Android中onTouch與onClick事件的關系

這幾天遇到點關於Android的觸摸事件相關的，還跟onClick有關，暫且記下：

LinearLayout分別設置了onTouchListener，onClickListener，onLongClickListener及onTouchEvent回調

1、在屏幕上觸摸之後基本的執行流程如下：

onTouch,action=0
onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1
onClick

也就是先說onTouchListener是最先被觸發的，然後是本身的onTouchEvent回調；當最後的up事件發生並被onTouchEvent處理後才會觸發onClickListener。

2、把onTouchEvent回調中的super.onTouchEvent去除，直接返回true；則流程如下：

onTouch,action=0
onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1

可以看到onClickListener永遠無法被觸發，也側面說明了對onClick的觸發是在onTouchEvent回調中來實現的。

3、長按屏幕，流程如下：

onTouch,action=0
onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onLongClick
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1
onClick

當長按的時候，無需到up就會觸發onLongClick的響應，但之後也會繼續觸發onClick的響應。

4、但如果在onLongClick中返回true，則流程如下，即只在中間觸發了onLongClick，之後會繼續響應touch，但當up的時候就不會再觸發onClick

onTouch,action=0

onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onLongClick
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1

測試代碼如下：

public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FrameLayout frame = (FrameLayout)findViewById(R.id.container);
        LinearLayoutTest line = new LinearLayoutTest(this);
        line.setOnClickListener(new ClickListener());
        line.setOnLongClickListener(new LongClickListener());
        line.setOnTouchListener(new TouchListener());
        line.setLongClickable(true);
        frame.addView(line);
    }
    public class ClickListener implements OnClickListener {
        @Override
        public void onClick(View v) {
            Log.e("test","onClick");
        }
    }
    public class LongClickListener implements OnLongClickListener{
        @Override
        public boolean onLongClick(View v) {
            Log.e("test","onLongClick");
            return true;
        }
    }
    public class TouchListener implements OnTouchListener{
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            Log.e("test","onTouch,action="+event.getAction());
            return false;
        } 
    }        
}

public class LinearLayoutTest extends LinearLayout{
    public LinearLayoutTest(Context context) {
        super(context);
    }
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        Log.e("test","onTouchEvent,action="+event.getAction());
        return super.onTouchEvent(event);
    }
}