带有 android 的最高和最低价格的价格栏

Question

我怎样才能用 android (java) 做到这一点？

Answer 1

好的，你可以使用预定义的库来实现，会有两个拇指，你会得到左右拇指值。

使用这个Material Range Bar

Answer 2

您可以在下面使用Range-Seek-Bar

check below class souce code available here

public class RangeSeekBar<T extends Number> extends ImageView {

public static final Integer DEFAULT_MINIMUM = 0;
public static final Integer DEFAULT_MAXIMUM = 100;
public static final int HEIGHT_IN_DP = 30;
public static final int TEXT_LATERAL_PADDING_IN_DP = 3;
private static final int INITIAL_PADDING_IN_DP = 8;
private final int LINE_HEIGHT_IN_DP = 1;
private final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
private final Bitmap thumbImage = BitmapFactory.decodeResource(getResources(), R.drawable.seek_thumb_normal);
private final Bitmap thumbPressedImage = BitmapFactory.decodeResource(getResources(),
                                                                      R.drawable.seek_thumb_pressed);
private final Bitmap thumbDisabledImage = BitmapFactory.decodeResource(getResources(),
                                                                       R.drawable.seek_thumb_disabled);
private final float thumbWidth = thumbImage.getWidth();
private final float thumbHalfWidth = 0.5f * thumbWidth;
private final float thumbHalfHeight = 0.5f * thumbImage.getHeight();
private float INITIAL_PADDING;
private float padding;
private T absoluteMinValue, absoluteMaxValue;
private NumberType numberType;
private 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, 0x33, 0xB5, 0xE5);
/**
 * 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;

private int mScaledTouchSlop;

private boolean mIsDragging;

private int mTextOffset;
private int mTextSize;
private int mDistanceToTop;
private RectF mRect;

private static final int DEFAULT_TEXT_SIZE_IN_DP = 14;
private static final int DEFAULT_TEXT_DISTANCE_TO_BUTTON_IN_DP = 8;
private static final int DEFAULT_TEXT_DISTANCE_TO_TOP_IN_DP = 8;
private boolean mSingleThumb;

public RangeSeekBar(Context context) {
    super(context);
    init(context, null);
}

public RangeSeekBar(Context context, AttributeSet attrs) {
    super(context, attrs);
    init(context, attrs);
}

public RangeSeekBar(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init(context, attrs);
}

private T extractNumericValueFromAttributes(TypedArray a, int attribute, int defaultValue) {
    TypedValue tv = a.peekValue(attribute);
    if (tv == null) {
        return (T) Integer.valueOf(defaultValue);
    }

    int type = tv.type;
    if (type == TypedValue.TYPE_FLOAT) {
        return (T) Float.valueOf(a.getFloat(attribute, defaultValue));
    } else {
        return (T) Integer.valueOf(a.getInteger(attribute, defaultValue));
    }
}

private void init(Context context, AttributeSet attrs) {
    if (attrs == null) {
        setRangeToDefaultValues();
    } else {
        TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.RangeSeekBar, 0, 0);
        setRangeValues(
                extractNumericValueFromAttributes(a, R.styleable.RangeSeekBar_absoluteMinValue, DEFAULT_MINIMUM),
                extractNumericValueFromAttributes(a, R.styleable.RangeSeekBar_absoluteMaxValue, DEFAULT_MAXIMUM));
        mSingleThumb = a.getBoolean(R.styleable.RangeSeekBar_singleThumb, false);
        a.recycle();
    }

    setValuePrimAndNumberType();

    INITIAL_PADDING = PixelUtil.dpToPx(context, INITIAL_PADDING_IN_DP);

    mTextSize = PixelUtil.dpToPx(context, DEFAULT_TEXT_SIZE_IN_DP);
    mDistanceToTop = PixelUtil.dpToPx(context, DEFAULT_TEXT_DISTANCE_TO_TOP_IN_DP);
    mTextOffset = this.mTextSize + PixelUtil.dpToPx(context,
                                                    DEFAULT_TEXT_DISTANCE_TO_BUTTON_IN_DP) + this.mDistanceToTop;

    float lineHeight = PixelUtil.dpToPx(context, LINE_HEIGHT_IN_DP);
    mRect = new RectF(padding,
                      mTextOffset + thumbHalfHeight - lineHeight / 2,
                      getWidth() - padding,
                      mTextOffset + thumbHalfHeight + lineHeight / 2);

    // 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);
    mScaledTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
}

public void setRangeValues(T minValue, T maxValue) {
    this.absoluteMinValue = minValue;
    this.absoluteMaxValue = maxValue;
    setValuePrimAndNumberType();
}

@SuppressWarnings("unchecked")
// only used to set default values when initialised from XML without any values specified
private void setRangeToDefaultValues() {
    this.absoluteMinValue = (T) DEFAULT_MINIMUM;
    this.absoluteMaxValue = (T) DEFAULT_MAXIMUM;
    setValuePrimAndNumberType();
}

private void setValuePrimAndNumberType() {
    absoluteMinValuePrim = absoluteMinValue.doubleValue();
    absoluteMaxValuePrim = absoluteMaxValue.doubleValue();
    numberType = NumberType.fromNumber(absoluteMinValue);
}

public void resetSelectedValues() {
    setSelectedMinValue(absoluteMinValue);
    setSelectedMaxValue(absoluteMaxValue);
}

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 (notifyWhileDragging && 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) && !mSingleThumb) {
        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() + PixelUtil.dpToPx(getContext(), HEIGHT_IN_DP);
    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);

    paint.setTextSize(mTextSize);
    paint.setStyle(Style.FILL);
    paint.setColor(Color.GRAY);
    paint.setAntiAlias(true);

    // draw min and max labels
    String minLabel = getContext().getString(R.string.demo_min_label);
    String maxLabel = getContext().getString(R.string.demo_max_label);
    float minMaxLabelSize = Math.max(paint.measureText(minLabel), paint.measureText(maxLabel));
    float minMaxHeight = mTextOffset + thumbHalfHeight + mTextSize / 3;
    canvas.drawText(minLabel, 0, minMaxHeight, paint);
    canvas.drawText(maxLabel, getWidth() - minMaxLabelSize, minMaxHeight, paint);
    padding = INITIAL_PADDING + minMaxLabelSize + thumbHalfWidth;

    // draw seek bar background line
    mRect.left = padding;
    mRect.right = getWidth() - padding;
    canvas.drawRect(mRect, paint);

    boolean selectedValuesAreDefault = (getSelectedMinValue().equals(getAbsoluteMinValue()) &&
            getSelectedMaxValue().equals(getAbsoluteMaxValue()));

    int colorToUseForButtonsAndHighlightedLine = selectedValuesAreDefault ?
            Color.GRAY :    // default values
            DEFAULT_COLOR; //non default, filter is active

    // draw seek bar active range line
    mRect.left = normalizedToScreen(normalizedMinValue);
    mRect.right = normalizedToScreen(normalizedMaxValue);

    paint.setColor(colorToUseForButtonsAndHighlightedLine);
    canvas.drawRect(mRect, paint);

    // draw minimum thumb if not a single thumb control
    if (!mSingleThumb) {
        drawThumb(normalizedToScreen(normalizedMinValue), Thumb.MIN.equals(pressedThumb), canvas,
                  selectedValuesAreDefault);
    }

    // draw maximum thumb
    drawThumb(normalizedToScreen(normalizedMaxValue), Thumb.MAX.equals(pressedThumb), canvas,
              selectedValuesAreDefault);

    // draw the text if sliders have moved from default edges
    if (!selectedValuesAreDefault) {
        paint.setTextSize(mTextSize);
        paint.setColor(Color.WHITE);
        // give text a bit more space here so it doesn't get cut off
        int offset = PixelUtil.dpToPx(getContext(), TEXT_LATERAL_PADDING_IN_DP);

        String minText = String.valueOf(getSelectedMinValue());
        String maxText = String.valueOf(getSelectedMaxValue());
        float minTextWidth = paint.measureText(minText) + offset;
        float maxTextWidth = paint.measureText(maxText) + offset;

        if (!mSingleThumb) {
            canvas.drawText(minText,
                            normalizedToScreen(normalizedMinValue) - minTextWidth * 0.5f,
                            mDistanceToTop + mTextSize,
                            paint);

        }

        canvas.drawText(maxText,
                        normalizedToScreen(normalizedMaxValue) - maxTextWidth * 0.5f,
                        mDistanceToTop + mTextSize,
                        paint);
    }

}

/**
 * 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, boolean areSelectedValuesDefault) {
    Bitmap buttonToDraw;
    if (areSelectedValuesDefault) {
        buttonToDraw = thumbDisabledImage;
    } else {
        buttonToDraw = pressed ? thumbPressedImage : thumbImage;
    }

    canvas.drawBitmap(buttonToDraw, screenCoord - thumbHalfWidth,
                      mTextOffset,
                      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.
 */
private 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.
 */
private 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) {
    double v = absoluteMinValuePrim + normalized * (absoluteMaxValuePrim - absoluteMinValuePrim);
    // TODO parameterize this rounding to allow variable decimal points
    return (T) numberType.toNumber(Math.round(v * 100) / 100d);
}

/**
 * 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.
 *
 * @param <T> The Number type the RangeSeekBar has been declared with.
 * @author Stephan Tittel (stephan.tittel@kom.tu-darmstadt.de)
 */
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 enumeration used to convert between Numbers and doubles.
 *
 * @author Stephan Tittel (stephan.tittel@kom.tu-darmstadt.de)
 */
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 Long.valueOf((long) value);
            case DOUBLE:
                return value;
            case INTEGER:
                return Integer.valueOf((int) value);
            case FLOAT:
                return Float.valueOf((float)value);
            case SHORT:
                return Short.valueOf((short) value);
            case BYTE:
                return Byte.valueOf((byte) value);
            case BIG_DECIMAL:
                return BigDecimal.valueOf(value);
        }
        throw new InstantiationError("can't convert " + this + " to a Number object");
    }
}

}