日志表现出：startFling()方法先后在onFling()和onTouch()调用。按照逻辑来说，在onFling()中调用了，即使在onTouch()方法中调用也不会再执行。

11-01 16:09:55.147: D/WatchTvFragment(1026): ++programTouchListener.onTouch++11-01 16:09:55.147: D/WatchTvFragment(1026): ++onFling++11-01 16:09:55.147: D/WatchTvFragment(1026): velocityX:139.54526, velocityY:225.460211-01 16:09:55.147: D/WatchTvFragment(1026): onFling() set bFlinging to true11-01 16:09:55.147: D/WatchTvFragment(1026): onFling() invode startFling()11-01 16:09:55.147: D/WatchTvFragment(1026): ++startFling++11-01 16:09:55.147: D/WatchTvFragment(1026): event.getAction():111-01 16:09:55.147: D/WatchTvFragment(1026): onTouch() set bFlinging to true11-01 16:09:55.147: D/WatchTvFragment(1026): onTouch() invode startFling()11-01 16:09:55.147: D/WatchTvFragment(1026): ++startFling++11-01 16:09:55.197: D/WatchTvFragment(1026): run() set bFlinging to false11-01 16:09:55.247: D/WatchTvFragment(1026): run() set bFlinging to false

经过处理，startFling()方法不会既执行onFling()方法的调用又去执行onTouch()方法的调用。

在onTouch()方法中的相关代码片段如下

case MotionEvent.ACTION_UP:Logger.i(TAG, "event.getAction():" + MotionEvent.ACTION_UP);programWidth = programListFragment.getView().getMeasuredWidth();float velocityX = (programParams.leftMargin < programWidth / 2) ? -1000 : 1000;Logger.i(TAG, "onTouch() invode startFling()");startFling(velocityX);break;

在onFling()方法中的相关代码片段如下

public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {    Logger.i(TAG, "++onFling++");    Logger.i(TAG, "velocityX:" + velocityX + ", velocityY:" + velocityY);    Logger.i(TAG, "onFling() invode startFling()");    startFling(velocityX);    return true; // 需要返回true}

方法startFling()的代码片段如下

boolean bFlinging = false;void stopFling() {    bFlinging = false;}synchronized void startFling(final float velocityX) {    Logger.i(TAG, "++startFling++");    if (bFlinging) {        Logger.i(TAG, "invalid operation.");        return;    }    Logger.i(TAG, "flinging...");    bFlinging = true;    programWidth = programListFragment.getView().getMeasuredWidth();    new Thread() {        public void run() {            int interval = 50;            float xDistFling;            int newLeftMargin;            float decay = 0.98f;            float v;            // 速度从(+/-)1000px/s开始。            if (velocityX > 0 && velocityX < 1000)                v = 1000;            else if (velocityX < 0 && velocityX > -1000)                v = -1000;            else                v = velocityX;            // running表示while循环什么时候结束            boolean running = true;            while (running) {                v *= decay;                xDistFling = v / 1000 * interval;                newLeftMargin = programParams.leftMargin + (int) xDistFling;                if (newLeftMargin <= 0) {                    newLeftMargin = 0;                    running = false;                } else if (newLeftMargin >= channelWidth) {                    newLeftMargin = channelWidth;                    running = false;                }                programParams.leftMargin = newLeftMargin;                try {                    Thread.sleep(interval);                } catch (InterruptedException e) {                    e.printStackTrace();                }                handler.sendEmptyMessage(0);            }            Logger.i(TAG, "flinging finished.");        }    }.start();}

打印出来的日志表现是符合逻辑的，日志如下。

（1）onFling()中执行startFling()方法，在onTouch()中再执行被视为无效操作。

11-01 16:30:29.427: D/WatchTvFragment(2654): ++programTouchListener.onTouch++11-01 16:30:29.427: D/WatchTvFragment(2654): ++onFling++11-01 16:30:29.427: D/WatchTvFragment(2654): velocityX:-348.25256, velocityY:215.8674811-01 16:30:29.427: D/WatchTvFragment(2654): onFling() invode startFling()11-01 16:30:29.427: D/WatchTvFragment(2654): ++startFling++11-01 16:30:29.427: D/WatchTvFragment(2654): flinging...11-01 16:30:29.427: D/WatchTvFragment(2654): event.getAction():111-01 16:30:29.427: D/WatchTvFragment(2654): onTouch() invode startFling()11-01 16:30:29.427: D/WatchTvFragment(2654): ++startFling++11-01 16:30:29.427: D/WatchTvFragment(2654): invalid operation.11-01 16:30:29.987: D/WatchTvFragment(2654): flinging finished.

（2）onFling()中没有执行startFling()方法，在onTouch()中可以执行。

11-01 17:30:52.257: D/WatchTvFragment(8850): ++programTouchListener.onTouch++11-01 17:30:52.257: D/WatchTvFragment(8850): event.getAction():111-01 17:30:52.257: D/WatchTvFragment(8850): onTouch() invode startFling()11-01 17:30:52.257: D/WatchTvFragment(8850): ++startFling++11-01 17:30:52.257: D/WatchTvFragment(8850): flinging...11-01 17:30:52.307: D/WatchTvFragment(8850): flinging finished.