我在我的应用程序中使用范围搜索栏。它工作正常，但我的要求是设置两个拇指之间的范围。默认情况下，两个拇指相互重叠，在我的情况下，拇指不相互重叠。
如何设置范围搜索栏中两个拇指之间的范围？
下面是我的范围搜索栏类。在我的例子中，两个拇指之间的差异是3。如果两个拇指之间的差异是3，则拇指不能重叠。如何设置拇指之间的范围？
这是我使用的课程
public class RangeSeekBar<T extends Number> extends ImageView {
private final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
private final Bitmap thumbImage = BitmapFactory.decodeResource(getResources(), R.drawable.seekcircle_blue);
private final Bitmap thumbPressedImage = BitmapFactory.decodeResource(getResources(), R.drawable.seekcircle_red);
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 = 0.8f * thumbHalfHeight;
private final float padding = thumbHalfWidth;
private final T absoluteMinValue, absoluteMaxValue;
private final NumberType numberType;
private final double absoluteMinValuePrim, absoluteMaxValuePrim;
private double normalizedMinValue = 0d;
private double normalizedMaxValue = 1d;
private Thumb pressedThumb = null;
private boolean notifyWhileDragging = false;
private OnRangeSeekBarChangeListener<T> listener;
/**
* Default color of a {@link RangeSeekBar}, #FF33B5E5. This is also known as "Ice Cream Sandwich" blue.
*/
public static final int DEFAULT_COLOR = Color.argb(0xFF, 0, 0, 0);
/**
* An invalid pointer id.
*/
public static final int INVALID_POINTER_ID = 255;
// Localized constants from MotionEvent for compatibility
// with API < 8 "Froyo".
public static final int ACTION_POINTER_UP = 0x6, ACTION_POINTER_INDEX_MASK = 0x0000ff00, ACTION_POINTER_INDEX_SHIFT = 8;
private float mDownMotionX;
private int mActivePointerId = INVALID_POINTER_ID;
/**
* On touch, this offset plus the scaled value from the position of the touch will form the progress value. Usually 0.
*/
float mTouchProgressOffset;
private int mScaledTouchSlop;
private boolean mIsDragging;
/**
* Creates a new RangeSeekBar.
*
* @param absoluteMinValue
* The minimum value of the selectable range.
* @param absoluteMaxValue
* The maximum value of the selectable range.
* @param context
* @throws IllegalArgumentException
* Will be thrown if min/max value type is not one of Long, Double, Integer, Float, Short, Byte or BigDecimal.
*/
public RangeSeekBar(T absoluteMinValue, T absoluteMaxValue, Context context) throws IllegalArgumentException {
super(context);
this.absoluteMinValue = absoluteMinValue;
this.absoluteMaxValue = absoluteMaxValue;
absoluteMinValuePrim = absoluteMinValue.doubleValue();
absoluteMaxValuePrim = absoluteMaxValue.doubleValue();
numberType = NumberType.fromNumber(absoluteMinValue);
// make RangeSeekBar focusable. This solves focus handling issues in case EditText widgets are being used along with the RangeSeekBar within ScollViews.
setFocusable(true);
setFocusableInTouchMode(true);
init();
}
private final void init() {
mScaledTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
}
public boolean isNotifyWhileDragging() {
return notifyWhileDragging;
}
/**
* Should the widget notify the listener callback while the user is still dragging a thumb? Default is false.
*
* @param flag
*/
public void setNotifyWhileDragging(boolean flag) {
this.notifyWhileDragging = flag;
}
/**
* Returns the absolute minimum value of the range that has been set at construction time.
*
* @return The absolute minimum value of the range.
*/
public T getAbsoluteMinValue() {
return absoluteMinValue;
}
/**
* Returns the absolute maximum value of the range that has been set at construction time.
*
* @return The absolute maximum value of the range.
*/
public T getAbsoluteMaxValue() {
return absoluteMaxValue;
}
/**
* Returns the currently selected min value.
*
* @return The currently selected min value.
*/
public T getSelectedMinValue() {
return normalizedToValue(normalizedMinValue);
}
/**
* Sets the currently selected minimum value. The widget will be invalidated and redrawn.
*
* @param value
* The Number value to set the minimum value to. Will be clamped to given absolute minimum/maximum range.
*/
public void setSelectedMinValue(T value) {
// in case absoluteMinValue == absoluteMaxValue, avoid division by zero when normalizing.
if (0 == (absoluteMaxValuePrim - absoluteMinValuePrim)) {
setNormalizedMinValue(0d);
}
else {
setNormalizedMinValue(valueToNormalized(value));
}
}
/**
* Returns the currently selected max value.
*
* @return The currently selected max value.
*/
public T getSelectedMaxValue() {
return normalizedToValue(normalizedMaxValue);
}
/**
* Sets the currently selected maximum value. The widget will be invalidated and redrawn.
*
* @param value
* The Number value to set the maximum value to. Will be clamped to given absolute minimum/maximum range.
*/
public void setSelectedMaxValue(T value) {
// in case absoluteMinValue == absoluteMaxValue, avoid division by zero when normalizing.
if (0 == (absoluteMaxValuePrim - absoluteMinValuePrim)) {
setNormalizedMaxValue(1d);
}
else {
setNormalizedMaxValue(valueToNormalized(value));
}
}
/**
* Registers given listener callback to notify about changed selected values.
*
* @param listener
* The listener to notify about changed selected values.
*/
public void setOnRangeSeekBarChangeListener(OnRangeSeekBarChangeListener<T> listener) {
this.listener = listener;
}
/**
* Handles thumb selection and movement. Notifies listener callback on certain events.
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
if (!isEnabled())
return false;
int pointerIndex;
final int action = event.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
// Remember where the motion event started
mActivePointerId = event.getPointerId(event.getPointerCount() - 1);
pointerIndex = event.findPointerIndex(mActivePointerId);
mDownMotionX = event.getX(pointerIndex);
pressedThumb = evalPressedThumb(mDownMotionX);
// Only handle thumb presses.
if (pressedThumb == null)
return super.onTouchEvent(event);
setPressed(true);
invalidate();
onStartTrackingTouch();
trackTouchEvent(event);
attemptClaimDrag();
break;
case MotionEvent.ACTION_MOVE:
if (pressedThumb != null) {
if (mIsDragging) {
trackTouchEvent(event);
}
else {
// Scroll to follow the motion event
pointerIndex = event.findPointerIndex(mActivePointerId);
final float x = event.getX(pointerIndex);
if (Math.abs(x - mDownMotionX) > mScaledTouchSlop) {
setPressed(true);
invalidate();
onStartTrackingTouch();
trackTouchEvent(event);
attemptClaimDrag();
}
}
if (listener != null) {
listener.onRangeSeekBarValuesChanged(this, getSelectedMinValue(), getSelectedMaxValue());
}
}
break;
case MotionEvent.ACTION_UP:
if (mIsDragging) {
trackTouchEvent(event);
onStopTrackingTouch();
setPressed(false);
}
else {
// Touch up when we never crossed the touch slop threshold
// should be interpreted as a tap-seek to that location.
onStartTrackingTouch();
trackTouchEvent(event);
onStopTrackingTouch();
}
pressedThumb = null;
invalidate();
if (listener != null) {
listener.onRangeSeekBarValuesChanged(this, getSelectedMinValue(), getSelectedMaxValue());
}
break;
case MotionEvent.ACTION_POINTER_DOWN: {
final int index = event.getPointerCount() - 1;
// final int index = ev.getActionIndex();
mDownMotionX = event.getX(index);
mActivePointerId = event.getPointerId(index);
invalidate();
break;
}
case MotionEvent.ACTION_POINTER_UP:
onSecondaryPointerUp(event);
invalidate();
break;
case MotionEvent.ACTION_CANCEL:
if (mIsDragging) {
onStopTrackingTouch();
setPressed(false);
}
invalidate(); // see above explanation
break;
}
return true;
}
private final void onSecondaryPointerUp(MotionEvent ev) {
final int pointerIndex = (ev.getAction() & ACTION_POINTER_INDEX_MASK) >> ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose
// a new active pointer and adjust accordingly.
// TODO: Make this decision more intelligent.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mDownMotionX = ev.getX(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
}
}
private final void trackTouchEvent(MotionEvent event) {
final int pointerIndex = event.findPointerIndex(mActivePointerId);
final float x = event.getX(pointerIndex);
if (Thumb.MIN.equals(pressedThumb)) {
setNormalizedMinValue(screenToNormalized(x));
}
else if (Thumb.MAX.equals(pressedThumb)) {
setNormalizedMaxValue(screenToNormalized(x));
}
}
/**
* Tries to claim the user's drag motion, and requests disallowing any ancestors from stealing events in the drag.
*/
private void attemptClaimDrag() {
if (getParent() != null) {
getParent().requestDisallowInterceptTouchEvent(true);
}
}
/**
* This is called when the user has started touching this widget.
*/
void onStartTrackingTouch() {
mIsDragging = true;
}
/**
* This is called when the user either releases his touch or the touch is canceled.
*/
void onStopTrackingTouch() {
mIsDragging = false;
}
/**
* Ensures correct size of the widget.
*/
@Override
protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = 200;
if (MeasureSpec.UNSPECIFIED != MeasureSpec.getMode(widthMeasureSpec)) {
width = MeasureSpec.getSize(widthMeasureSpec);
}
int height = thumbImage.getHeight();
if (MeasureSpec.UNSPECIFIED != MeasureSpec.getMode(heightMeasureSpec)) {
height = Math.min(height, MeasureSpec.getSize(heightMeasureSpec));
}
setMeasuredDimension(width, height);
}
/**
* Draws the widget on the given canvas.
*/
@Override
protected synchronized 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));
paint.setStyle(Style.FILL);
paint.setColor(Color.GRAY);
paint.setAntiAlias(true);
canvas.drawRect(rect, paint);
// draw seek bar active range line
rect.left = normalizedToScreen(normalizedMinValue);
rect.right = normalizedToScreen(normalizedMaxValue);
// orange color
paint.setColor(DEFAULT_COLOR);
canvas.drawRect(rect, paint);
// draw minimum thumb
drawThumb(normalizedToScreen(normalizedMinValue), Thumb.MIN.equals(pressedThumb), canvas);
// draw maximum thumb
drawThumb_max(normalizedToScreen(normalizedMaxValue), Thumb.MAX.equals(pressedThumb), canvas);
}
/**
* Overridden to save instance state when device orientation changes. This method is called automatically if you assign an id to the RangeSeekBar widget using the {@link #setId(int)} method. Other members of this class than the normalized min and max values don't need to be saved.
*/
@Override
protected Parcelable onSaveInstanceState() {
final Bundle bundle = new Bundle();
bundle.putParcelable("SUPER", super.onSaveInstanceState());
bundle.putDouble("MIN", normalizedMinValue);
bundle.putDouble("MAX", normalizedMaxValue);
return bundle;
}
/**
* Overridden to restore instance state when device orientation changes. This method is called automatically if you assign an id to the RangeSeekBar widget using the {@link #setId(int)} method.
*/
@Override
protected void onRestoreInstanceState(Parcelable parcel) {
final Bundle bundle = (Bundle) parcel;
super.onRestoreInstanceState(bundle.getParcelable("SUPER"));
normalizedMinValue = bundle.getDouble("MIN");
normalizedMaxValue = bundle.getDouble("MAX");
}
/**
* Draws the "normal" resp. "pressed" thumb image on specified x-coordinate.
*
* @param screenCoord
* The x-coordinate in screen space where to draw the image.
* @param pressed
* Is the thumb currently in "pressed" state?
* @param canvas
* The canvas to draw upon.
*/
private void drawThumb(float screenCoord, boolean pressed, Canvas canvas) {
canvas.drawBitmap(pressed ? thumbImage : thumbImage, screenCoord - thumbHalfWidth, (float) ((0.5f * getHeight()) - thumbHalfHeight), paint);
}
private void drawThumb_max(float screenCoord, boolean pressed, Canvas canvas)
{
canvas.drawBitmap(pressed ? thumbPressedImage : thumbPressedImage, screenCoord - thumbHalfWidth, (float) ((0.5f * getHeight()) - thumbHalfHeight), paint);
}
/**
* Decides which (if any) thumb is touched by the given x-coordinate.
*
* @param touchX
* The x-coordinate of a touch event in screen space.
* @return The pressed thumb or null if none has been touched.
*/
private Thumb evalPressedThumb(float touchX) {
Thumb result = null;
boolean minThumbPressed = isInThumbRange(touchX, normalizedMinValue);
boolean maxThumbPressed = isInThumbRange(touchX, normalizedMaxValue);
if (minThumbPressed && maxThumbPressed) {
// if both thumbs are pressed (they lie on top of each other), choose the one with more room to drag. this avoids "stalling" the thumbs in a corner, not being able to drag them apart anymore.
result = (touchX / getWidth() > 0.5f) ? Thumb.MIN : Thumb.MAX;
}
else if (minThumbPressed) {
result = Thumb.MIN;
}
else if (maxThumbPressed) {
result = Thumb.MAX;
}
return result;
}
/**
* Decides if given x-coordinate in screen space needs to be interpreted as "within" the normalized thumb x-coordinate.
*
* @param touchX
* The x-coordinate in screen space to check.
* @param normalizedThumbValue
* The normalized x-coordinate of the thumb to check.
* @return true if x-coordinate is in thumb range, false otherwise.
*/
private boolean isInThumbRange(float touchX, double normalizedThumbValue) {
return Math.abs(touchX - normalizedToScreen(normalizedThumbValue)) <= thumbHalfWidth;
}
/**
* Sets normalized min value to value so that 0 <= value <= normalized max value <= 1. The View will get invalidated when calling this method.
*
* @param value
* The new normalized min value to set.
*/
public void setNormalizedMinValue(double value) {
normalizedMinValue = Math.max(0d, Math.min(1d, Math.min(value, normalizedMaxValue)));
invalidate();
}
/**
* Sets normalized max value to value so that 0 <= normalized min value <= value <= 1. The View will get invalidated when calling this method.
*
* @param value
* The new normalized max value to set.
*/
public void setNormalizedMaxValue(double value) {
normalizedMaxValue = Math.max(0d, Math.min(1d, Math.max(value, normalizedMinValue)));
invalidate();
}
/**
* Converts a normalized value to a Number object in the value space between absolute minimum and maximum.
*
* @param normalized
* @return
*/
@SuppressWarnings("unchecked")
private T normalizedToValue(double normalized) {
return (T) numberType.toNumber(absoluteMinValuePrim + normalized * (absoluteMaxValuePrim - absoluteMinValuePrim));
}
/**
* Converts the given Number value to a normalized double.
*
* @param value
* The Number value to normalize.
* @return The normalized double.
*/
private double valueToNormalized(T value) {
if (0 == absoluteMaxValuePrim - absoluteMinValuePrim) {
// prevent division by zero, simply return 0.
return 0d;
}
return (value.doubleValue() - absoluteMinValuePrim) / (absoluteMaxValuePrim - absoluteMinValuePrim);
}
/**
* Converts a normalized value into screen space.
*
* @param normalizedCoord
* The normalized value to convert.
* @return The converted value in screen space.
*/
private float normalizedToScreen(double normalizedCoord) {
return (float) (padding + normalizedCoord * (getWidth() - 2 * padding));
}
/**
* Converts screen space x-coordinates into normalized values.
*
* @param screenCoord
* The x-coordinate in screen space to convert.
* @return The normalized value.
*/
private double screenToNormalized(float screenCoord) {
int width = getWidth();
if (width <= 2 * padding) {
// prevent division by zero, simply return 0.
return 0d;
}
else {
double result = (screenCoord - padding) / (width - 2 * padding);
return Math.min(1d, Math.max(0d, result));
}
}
/**
* Callback listener interface to notify about changed range values.
*
* @author Stephan Tittel ([email protected])
*
* @param <T>
* The Number type the RangeSeekBar has been declared with.
*/
public interface OnRangeSeekBarChangeListener<T> {
public void onRangeSeekBarValuesChanged(RangeSeekBar<?> bar, T minValue, T maxValue);
}
/**
* Thumb constants (min and max).
*/
private static enum Thumb {
MIN, MAX
};
/**
* Utility enumaration used to convert between Numbers and doubles.
*
* @author Stephan Tittel ([email protected])
*
*/
private static enum NumberType {
LONG, DOUBLE, INTEGER, FLOAT, SHORT, BYTE, BIG_DECIMAL;
public static <E extends Number> NumberType fromNumber(E value) throws IllegalArgumentException {
if (value instanceof Long) {
return LONG;
}
if (value instanceof Double) {
return DOUBLE;
}
if (value instanceof Integer) {
return INTEGER;
}
if (value instanceof Float) {
return FLOAT;
}
if (value instanceof Short) {
return SHORT;
}
if (value instanceof Byte) {
return BYTE;
}
if (value instanceof BigDecimal) {
return BIG_DECIMAL;
}
throw new IllegalArgumentException("Number class '" + value.getClass().getName() + "' is not supported");
}
public Number toNumber(double value) {
switch (this) {
case LONG:
return new Long((long) value);
case DOUBLE:
return value;
case INTEGER:
return new Integer((int) value);
case FLOAT:
return new Float(value);
case SHORT:
return new Short((short) value);
case BYTE:
return new Byte((byte) value);
case BIG_DECIMAL:
return new BigDecimal(value);
}
throw new InstantiationError("can't convert " + this + " to a Number object");
}
}}
编辑：Java类代码
// create RangeSeekBar as Integer range between 20 and 75
final RangeSeekBar<Integer> seekBar = new RangeSeekBar<Integer>(0, 35, this);
seekBar.setSelectedMinValue(5);
seekBar.setSelectedMaxValue(8);
seekBar.setOnRangeSeekBarChangeListener(new RangeSeekBar.OnRangeSeekBarChangeListener<Integer>() {
@Override
public void onRangeSeekBarValuesChanged(RangeSeekBar<?> bar, Integer minValue, Integer maxValue) {
// handle changed range values
Log.i(TAG, "User selected new range values: MIN=" + minValue + ", MAX=" + maxValue);
int diff=maxValue-minValue;
if(diff==4)
{
}
}
});
// add RangeSeekBar to pre-defined layout
ViewGroup layout = (ViewGroup) findViewById(R.id.layout);
layout.addView(seekBar);
当差异为 4 时停止拇指的运动。您可以使用
if(diff==4) {
bar.setEnabled(false);
}
为了更清楚地了解，请访问我们的blog并看到如何在 RangeSeekBar 中拖动时禁用拇指部分。