Android多点触摸支持

我想知道Android多点触摸支持是否可靠？我读到它有一些问题

我还想知道，如何定义自定义多点触控手势？例如：3个手指旋转或3个手指静止，第四个手指移动

我遇到过一些资源（developer.android.com上的手势或MotionEvent），但没有明确说明

问候,

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Zdenek

我在API中进行了深入研究，找到了一种执行捏/反向捏等手势的方法，因此我相信您描述的手势是可能的——只需要弄清楚如何编写它们。下面我粘贴了一个我实现的反向挤压示例。我希望只有在水平方向的情况下，夹点才能注册。它不是非常干净或可重用的代码，但它应该可以帮助您向前迈进。它在安卓2.0.x上运行。我读过multi-touch在早期版本中可能存在问题。该示例是我从活动的

onTouchEvent

中调用的一个类，将事件转发给该类

public class HorizontalReversePinchDetector {

    public boolean onTouchEvent(MotionEvent e) {

        int pointerCount = e.getPointerCount();

        if(pointerCount != 2) {
            Log.d(GESTURE, "not pinching - exactly 2 fingers are needed but have " + pointerCount);
            clearPinch();
            return false;
        }

        int firstIndex = e.getX(0) < e.getX(1) ? 0: 1;
        int secondIndex = e.getX(0) < e.getX(1) ? 1: 0;

        Finger currentLeftFinger = new Finger(e.getX(firstIndex), e.getY(firstIndex));
        Finger currentRightFinger = new Finger(e.getX(secondIndex), e.getY(secondIndex));

        float yDifference = Math.abs(currentLeftFinger.getY() - currentRightFinger.getY());
        if(yDifference > 80) {
            Log.d(GESTURE, "not pinching - fingers too vertically-oriented");
            clearPinch();
            return false;
        }

        if(initialLeftFinger == null) {
            initialLeftFinger = currentLeftFinger;
            initialRightFinger = currentRightFinger;
            Log.d(GESTURE, "not pinching, but might be starting a pinch...");
            return false;
        }

        float leftFingerDistance = initialLeftFinger.getX() - currentLeftFinger.getX();
        float rightFingerDistance = currentRightFinger.getX() - initialRightFinger.getX();

        float xDistanceBetweenFingers = Math.abs(currentLeftFinger.getX() - currentRightFinger.getX());
        if(xDistanceBetweenFingers < minimumDistanceBetweenFingers) {
            Log.d(GESTURE, "pinching, but fingers are not far enough apart...");
            return true;
        }

        if(leftFingerDistance < minimumDistanceForEachFinger) {
            Log.d(GESTURE, "pinching, but left finger has not moved enough...");
            return true;
        }
        if(rightFingerDistance < minimumDistanceForEachFinger) {
            Log.d(GESTURE, "pinching, but right finger has not moved enough...");
            return true;
        }

        pinchCompleted();
        return true;
    }

    private void pinchCompleted() {
        Log.d(GESTURE, "pinch completed");
        if(pinchListener != null) pinchListener.onPinch();
        clearPinch();
    }

    public static interface OnPinchListener {
        void onPinch();
    }

    private void clearPinch() {
        initialLeftFinger = null;
        initialRightFinger = null;
    }

    public void setPinchListener(OnPinchListener pinchListener) {
        this.pinchListener = pinchListener;
    }

    private static class Finger {

        private Finger(float x, float y) {
            this.x = x;
            this.y = y;
        }

        public float getX() {
            return x;
        }

        public float getY() {
            return y;
        }

        private float x;
        private float y;
    }

    private Finger initialLeftFinger;
    private Finger initialRightFinger;
    private OnPinchListener pinchListener;
    private static final float minimumDistanceForEachFinger = 30;
    private static final float minimumDistanceBetweenFingers = 50;
}

公共类水平反转检测器{
公共事件（运动事件e）{
int pointerCount=e.getPointerCount（）；
如果（指针计数！=2）{
Log.d（手势，“不捏-只需要两个手指，但有”+指针计数）；
clearPinch（）；
返回false；
}
int firstIndex=e.getX（0）80）{
Log.d（手势，“不要捏——手指太垂直”）；
clearPinch（）；
返回false；
}
if（initialLeftFinger==null）{
initialLeftFinger=当前LeftFinger；
initialRightFinger=当前RightFinger；
Log.d（手势“不是捏，但可能是开始捏…”）；
返回false；
}
float leftFingerDistance=initialLeftFinger.getX（）-currentLeftFinger.getX（）；
float rightFingerDistance=currentRightFinger.getX（）-initialRightFinger.getX（）；
float xDistanceBetweenFingers=Math.abs（currentLeftFinger.getX（）-currentRightFinger.getX（））；
if（XDdistance between finger

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关于可靠性，本规范是完全可靠的。同样，仅在Android 2.0.x上。我没有在平台的其他版本上测试过它。

太好了！谢谢你的回复，这正是我一直在寻找的东西。