我使用GestureDetector.SimpleOnGestureListener的onScroll方法来滚动画布上一个大的位图。如果滚动已经结束我要重新绘制的情况下，用户希望进一步滚动......断位图的边缘位图，但我不能看到如何检测何时滚动已经结束（用户已解除了他的手指从屏幕）。

I am using the onScroll method of GestureDetector.SimpleOnGestureListener to scroll a large bitmap on a canvas. When the scroll has ended I want to redraw the bitmap in case the user wants to scroll further ... off the edge of the bitmap, but I can't see how to detect when the scroll has ended (the user has lifted his finger from the screen).

e2.getAction（）似乎总是返回值2，这样是没有帮助。 e2.get pressure似乎在pressure似乎将下降到大约0.13％至返回相当恒定值（约0.2​​5），直到最后onScroll电话。我想我可以检测到这种减少pressure，但这将是远远万无一失。

e2.getAction() always seems to return the value 2 so that is no help. e2.getPressure seems to return fairly constant values (around 0.25) until the final onScroll call when the pressure seems to fall to about 0.13. I suppose I could detect this reduction in pressure, but this will be far from foolproof.

必须有一个更好的办法？谁能帮助，请

There must be a better way: can anyone help, please?

推荐答案

下面是我解决了这个问题。希望这有助于。

Here is how I solved the problem. Hope this helps.

// declare class member variables
private GestureDetector mGestureDetector;
private OnTouchListener mGestureListener;
private boolean mIsScrolling = false;


public void initGestureDetection() {
        // Gesture detection
    mGestureDetector = new GestureDetector(new SimpleOnGestureListener() {
        @Override
        public boolean onDoubleTap(MotionEvent e) {
            handleDoubleTap(e);
            return true;
        }

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e) {
            handleSingleTap(e);
            return true;
        }

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            // i'm only scrolling along the X axis
            mIsScrolling = true;                
            handleScroll(Math.round((e2.getX() - e1.getX())));
            return true;
        }

        @Override
        /**
         * Don't know why but we need to intercept this guy and return true so that the other gestures are handled.
         * https://code.google.com/p/android/issues/detail?id=8233
         */
        public boolean onDown(MotionEvent e) {
            Log.d("GestureDetector --> onDown");
            return true;
        }
    });

    mGestureListener = new View.OnTouchListener() {
        public boolean onTouch(View v, MotionEvent event) {

            if (mGestureDetector.onTouchEvent(event)) {
                return true;
            }

            if(event.getAction() == MotionEvent.ACTION_UP) {
                if(mIsScrolling ) {
                    Log.d("OnTouchListener --> onTouch ACTION_UP");
                    mIsScrolling  = false;
                    handleScrollFinished();
                };
            }

            return false;
        }
    };

    // attach the OnTouchListener to the image view
    mImageView.setOnTouchListener(mGestureListener);
}