实现 GestureDetector 以拖动、DoubleTap 和 singleTap 一个 ImageView

Question

我正在尝试实现一个 ImageView，它会对每个操作（拖动、双击和单击）产生不同的反应。我正在做的基于本教程： DoubleTap in android

我用来创建班级的：

public class MyIcon extends ImageView {

    GestureDetector gestureDetector;

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // creating new gesture detector
        gestureDetector = new GestureDetector(context, new GestureListener());
    }

    // skipping measure calculation and drawing

    // delegate the event to the gesture detector
    @Override
    public boolean onTouchEvent(MotionEvent e) {
        return gestureDetector.onTouchEvent(e);
    }


    private class GestureListener extends GestureDetector.SimpleOnGestureListener {

        @Override
        public boolean onDown(MotionEvent e) {
            return true;
        }
        // event when double tap occurs
        @Override
        public boolean onDoubleTap(MotionEvent e) {
            //A Toast just to see if it is working
            return true;
        }
        @Override
        public boolean onShowPress(MotionEvent e) {
            //A Toast just to see if it is working
            return true;
        }
    }
}

实例化：

private WindowManager windowManager;
private MyIcon myIcon;
private WindowManager.LayoutParams params;

windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);

    chatHead = new MyIcon(this);
    chatHead.setImageResource(R.mipmap.ic_launcher);

    params = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.TYPE_PHONE,
            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
            PixelFormat.TRANSPARENT
    );

    params.gravity = Gravity.TOP | Gravity.LEFT;
    params.x = 0;
    params.y = 100;

我使用了 setOnTouchListener()，它可以很好地进行拖动，但它不适用于 DoubleTap。

实现和实例化这个类以使其同时工作的正确方法是什么？

Answer 1

试试这个SimpleGestureFilter

public class SimpleGestureFilter extends SimpleOnGestureListener {

    public final static int SWIPE_UP = 1;
    public final static int SWIPE_DOWN = 2;
    public final static int SWIPE_LEFT = 3;
    public final static int SWIPE_RIGHT = 4;

    public final static int MODE_TRANSPARENT = 0;
    public final static int MODE_SOLID = 1;
    public final static int MODE_DYNAMIC = 2;

    private final static int ACTION_FAKE = -13; // just an unlikely number
    private int swipe_Min_Distance = 100;
    private int swipe_Max_Distance = 350;
    private int swipe_Min_Velocity = 100;

    private int mode = MODE_DYNAMIC;
    private boolean running = true;
    private boolean tapIndicator = false;

    private Activity context;
    private GestureDetector detector;
    private SimpleGestureListener listener;

    public SimpleGestureFilter(Activity context, SimpleGestureListener sgl) {

        this.context = context;
        this.detector = new GestureDetector(context, this);
        this.listener = sgl;
    }

    public void onTouchEvent(MotionEvent event) {

        if (!this.running)
            return;

        boolean result = this.detector.onTouchEvent(event);

        if (this.mode == MODE_SOLID)
            event.setAction(MotionEvent.ACTION_CANCEL);
        else if (this.mode == MODE_DYNAMIC) {

            if (event.getAction() == ACTION_FAKE)
                event.setAction(MotionEvent.ACTION_UP);
            else if (result)
                event.setAction(MotionEvent.ACTION_CANCEL);
            else if (this.tapIndicator) {
                event.setAction(MotionEvent.ACTION_DOWN);
                this.tapIndicator = false;
            }

        }
        // else just do nothing, it's Transparent
    }

    public void setMode(int m) {
        this.mode = m;
    }

    public int getMode() {
        return this.mode;
    }

    public void setEnabled(boolean status) {
        this.running = status;
    }

    public void setSwipeMaxDistance(int distance) {
        this.swipe_Max_Distance = distance;
    }

    public void setSwipeMinDistance(int distance) {
        this.swipe_Min_Distance = distance;
    }

    public void setSwipeMinVelocity(int distance) {
        this.swipe_Min_Velocity = distance;
    }

    public int getSwipeMaxDistance() {
        return this.swipe_Max_Distance;
    }

    public int getSwipeMinDistance() {
        return this.swipe_Min_Distance;
    }

    public int getSwipeMinVelocity() {
        return this.swipe_Min_Velocity;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {

        final float xDistance = Math.abs(e1.getX() - e2.getX());
        final float yDistance = Math.abs(e1.getY() - e2.getY());

        if (xDistance > this.swipe_Max_Distance
                || yDistance > this.swipe_Max_Distance)
            return false;

        velocityX = Math.abs(velocityX);
        velocityY = Math.abs(velocityY);
        boolean result = false;

        if (velocityX > this.swipe_Min_Velocity
                && xDistance > this.swipe_Min_Distance) {
            if (e1.getX() > e2.getX()) // right to left
                this.listener.onSwipe(SWIPE_LEFT);
            else
                this.listener.onSwipe(SWIPE_RIGHT);

            result = true;
        } else if (velocityY > this.swipe_Min_Velocity
                && yDistance > this.swipe_Min_Distance) {
            if (e1.getY() > e2.getY()) // bottom to up
                this.listener.onSwipe(SWIPE_UP);
            else
                this.listener.onSwipe(SWIPE_DOWN);

            result = true;
        }

        return result;
    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        this.tapIndicator = true;
        return false;
    }

    @Override
    public boolean onDoubleTap(MotionEvent arg) {
        this.listener.onDoubleTap();
        ;
        return true;
    }

    @Override
    public boolean onDoubleTapEvent(MotionEvent arg) {
        return true;
    }

    @Override
    public boolean onSingleTapConfirmed(MotionEvent arg) {

        if (this.mode == MODE_DYNAMIC) { // we owe an ACTION_UP, so we fake an
            arg.setAction(ACTION_FAKE); // action which will be converted to an
                                        // ACTION_UP later.
            this.context.dispatchTouchEvent(arg);
        }

        return false;
    }

    static interface SimpleGestureListener {
        void onSwipe(int direction);

        void onDoubleTap();
    }

}

以这种方式在代码中使用

   private SimpleGestureFilter detector;

   detector = new SimpleGestureFilter(this, this);              

改这个方法就行了

    @Override
    public boolean dispatchTouchEvent(MotionEvent me) {
        // Call onTouchEvent of SimpleGestureFilter class
        this.detector.onTouchEvent(me);
        return super.dispatchTouchEvent(me);
    }