVibrator(new SimpleOnDragListener(new CursorDragProcessor(calculatorModel), dragPreferences), vibrator, preferences);
-		((DragButton) findViewById(R.id.rightButton)).setOnDragListener(toPositionOnDragListener);
-		((DragButton) findViewById(R.id.leftButton)).setOnDragListener(toPositionOnDragListener);
-
-		final DragButton equalsButton = (DragButton) findViewById(R.id.equalsButton);
-		if (equalsButton != null) {
-			equalsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new EvalDragProcessor(calculatorModel), dragPreferences), vibrator, preferences));
-		}
-
-		final AngleUnitsButton angleUnitsButton = (AngleUnitsButton) findViewById(R.id.sixDigitButton);
-		if (angleUnitsButton != null) {
-			angleUnitsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new AngleUnitsChanger(), dragPreferences), vibrator, preferences));
-		}
-
-		final NumeralBasesButton numeralBasesButton = (NumeralBasesButton) findViewById(R.id.clearButton);
-		if (numeralBasesButton != null) {
-			numeralBasesButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new NumeralBasesChanger(), dragPreferences), vibrator, preferences));
-		}
-
-		final DragButton varsButton = (DragButton) findViewById(R.id.varsButton);
-		if (varsButton != null) {
-			varsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new VarsDragProcessor(), dragPreferences), vibrator, preferences));
-		}
-
-		final DragButton roundBracketsButton = (DragButton) findViewById(R.id.roundBracketsButton);
-		if ( roundBracketsButton != null ) {
-			roundBracketsButton.setOnDragListener(new OnDragListenerVibrator(newOnDragListener(new RoundBracketsDragProcessor(), dragPreferences), vibrator, preferences));
-		}
-
-
-		CalculatorEngine.instance.reset(this, preferences);
-
-		initMultiplicationButton();
-
-		preferences.registerOnSharedPreferenceChangeListener(this);
-	}
-
-	private class AngleUnitsChanger implements SimpleOnDragListener.DragProcessor {
-
-		private final DigitButtonDragProcessor processor = new DigitButtonDragProcessor(calculatorModel);
-
-		@Override
-		public boolean processDragEvent(@NotNull DragDirection dragDirection,
-										@NotNull DragButton dragButton,
-										@NotNull Point2d startPoint2d,
-										@NotNull MotionEvent motionEvent) {
-			boolean result = false;
-
-			if (dragButton instanceof AngleUnitsButton) {
-				if (dragDirection != DragDirection.left ) {
-					final String directionText = ((AngleUnitsButton) dragButton).getText(dragDirection);
-					if ( directionText != null ) {
-						try {
-
-							final AngleUnit angleUnits = AngleUnit.valueOf(directionText);
-
-							final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(CalculatorActivity.this);
-
-							CalculatorEngine.Preferences.angleUnit.putPreference(preferences, angleUnits);
-
-							result = true;
-						} catch (IllegalArgumentException e) {
-							Log.d(this.getClass().getName(), "Unsupported angle units: " + directionText);
-						}
-					}
-				} else if ( dragDirection == DragDirection.left ) {
-					result = processor.processDragEvent(dragDirection, dragButton, startPoint2d, motionEvent);
-				}
-			}
-
-			return result;
-		}
-	}
-
-	private class NumeralBasesChanger implements SimpleOnDragListener.DragProcessor {
-
-		@Override
-		public boolean processDragEvent(@NotNull DragDirection dragDirection,
-										@NotNull DragButton dragButton,
-										@NotNull Point2d startPoint2d,
-										@NotNull MotionEvent motionEvent) {
-			boolean result = false;
-
-			if ( dragButton instanceof NumeralBasesButton ) {
-				final String directionText = ((NumeralBasesButton) dragButton).getText(dragDirection);
-				if ( directionText != null ) {
-					try {
-
-						final NumeralBase numeralBase = NumeralBase.valueOf(directionText);
-
-						final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(CalculatorActivity.this);
-						CalculatorEngine.Preferences.numeralBase.putPreference(preferences, numeralBase);
-
-						result = true;
-					} catch (IllegalArgumentException e) {
-						Log.d(this.getClass().getName(), "Unsupported numeral base: " + directionText);
-					}
-				}
-			}
-
-			return result;
-		}
-	}
-
-
-	private class VarsDragProcessor implements SimpleOnDragListener.DragProcessor {
-
-		@Override
-		public boolean processDragEvent(@NotNull DragDirection dragDirection,
-										@NotNull DragButton dragButton,
-										@NotNull Point2d startPoint2d,
-										@NotNull MotionEvent motionEvent) {
-			boolean result = false;
-
-			if (dragDirection == DragDirection.up) {
-				CalculatorActivityLauncher.createVar(CalculatorActivity.this, CalculatorActivity.this.calculatorModel);
-				result = true;
-			}
-
-			return result;
-		}
-	}
-
-	private void setDefaultValues(@NotNull SharedPreferences preferences) {
-		if (!preferences.contains(CalculatorEngine.Preferences.groupingSeparator.getKey())) {
-			final Locale locale = Locale.getDefault();
-			if (locale != null) {
-				final DecimalFormatSymbols decimalFormatSymbols = new DecimalFormatSymbols(locale);
-				int index = MathType.grouping_separator.getTokens().indexOf(String.valueOf(decimalFormatSymbols.getGroupingSeparator()));
-				final String groupingSeparator;
-				if (index >= 0) {
-					groupingSeparator = MathType.grouping_separator.getTokens().get(index);
-				} else {
-					groupingSeparator = " ";
-				}
-
-				CalculatorEngine.Preferences.groupingSeparator.putPreference(preferences, groupingSeparator);
-			}
-		}
-
-		if (!preferences.contains(CalculatorEngine.Preferences.angleUnit.getKey())) {
-			CalculatorEngine.Preferences.angleUnit.putDefault(preferences);
-		}
-
-		if (!preferences.contains(CalculatorEngine.Preferences.numeralBase.getKey())) {
-			CalculatorEngine.Preferences.numeralBase.putDefault(preferences);
-		}
-
-	}
-
-	private synchronized void setOnDragListeners(@NotNull SimpleOnDragListener.Preferences dragPreferences, @NotNull SharedPreferences preferences) {
-		final OnDragListener onDragListener = new OnDragListenerVibrator(newOnDragListener(new DigitButtonDragProcessor(calculatorModel), dragPreferences), vibrator, preferences);
-
-		for (Integer dragButtonId : ResourceCache.instance.getDragButtonIds()) {
-			((DragButton) findViewById(dragButtonId)).setOnDragListener(onDragListener);
-		}
 	}
 
 	@NotNull
-	private SimpleOnDragListener newOnDragListener(@NotNull SimpleOnDragListener.DragProcessor dragProcessor,
+	private static ApplicationData createApplicationData() {
-												   @NotNull SimpleOnDragListener.Preferences dragPreferences) {
+		return new ApplicationDataImpl(false, R.string.c_app_name, ApplicationData.Type.pro);
-		final SimpleOnDragListener onDragListener = new SimpleOnDragListener(dragProcessor, dragPreferences);
-		dpclRegister.addListener(onDragListener);
-		return onDragListener;
-	}
-
-	private class OnDragListenerVibrator extends OnDragListenerWrapper {
-
-		private static final float VIBRATION_TIME_SCALE = 0.5f;
-
-		@NotNull
-		private final VibratorContainer vibrator;
-
-		public OnDragListenerVibrator(@NotNull OnDragListener onDragListener,
-									  @Nullable Vibrator vibrator,
-									  @NotNull SharedPreferences preferences) {
-			super(onDragListener);
-			this.vibrator = new VibratorContainer(vibrator, preferences, VIBRATION_TIME_SCALE);
-		}
-
-		@Override
-		public boolean onDrag(@NotNull DragButton dragButton, @NotNull DragEvent event) {
-			boolean result = super.onDrag(dragButton, event);
-
-			if (result) {
-				vibrator.vibrate();
-			}
-
-			return result;
-		}
-	}
-
-
-	private synchronized void setLayout(@NotNull SharedPreferences preferences) {
-		final Map<String, Integer> layouts = ResourceCache.instance.getNameToIdCache(R.layout.class);
-
-		layoutName = preferences.getString(getString(R.string.p_calc_layout_key), getString(R.string.p_calc_layout));
-
-		Integer layoutId = layouts.get(layoutName);
-		if (layoutId == null) {
-			Log.d(this.getClass().getName(), "No saved layout found => applying default layout: " + R.layout.main_calculator);
-			layoutId = R.layout.main_calculator;
-		} else {
-			Log.d(this.getClass().getName(), "Saved layout found: " + layoutId);
-		}
-
-		setContentView(layoutId);
-	}
-
-	private synchronized void setTheme(@NotNull SharedPreferences preferences) {
-		final Map<String, Integer> styles = ResourceCache.instance.getNameToIdCache(R.style.class);
-
-		themeName = preferences.getString(getString(R.string.p_calc_theme_key), getString(R.string.p_calc_theme));
-
-		Integer styleId = styles.get(themeName);
-		if (styleId == null) {
-			Log.d(this.getClass().getName(), "No saved theme found => applying default theme: " + R.style.default_theme);
-			styleId = R.style.default_theme;
-		} else {
-			Log.d(this.getClass().getName(), "Saved theme found: " + styleId);
-		}
-
-		setTheme(styleId);
-	}
-
-	private synchronized void firstTimeInit(@NotNull SharedPreferences preferences) {
-		if (!initialized) {
-			
-			final int savedVersion = preferences.getInt(APP_VERSION_P_KEY, -1);
-			final int appVersion = AndroidUtils.getAppVersionCode(this, CalculatorActivity.class.getPackage().getName());
-			
-			final SharedPreferences.Editor pEditor = preferences.edit();
-			pEditor.putInt(APP_VERSION_P_KEY, appVersion);
-			pEditor.commit();
-
-			if (savedVersion == -1) {
-				// new start
-				final AlertDialog.Builder builder = new AlertDialog.Builder(this).setMessage(R.string.c_first_start_text);
-				builder.setPositiveButton(android.R.string.ok, null);
-				builder.setTitle(R.string.c_first_start_text_title);
-				builder.create().show();
-			} else {
-				if (savedVersion < appVersion) {
-					final boolean showReleaseNotes = preferences.getBoolean(SHOW_RELEASE_NOTES_P_KEY, SHOW_RELEASE_NOTES_P_DEFAULT);
-					if (showReleaseNotes) {
-						final String releaseNotes = CalculatorReleaseNotesActivity.getReleaseNotes(this, savedVersion + 1);
-						if (!StringUtils.isEmpty(releaseNotes)) {
-							final AlertDialog.Builder builder = new AlertDialog.Builder(this).setMessage(Html.fromHtml(releaseNotes));
-							builder.setPositiveButton(android.R.string.ok, null);
-							builder.setTitle(R.string.c_release_notes);
-							builder.create().show();
-						}
-					}
-				}
-			}
-
-			ResourceCache.instance.init(R.id.class, this);
-			CalculatorEngine.instance.init(this, preferences);
-
-			initialized = true;
-		}
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void elementaryButtonClickHandler(@NotNull View v) {
-		throw new UnsupportedOperationException("Not implemented yet!");
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void numericButtonClickHandler(@NotNull View v) {
-		this.calculatorModel.evaluate();
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void historyButtonClickHandler(@NotNull View v) {
-		CalculatorActivityLauncher.showHistory(this);
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void eraseButtonClickHandler(@NotNull View v) {
-		calculatorModel.doTextOperation(new CalculatorModel.TextOperation() {
-			@Override
-			public void doOperation(@NotNull EditText editor) {
-				if (editor.getSelectionStart() > 0) {
-					editor.getText().delete(editor.getSelectionStart() - 1, editor.getSelectionStart());
-				}
-			}
-		});
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void simplifyButtonClickHandler(@NotNull View v) {
-		throw new UnsupportedOperationException("Not implemented yet!");
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void moveLeftButtonClickHandler(@NotNull View v) {
-		calculatorModel.moveCursorLeft();
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void moveRightButtonClickHandler(@NotNull View v) {
-		calculatorModel.moveCursorRight();
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void pasteButtonClickHandler(@NotNull View v) {
-		calculatorModel.doTextOperation(new CalculatorModel.TextOperation() {
-			@Override
-			public void doOperation(@NotNull EditText editor) {
-				final ClipboardManager clipboard = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);
-				if (clipboard.hasText()) {
-					editor.getText().insert(editor.getSelectionStart(), clipboard.getText());
-				}
-			}
-		});
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void copyButtonClickHandler(@NotNull View v) {
-		calculatorModel.copyResult(this);
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void clearButtonClickHandler(@NotNull View v) {
-		calculatorModel.clear();
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void digitButtonClickHandler(@NotNull View v) {
-		Log.d(String.valueOf(v.getId()), "digitButtonClickHandler() for: " + v.getId() + ". Pressed: " + v.isPressed());
-		calculatorModel.processDigitButtonAction(((DirectionDragButton) v).getText().toString());
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void functionsButtonClickHandler(@NotNull View v) {
-		CalculatorActivityLauncher.showFunctions(this);
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void operatorsButtonClickHandler(@NotNull View v) {
-		CalculatorActivityLauncher.showOperators(this);
-	}
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void varsButtonClickHandler(@NotNull View v) {
-		CalculatorActivityLauncher.showVars(this);
-	}
-
-	private final static String paypalDonateUrl = "https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=se%2esolovyev%40gmail%2ecom&lc=RU&item_name=Android%20Calculator&currency_code=USD&bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted";
-
-	@SuppressWarnings({"UnusedDeclaration"})
-	public void donateButtonClickHandler(@NotNull View v) {
-		final LayoutInflater layoutInflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
-		final View view = layoutInflater.inflate(R.layout.donate, null);
-
-		final TextView donate = (TextView) view.findViewById(R.id.donateText);
-		donate.setMovementMethod(LinkMovementMethod.getInstance());
-
-		final AlertDialog.Builder builder = new AlertDialog.Builder(this)
-				.setCancelable(true)
-				.setNegativeButton(R.string.c_cancel, null)
-				.setPositiveButton(R.string.c_donate, new DialogInterface.OnClickListener() {
-					@Override
-					public void onClick(DialogInterface dialog, int which) {
-						final Intent i = new Intent(Intent.ACTION_VIEW);
-						i.setData(Uri.parse(paypalDonateUrl));
-						startActivity(i);
-					}
-				})
-				.setView(view);
-
-		builder.create().show();
-	}
-
-	@Override
-	public boolean onKeyDown(int keyCode, KeyEvent event) {
-		if (keyCode == KeyEvent.KEYCODE_BACK) {
-			if (useBackAsPrev) {
-				calculatorModel.doHistoryAction(HistoryAction.undo);
-				return true;
-			}
-		}
-		return super.onKeyDown(keyCode, event);
-	}
-
-
-	@Override
-	public boolean onCreateOptionsMenu(Menu menu) {
-		final MenuInflater menuInflater = getMenuInflater();
-		menuInflater.inflate(R.menu.main_menu, menu);
-		return true;
-	}
-
-	@Override
-	public boolean onOptionsItemSelected(MenuItem item) {
-		boolean result;
-
-		switch (item.getItemId()) {
-			case R.id.main_menu_item_settings:
-				CalculatorActivityLauncher.showSettings(this);
-				result = true;
-				break;
-			case R.id.main_menu_item_history:
-				CalculatorActivityLauncher.showHistory(this);
-				result = true;
-				break;
-			case R.id.main_menu_item_about:
-				CalculatorActivityLauncher.showAbout(this);
-				result = true;
-				break;
-			case R.id.main_menu_item_help:
-				CalculatorActivityLauncher.showHelp(this);
-				result = true;
-				break;
-			case R.id.main_menu_item_exit:
-				this.finish();
-				result = true;
-				break;
-			default:
-				result = super.onOptionsItemSelected(item);
-		}
-
-		return result;
-	}
-
-	/**
-	 * The font sizes in the layout files are specified for a HVGA display.
-	 * Adjust the font sizes accordingly if we are running on a different
-	 * display.
-	 */
-	@Override
-	public void adjustFontSize(@NotNull TextView view) {
-		float fontPixelSize = view.getTextSize();
-		Display display = getWindowManager().getDefaultDisplay();
-		int h = Math.min(display.getWidth(), display.getHeight());
-		float ratio = (float) h / HVGA_WIDTH_PIXELS;
-		view.setTextSize(TypedValue.COMPLEX_UNIT_PX, fontPixelSize * ratio);
-	}
-
-	public void restart() {
-		final Intent intent = getIntent();
-		/*
-		for compatibility with android_1.6_compatibility
-		overridePendingTransition(0, 0);
-		intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);*/
-
-		Log.d(this.getClass().getName(), "Finishing current activity!");
-		finish();
-
-		/*
-		for compatibility with android_1.6_compatibility
-
-		overridePendingTransition(0, 0);*/
-		Log.d(this.getClass().getName(), "Starting new activity!");
-		startActivity(intent);
-	}
-
-	@Override
-	protected void onResume() {
-		super.onResume();
-
-		final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
-
-		final String newLayoutName = preferences.getString(getString(R.string.p_calc_layout_key), getString(R.string.p_calc_layout));
-		final String newThemeName = preferences.getString(getString(R.string.p_calc_theme_key), getString(R.string.p_calc_theme));
-		if (!themeName.equals(newThemeName) || !layoutName.equals(newLayoutName)) {
-			restart();
-		}
-
-		calculatorModel = CalculatorModel.instance.init(this, preferences, CalculatorEngine.instance);
-		calculatorModel.evaluate(calculatorModel.getDisplay().getJsclOperation());
-	}
-
-	@Override
-	protected void onDestroy() {
-		super.onDestroy();
-	}
-
-	@Override
-	public void onSharedPreferenceChanged(SharedPreferences preferences, @Nullable String key) {
-		if (key != null && key.startsWith("org.solovyev.android.calculator.DragButtonCalibrationActivity")) {
-			dpclRegister.announce().onDragPreferencesChange(SimpleOnDragListener.getPreferences(preferences, this));
-		}
-
-		if (CalculatorEngine.Preferences.getPreferenceKeys().contains(key)) {
-			CalculatorEngine.instance.reset(this, preferences);
-			this.calculatorModel.evaluate();
-		}
-
-		if ( USE_BACK_AS_PREV_P_KEY.equals(key) ) {
-			useBackAsPrev = preferences.getBoolean(USE_BACK_AS_PREV_P_KEY, USE_BACK_AS_PREV_DEFAULT);
-		}
-
-		if ( CalculatorEngine.Preferences.multiplicationSign.getKey().equals(key) ) {
-			initMultiplicationButton();
-		}
-	}
-
-	private void initMultiplicationButton() {
-		final View multiplicationButton = findViewById(R.id.multiplicationButton);
-		if ( multiplicationButton instanceof Button) {
-			((Button) multiplicationButton).setText(CalculatorEngine.instance.getMultiplicationSign());
-		}
-	}
-
-	private static class RoundBracketsDragProcessor implements SimpleOnDragListener.DragProcessor {
-		@Override
-		public boolean processDragEvent(@NotNull DragDirection dragDirection, @NotNull DragButton dragButton, @NotNull Point2d startPoint2d, @NotNull MotionEvent motionEvent) {
-			boolean result = false;
-			if ( dragDirection == DragDirection.left ) {
-				CalculatorModel.instance.doTextOperation(new CalculatorModel.TextOperation() {
-					@Override
-					public void doOperation(@NotNull EditText editor) {
-						final int cursorPosition = editor.getSelectionStart();
-						final StringBuilder text = new StringBuilder("(");
-						final String oldText = editor.getText().toString();
-						text.append(oldText.substring(0, cursorPosition));
-						text.append(")");
-						text.append(oldText.substring(cursorPosition));
-						editor.setText(text);
-						editor.setSelection(cursorPosition + 2);
-					}
-				});
-				result = true;
-			} else {
-				result = new DigitButtonDragProcessor(CalculatorModel.instance).processDragEvent(dragDirection, dragButton, startPoint2d, motionEvent);
-			}
-			return result;
-		}
 	}
 }

src/main/java/org/solovyev/android/calculator/CalculatorActivityFree.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2009-2012. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: serso
+ * Date: 1/2/12
+ * Time: 9:32 PM
+ */
+public class CalculatorActivityFree extends AbstractCalculatorActivity {
+
+	public CalculatorActivityFree() {
+		super(createApplicationData());
+	}
+
+	@NotNull
+	private static ApplicationData createApplicationData() {
+		return new ApplicationDataImpl(true, R.string.c_app_name_free, ApplicationData.Type.free);
+	}
+}

src/main/java/org/solovyev/android/calculator/CalculatorModel.java

@@ -280,7 +280,6 @@ public enum CalculatorModel implements CursorControl, HistoryControl<CalculatorH
 	}
 
 	public void processDigitButtonAction(@Nullable final String text, boolean delayEvaluate) {
-		//Toast.makeText(CalculatorActivity.this, text, Toast.LENGTH_SHORT).show();
 
 		if (!StringUtils.isEmpty(text)) {
 			doTextOperation(new CalculatorModel.TextOperation() {

src/main/java/org/solovyev/android/calculator/about/CalculatorReleaseNotesActivity.java

@@ -15,9 +15,8 @@ import android.widget.TextView;
 import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.AndroidUtils;
 import org.solovyev.android.ResourceCache;
-import org.solovyev.android.calculator.CalculatorActivity;
+import org.solovyev.android.calculator.AbstractCalculatorActivity;
 import org.solovyev.android.calculator.R;
-import org.solovyev.android.AndroidUtils;
 import org.solovyev.common.utils.StringUtils;
 
 /**
@@ -51,7 +50,7 @@ public class CalculatorReleaseNotesActivity extends Activity {
 		final StringBuilder result = new StringBuilder();
 
 		final String releaseNotesForTitle = context.getString(R.string.c_release_notes_for_title);
-		final int version = AndroidUtils.getAppVersionCode(context, CalculatorActivity.class.getPackage().getName());
+		final int version = AndroidUtils.getAppVersionCode(context, AbstractCalculatorActivity.class.getPackage().getName());
 
 		boolean first = true;
 		for ( int i = version; i >= minVersion; i-- ) {

src/main/java/org/solovyev/android/calculator/help/CalculatorHelpTabActivity.java

@@ -15,7 +15,6 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.AndroidUtils;
 import org.solovyev.android.calculator.R;
-import org.solovyev.android.AndroidUtils;
 
 /**
  * User: serso

src/main/java/org/solovyev/android/calculator/history/AbstractHistoryActivity.java

@@ -6,26 +6,29 @@
 
 package org.solovyev.android.calculator.history;
 
-import android.app.AlertDialog;
 import android.app.ListActivity;
 import android.content.Context;
-import android.content.DialogInterface;
 import android.os.Bundle;
-import android.view.*;
+import android.view.MenuInflater;
-import android.widget.*;
+import android.view.MenuItem;
+import android.view.View;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.EditText;
+import android.widget.ListView;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.CalculatorModel;
 import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.jscl.JsclOperation;
-import org.solovyev.android.view.AMenu;
 import org.solovyev.android.view.AMenuBuilder;
-import org.solovyev.android.view.AMenuItem;
 import org.solovyev.android.view.MenuImpl;
 import org.solovyev.common.utils.*;
-import org.solovyev.common.utils.Filter;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
 
 /**
  * User: serso

src/main/java/org/solovyev/android/calculator/history/CalculatorHistoryActivity.java

@@ -12,7 +12,6 @@ import android.widget.TabHost;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.AndroidUtils;
 import org.solovyev.android.calculator.R;
-import org.solovyev.android.AndroidUtils;
 
 /**
  * User: serso

src/main/java/org/solovyev/android/calculator/math/edit/CalculatorVarsActivity.java

@@ -13,7 +13,6 @@ import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.AndroidUtils;
 import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.model.VarCategory;
-import org.solovyev.android.AndroidUtils;
 
 /**
  * User: serso

src/main/java/org/solovyev/android/view/prefs/StringPreference.java

@@ -37,6 +37,11 @@ public class StringPreference<T> extends AbstractPreference<T> {
 		return new StringPreference<T>(id, parser.parseValue(defaultValue), parser);
 	}
 
+	@NotNull
+	public static <T extends Enum> StringPreference<T> newInstance(@NotNull String id, @Nullable T defaultValue, @NotNull Class<T> enumType) {
+		return new StringPreference<T>(id, defaultValue, new EnumMapper<T>(enumType));
+	}
+
 	@Override
 	protected T getPersistedValue(@NotNull SharedPreferences preferences) {
 		return mapper.parseValue(preferences.getString(getKey(), null));