some changes

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

@@ -51,7 +51,7 @@ public abstract class RangeSeekBarPreference<T extends Number> extends AbstractD
 		max = c.convert(maxString == null ? "100" : maxString);
 
 
-		this.rangeSeekBar = new NumberRangeSeekBar<T>(min, max, context);
+		this.rangeSeekBar = new NumberRangeSeekBar<T>(min, max, null, context);
 		rangeSeekBar.setOnRangeSeekBarChangeListener(this);
 	}
 
@@ -70,7 +70,7 @@ public abstract class RangeSeekBarPreference<T extends Number> extends AbstractD
 	protected LinearLayout onCreateDialogView() {
 		final LinearLayout result = super.onCreateDialogView();
 
-		this.rangeSeekBar = new NumberRangeSeekBar<T>(min, max, context);
+		this.rangeSeekBar = new NumberRangeSeekBar<T>(min, max, null, context);
 		rangeSeekBar.setOnRangeSeekBarChangeListener(this);
 		initRangeSeekBar();
 

src/main/java/org/solovyev/android/view/widgets/AbstractRangeSeekBar.java

@@ -14,7 +14,9 @@ import android.widget.ImageView;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.R;
+import org.solovyev.common.math.DiscreteNormalizer;
 import org.solovyev.common.math.LinearNormalizer;
+import org.solovyev.common.math.Normalizer;
 import org.solovyev.common.utils.Converter;
 
 /**
@@ -30,20 +32,7 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	private final Paint paint = new Paint();
 
 	@NotNull
-	private final Bitmap thumbImage = BitmapFactory.decodeResource(getResources(), R.drawable.seek_thumb_normal);
+	private final ThumbContainer tc;
-
-	@NotNull
-	private final Bitmap thumbPressedImage = BitmapFactory.decodeResource(getResources(), R.drawable.seek_thumb_pressed);
-
-	private final float thumbWidth = thumbImage.getWidth();
-
-	private final float thumbHalfWidth = 0.5f * thumbWidth;
-
-	private final float thumbHalfHeight = 0.5f * thumbImage.getHeight();
-
-	private final float lineHeight = 0.3f * thumbHalfHeight;
-
-	private final float padding = thumbHalfWidth;
 
 	@NotNull
 	private final Converter<T, Double> toDoubleConverter;
@@ -55,7 +44,7 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	private final T minValue, maxValue;
 
 	@NotNull
-	private final LinearNormalizer normalizer;
+	private final Normalizer normalizer;
 
 	private double normalizedMinValue = 0d;
 
@@ -77,7 +66,7 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	 * @param context
 	 * @throws IllegalArgumentException Will be thrown if min/max value types are not one of Long, Double, Integer, Float, Short, Byte or BigDecimal.
 	 */
-	public AbstractRangeSeekBar(@NotNull T minValue, @NotNull T maxValue, Context context) throws IllegalArgumentException {
+	public AbstractRangeSeekBar(@NotNull T minValue, @NotNull T maxValue, @Nullable Integer steps, Context context) throws IllegalArgumentException {
 		super(context);
 
 		this.minValue = minValue;
@@ -86,7 +75,13 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 		this.toDoubleConverter = getToDoubleConverter();
 		this.toTConverter = getToTConverter();
 
-		normalizer = new LinearNormalizer(toDoubleConverter.convert(minValue), toDoubleConverter.convert(maxValue));
+		if (steps == null) {
+			normalizer = new LinearNormalizer(toDoubleConverter.convert(minValue), toDoubleConverter.convert(maxValue));
+		} else {
+			normalizer = new DiscreteNormalizer(toDoubleConverter.convert(minValue), toDoubleConverter.convert(maxValue), steps);
+		}
+
+		tc = new ThumbContainer();
 	}
 
 	@NotNull
@@ -216,7 +211,8 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 		if (MeasureSpec.UNSPECIFIED != MeasureSpec.getMode(widthMeasureSpec)) {
 			width = MeasureSpec.getSize(widthMeasureSpec);
 		}
-		int height = thumbImage.getHeight();
+
+		int height = tc.thumbImage.getHeight();
 		if (MeasureSpec.UNSPECIFIED != MeasureSpec.getMode(heightMeasureSpec)) {
 			height = Math.min(height, MeasureSpec.getSize(heightMeasureSpec));
 		}
@@ -230,7 +226,7 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	protected void onDraw(Canvas canvas) {
 		super.onDraw(canvas);
 		// draw seek bar background line
-		final RectF rect = new RectF(padding, 0.5f * (getHeight() - lineHeight), getWidth() - padding, 0.5f * (getHeight() + lineHeight));
+		final RectF rect = tc.getRect();
 		paint.setStyle(Style.FILL);
 		paint.setColor(Color.GRAY);
 		canvas.drawRect(rect, paint);
@@ -256,7 +252,7 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	 * @param canvas	  The canvas to draw upon.
 	 */
 	private void drawThumb(float normalizedToScreenValue, boolean pressed, Canvas canvas) {
-		canvas.drawBitmap(pressed ? thumbPressedImage : thumbImage, normalizedToScreenValue - thumbHalfWidth, (float) ((0.5f * getHeight()) - thumbHalfHeight), paint);
+		canvas.drawBitmap(tc.getImage(pressed), normalizedToScreenValue - tc.thumbHalfWidth, (float) ((0.5f * getHeight()) - tc.thumbHalfHeight), paint);
 	}
 
 	/**
@@ -288,7 +284,7 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	 * @return true if x-coordinate is in thumb range, false otherwise.
 	 */
 	private boolean isInThumbRange(float touchX, double normalizedThumbValue) {
-		return Math.abs(touchX - convertToScreenValue(normalizedThumbValue)) <= thumbHalfWidth;
+		return Math.abs(touchX - convertToScreenValue(normalizedThumbValue)) <= tc.thumbHalfWidth;
 	}
 
 	/**
@@ -341,7 +337,7 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	 * @return The converted value in screen space.
 	 */
 	private float convertToScreenValue(double normalizedValue) {
-		return (float) (padding + normalizedValue * (getWidth() - 2 * padding));
+		return (float) (tc.padding + normalizedValue * (getWidth() - 2 * tc.padding));
 	}
 
 	/**
@@ -352,11 +348,11 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 	 */
 	private double convertToNormalizedValue(float screenValue) {
 		int width = getWidth();
-		if (width <= 2 * padding) {
+		if (width <= 2 * tc.padding) {
 			// prevent division by zero, simply return 0.
 			return 0d;
 		} else {
-			double result = (screenValue - padding) / (width - 2 * padding);
+			double result = (screenValue - tc.padding) / (width - 2 * tc.padding);
 			return Math.min(1d, Math.max(0d, result));
 		}
 	}
@@ -380,4 +376,30 @@ public abstract class AbstractRangeSeekBar<T> extends ImageView {
 		MIN, MAX
 	}
 
+	private class ThumbContainer {
+		@NotNull
+		private final Bitmap thumbImage = BitmapFactory.decodeResource(getResources(), R.drawable.seek_thumb_normal);
+
+		@NotNull
+		private final Bitmap thumbPressedImage = BitmapFactory.decodeResource(getResources(), R.drawable.seek_thumb_pressed);
+
+		private final float thumbWidth = thumbImage.getWidth();
+
+		private final float thumbHalfWidth = 0.5f * thumbWidth;
+
+		private final float thumbHalfHeight = 0.5f * thumbImage.getHeight();
+
+		private final float lineHeight = 0.3f * thumbHalfHeight;
+
+		private final float padding = thumbHalfWidth;
+
+		public RectF getRect() {
+			return new RectF(padding, 0.5f * (getHeight() - lineHeight), getWidth() - padding, 0.5f * (getHeight() + lineHeight));
+		}
+
+		public Bitmap getImage(boolean pressed) {
+			return pressed ? thumbPressedImage : thumbImage;
+		}
+	}
+
 }

src/main/java/org/solovyev/android/view/widgets/NumberRangeSeekBar.java

@@ -2,6 +2,7 @@ package org.solovyev.android.view.widgets;
 
 import android.content.Context;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.solovyev.common.utils.Converter;
 import org.solovyev.common.utils.NumberValuer;
 
@@ -20,11 +21,12 @@ public class NumberRangeSeekBar<T extends Number> extends AbstractRangeSeekBar<T
 	 *
 	 * @param minValue The minimum value of the selectable range.
 	 * @param maxValue The maximum value of the selectable range.
+	 * @param steps number of steps of range
 	 * @param context  parent context
 	 * @throws IllegalArgumentException Will be thrown if min/max value types are not one of Long, Double, Integer, Float, Short, Byte or BigDecimal.
 	 */
-	public NumberRangeSeekBar(@NotNull T minValue, @NotNull T maxValue, Context context) throws IllegalArgumentException {
+	public NumberRangeSeekBar(@NotNull T minValue, @NotNull T maxValue, @Nullable Integer steps, Context context) throws IllegalArgumentException {
-		super(minValue, maxValue, context);
+		super(minValue, maxValue, steps, context);
 
 		numberType = NumberType.fromNumber(minValue);
 
@@ -36,8 +38,8 @@ public class NumberRangeSeekBar<T extends Number> extends AbstractRangeSeekBar<T
 		return new Converter<Double, T>() {
 			@NotNull
 			@Override
-			public T convert(@NotNull Double aDouble) {
+			public T convert(@NotNull Double value) {
-				return (T) numberType.toNumber(aDouble);
+				return (T) numberType.toNumber(value);
 			}
 		};
 	}

src/main/java/org/solovyev/common/math/DiscreteNormalizer.java

@@ -0,0 +1,59 @@
+package org.solovyev.common.math;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: serso
+ * Date: 9/20/11
+ * Time: 5:42 PM
+ */
+public class DiscreteNormalizer implements Normalizer {
+
+	@NotNull
+	private final LinearNormalizer linearNormalizer;
+
+	private final double min;
+
+	private final double step;
+
+	public DiscreteNormalizer(double min, double max, int steps) {
+		assert min <= max;
+		assert steps > 1;
+
+		this.linearNormalizer = new LinearNormalizer(min, max);
+
+		this.step = linearNormalizer.normalize((max - min) / (steps - 1));
+		this.min = linearNormalizer.normalize(min);
+	}
+
+	public DiscreteNormalizer(double min, double max, double step) {
+		assert min <= max;
+		assert step > 0;
+
+		this.linearNormalizer = new LinearNormalizer(min, max);
+
+		this.step = linearNormalizer.normalize(step);
+		this.min = linearNormalizer.normalize(min);
+	}
+
+	@Override
+	public double normalize(double value) {
+		double normalizedValue = linearNormalizer.normalize(value);
+
+		double result = min;
+		while (true) {
+			if ( result + step > normalizedValue ) {
+				break;
+			} else {
+				result += step;
+			}
+		}
+
+		return result;
+	}
+
+	@Override
+	public double denormalize(double value) {
+		return linearNormalizer.denormalize(value);
+	}
+}

src/main/java/org/solovyev/common/math/LinearNormalizer.java

@@ -11,7 +11,7 @@ package org.solovyev.common.math;
 * Date: 9/19/11
 * Time: 9:31 PM
 */
-public class LinearNormalizer {
+public class LinearNormalizer implements Normalizer {
 
 	private final double min;
 	private final double max;
@@ -21,6 +21,7 @@ public class LinearNormalizer {
 		this.max = max;
 	}
 
+	@Override
 	public double normalize(double value){
 		if ((max - min) != 0d) {
 			return (value - min) / (max - min);
@@ -29,6 +30,7 @@ public class LinearNormalizer {
 		}
 	}
 
+	@Override
 	public double denormalize(double value){
 		return min + value * (max - min);
 	}

src/main/java/org/solovyev/common/math/Normalizer.java

@@ -0,0 +1,13 @@
+package org.solovyev.common.math;
+
+/**
+ * User: serso
+ * Date: 9/20/11
+ * Time: 5:30 PM
+ */
+public interface Normalizer {
+
+	double normalize(double value);
+
+	double denormalize(double value);
+}

src/test/java/org/solovyev/common/math/DiscreteNormalizerTest.java

@@ -0,0 +1,35 @@
+package org.solovyev.common.math;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.solovyev.common.utils.MathUtils;
+
+/**
+ * User: serso
+ * Date: 9/20/11
+ * Time: 5:51 PM
+ */
+public class DiscreteNormalizerTest {
+
+	@Test
+	public void testNormalize() throws Exception {
+	 	DiscreteNormalizer dn = new DiscreteNormalizer(0, 10, 1);
+
+		Assert.assertTrue(MathUtils.equals(0, dn.normalize(0.5), 2));
+		Assert.assertTrue(MathUtils.equals(0, dn.normalize(0.99), 2));
+		Assert.assertTrue(MathUtils.equals(0.1, dn.normalize(1), 2));
+		Assert.assertTrue(MathUtils.equals(0.1, dn.normalize(1.01), 2));
+		Assert.assertTrue(MathUtils.equals(1, dn.normalize(10), 2));
+		Assert.assertTrue(MathUtils.equals(0.9, dn.normalize(9.99), 2));
+	}
+
+	@Test
+	public void testDenormalize() throws Exception {
+		DiscreteNormalizer dn = new DiscreteNormalizer(0, 10, 1);
+
+		Assert.assertTrue(MathUtils.equals(0, dn.normalize(dn.denormalize(0)), 2));
+		Assert.assertTrue(MathUtils.equals(0.1, dn.normalize(dn.denormalize(0.1)), 2));
+		Assert.assertTrue(MathUtils.equals(1, dn.normalize(dn.denormalize(1)), 2));
+		Assert.assertTrue(MathUtils.equals(0.9, dn.normalize(dn.denormalize(0.9)), 2));
+	}
+}