GestureDetector 手势监听类小记

1、常规的点击滑动的事件处理
设置一些监听器、如button、seekBar 等的onClickListener() onScrollLisrener() onLongClickListener() setOnKeyListener()等等。。。。可以进行一些常规的 点击事件的处理。

2、当我们进行一些复杂的手势 处理的时候 常规的监听器就不够用了
我们可以通过MotionEvent的getAction()方法来获取Touch事件的类型，包括 ACTION_DOWN（按下触摸屏）, ACTION_MOVE（按下触摸屏后移动受力点）, ACTION_UP（松开触摸屏）和ACTION_CANCEL（不会由用户直接触发）。借助对于用户不同操作的判断，结合getRawX()、getRawY()、getX()和getY()等方法来获取坐标后进行判断处理。

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3）使用GestureDetector类来处理 手势

private GestureDetector mGestureDetector = new GestureDetector(getApplicationContext(), mGestureListener);

private GestureDetector.SimpleOnGestureListener mGestureListener = new GestureDetector.SimpleOnGestureListener() {
    @Override
    public boolean onDown(MotionEvent e) {
        L.i("mGestureListener onDown");
        onDownHasDone = false;
        if (idIncludeHkList.getVisibility() == View.VISIBLE) {
            idIncludeHkList.setVisibility(View.INVISIBLE);
            onDownHasDone = true;
            return true;
        }
        if (idPlayChatLl.getVisibility() == View.VISIBLE) {
            dismissChat();
            onDownHasDone = true;
            return true;
        }
        if (webView.getVisibility() == View.VISIBLE) {
            lastLp = (RelativeLayout.LayoutParams) idIvVp.getLayoutParams();
        }
        return super.onDown(e);
    }

    @Override
    public void onLongPress(MotionEvent e) {
        super.onLongPress(e);
        if (Constant.DEBUG)
            L.i("长按");
        if (webView.getVisibility() != View.VISIBLE) {
            otherView.setVisibility(otherView.getVisibility() == View.VISIBLE ? View.INVISIBLE : View.VISIBLE);
            idPlayGxbTb.setText("");
        }
    }

    @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
        if (webView.getVisibility() == View.VISIBLE) {
            disWebView();
            return true;
        } else {
            if (curView instanceof RelativeLayout && notPlay) {
                return true;
            } else {
                if (notPlay && idPlayRestartIv != null && idPlayRestartIv.getVisibility() != View.VISIBLE
                        && idPlayBufferRl != null && idPlayBufferRl.getVisibility() != View.VISIBLE) {
                    showPlayRestartIv();
                }
            }
        }
        return super.onSingleTapConfirmed(e);
    }

    @Override
    public boolean onScroll(MotionEvent event1, MotionEvent event2, float distanceX, float distanceY) {
        if (event1 == null || event2 == null) {
            return super.onScroll(event1, event2, distanceX, distanceY);
        }
        if (webView.getVisibility() == View.VISIBLE) {
            float mx = event2.getRawX() - event1.getRawX();
            float my = event2.getRawY() - event1.getRawY();
            if (mx == 0 && my == 0) {
                return super.onScroll(event1, event2, distanceX, distanceY);
            }
            pointC = 1;
            L.i(String.format(Locale.CHINA, "mGestureListener onScroll distanceX = %f,distanceY = %f,mx = %f,my = %f", distanceX, distanceY, mx, my));
            if (lastLp == null) {
                L.i("mGestureListener lastLp == null");
                lastLp = (RelativeLayout.LayoutParams) idIvVp.getLayoutParams();
            }
            moveView(idPlVv, lastLp.rightMargin - (int) mx, lastLp.bottomMargin - (int) my);
            moveView(idIvVp, lastLp.rightMargin - (int) mx, lastLp.bottomMargin - (int) my);
        } else if (direction == 0) {
            if (ViewUtil.inRangeOfView(idPlayChatContentLv, event1)) {
                direction = 3;
            } else {
                float a = Math.abs(distanceY);
                float b = Math.abs(distanceX);
                if (a > b) {
                    direction = 1;  // 上下滑动
                } else if (b > a) {
                    direction = 2;  // 左右滑动
                }
            }
        }
        return super.onScroll(event1, event2, distanceX, distanceY);
    }

    @Override
    public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) {
        L.i("onFling");
        if (event1 == null || event2 == null) {
            return super.onFling(event1, event2, velocityX, velocityY);
        }
        final int FLING_MIN_DISTANCE = 100, FLING_MIN_VELOCITY = 200;
        int my = (int) (event2.getY() - event1.getY());
        if (event1.getX() - event2.getX() > FLING_MIN_DISTANCE
                && Math.abs(velocityX) > FLING_MIN_VELOCITY) {
            // Fling left
            L.d("Fling left");
            // 播放视频的时候调节音量 可以在这里调用方法
        } else if (event2.getX() - event1.getX() > FLING_MIN_DISTANCE
                && Math.abs(velocityX) > FLING_MIN_VELOCITY) {
            // Fling right
            L.d("Fling rigth");
         
        } else if (event2.getY() - event1.getY() > FLING_MIN_DISTANCE
                && Math.abs(velocityY) > FLING_MIN_VELOCITY) {
            if (direction == 1 && !onDownHasDone) {
                // Fling down
                L.d("Fling down");
            }
        } else if (event1.getY() - event2.getY() > FLING_MIN_DISTANCE
                && Math.abs(velocityY) > FLING_MIN_VELOCITY) {
            if (direction == 1 && !onDownHasDone) {
                // Fling up
                L.d("Fling up");
            }
        }
        return false;
    }
};
public boolean onTouchEvent(MotionEvent event) {   
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        pointC = 0;
        direction = 0;
    }
    int pointCount = event.getPointerCount();
    if (pointCount == 1) {    // 单一手指在屏幕上时候
        if (pointC != 2)
            return mGestureDetector.onTouchEvent(event);
    } else {
        if (pointC != 1)       // 这里是缩放
            return mScaleGestureDetector.onTouchEvent(event);
    }
    return super.onTouchEvent(event);
}

另外:在布局中如果有其他需要滑动的控件 例如viewpager 需要etOnTouchListener(listener); 否则可能滑动会失效。因为在上面将触摸事件重写了。
View.OnTouchListener listener = new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
return onTouchEvent(event);
}
};
ps: 在手势检测中，onFling()与onScroll()有点类似，一个为“滑动”，一个为“拖动”。都是手指在屏幕（或某一组件）上移动一段距离后触发。
onFling（）为“滑动”的最后触发（即手指Up抬起时触发），需要较为快速的"滑动"操作（但在"滑动"过程中，也会不停的触发onScroll（）），如果慢速滑动，最后没有调用onFling()。
onScroll（）为“拖动”或“滑动”的过程中不断触发,直到动作结束，无论快慢都会触发。