Android Fragment onCreateView 与手势

我正在尝试在片段中使用手势；我在 FragmentActivity 中有以下内容来处理我的详细信息片段。我试图发生的情况是，当在视图上检测到滑动时，将该视图内的数据替换为上一个或下一个条目。

如果有更好的方法来处理这个问题；我完全同意。然而，这里发生的情况是 onFling 方法从未被实际调用。

public static class DetailsFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
        if (container == null) {
            return null;
        }
        View v = inflater.inflate(R.layout.my_view, null, false);
        final GestureDetector gesture = new GestureDetector(getActivity(),
            new GestureDetector.SimpleOnGestureListener() {
                @Override
                public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                    float velocityY) {

                    final int SWIPE_MIN_DISTANCE = 120;
                    final int SWIPE_MAX_OFF_PATH = 250;
                    final int SWIPE_THRESHOLD_VELOCITY = 200;
                    try {
                        if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                            return false;
                        if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
                            && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                            Log.i(Constants.APP_TAG, "Right to Left");
                        } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
                            && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                            Log.i(Constants.APP_TAG, "Left to Right");
                            titles.showDetails(getPosition() - 1);
                        }
                    } catch (Exception e) {
                        // nothing
                    }
                    return super.onFling(e1, e2, velocityX, velocityY);
                }
            });

        v.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return gesture.onTouchEvent(event);
            }
        });

        return v;
    }
}

看起来以下问题解释了这一点：Android：GestureDetector 无法捕获手势 https://stackoverflow.com/questions/4027553/android-gesturedetector-wont-catch-gestures

另外，这是结果：

解决办法其实就是重写onDown方法并返回true；否则手势检测器将停止并且不会检测到向上：

        final GestureDetector gesture = new GestureDetector(getActivity(),
            new GestureDetector.SimpleOnGestureListener() {

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

                @Override
                public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                    float velocityY) {
                    Log.i(Constants.APP_TAG, "onFling has been called!");
                    final int SWIPE_MIN_DISTANCE = 120;
                    final int SWIPE_MAX_OFF_PATH = 250;
                    final int SWIPE_THRESHOLD_VELOCITY = 200;
                    try {
                        if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                            return false;
                        if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
                            && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                            Log.i(Constants.APP_TAG, "Right to Left");
                        } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
                            && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                            Log.i(Constants.APP_TAG, "Left to Right");
                        }
                    } catch (Exception e) {
                        // nothing
                    }
                    return super.onFling(e1, e2, velocityX, velocityY);
                }
            });

        v.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return gesture.onTouchEvent(event);
            }
        });