1普通的控件,buttom,Textview。。。。
PRivate LinearLayout mLayout; private Button mButton; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mLayout = (LinearLayout) this.findViewById(R.id.mylayout); mButton = (Button) this.findViewById(R.id.my_btn); mLayout.setOnTouchListener(this); mButton.setOnTouchListener(this); mLayout.setOnClickListener(this); mButton.setOnClickListener(this); } @Override public void onClick(View v) { Log.i("lyf", "OnClickListener--onClick--" + v); } //public static final int ACTION_DOWN = 0; //public static final int ACTION_UP = 1; //public static final int ACTION_MOVE = 2; @Override public boolean onTouch(View v, MotionEvent event) { Log.i("lyf", "OnTouchListener--onTouch-- action=" + event.getAction() + " --" + v); return false; }情景1、可以看到我们onTouch方法返回false,不消费该事件,往下层传递。
I/lyf: OnTouchListener--onTouch-- action=0 --android.widget.Button I/lyf: OnTouchListener--onTouch-- action=2 --android.widget.ButtonI/lyf: OnTouchListener--onTouch-- action=2 --android.widget.ButtonI/lyf: OnTouchListener--onTouch-- action=2 --android.widget.ButtonI/lyf: OnTouchListener--onTouch-- action=2 --android.widget.Button I/lyf: OnTouchListener--onTouch-- action=1 --android.widget.ButtonI/lyf: OnClickListener--onClick--android.widget.Button情景2、在onTouch方法返回true,消费该事件,不往下层传递了。onClick方法自然而然也没有接收到信息了,至于为什么不传递到onClick方法里面,我们来看看源码就知道了:
if (!mHasperformedLongPress) { // This is a tap, so remove the longpress check removeLongPressCallback(); // Only perform take click actions if we were in the pressed state if (!focusTaken) { // Use a Runnable and post this rather than calling // performClick directly. This lets other visual state // of the view update before click actions start. *if (mPerformClick == null) { mPerformClick = new PerformClick(); } if (!post(mPerformClick)) { performClick(); } }* }performClick()这个方法就是关于点击事件的,而这个方法是在onTouchEvent方法里面,而 onTouch方法又优先于onTouchEvent方法,那再看看为什么onTouch优先于onTouchEvent吧! public boolean dispatchTouchEvent(MotionEvent event){ ... ... if(onFilterTouchEventForSecurity(event)){ ListenerInfo li = mListenerInfo; if(li != null && li.mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED && li.mOnTouchListener.onTouch(this, event)) { return true; } if(onTouchEvent(event)){ return true; } } ... ... return false; }li.mOnTouchListener.onTouch()这个方法就在分发事件中调用, 为什么onTouch方法执行优先于onTouchEvent,跟踪源码:很明显可以看到,事件的传递,会优先掉用mOnTouchListener.onTouch(this, event)这个方法,然后才能轮到onTouchEvent(event)获取事件,顺序如此,有什么可说。既然说到这里,我们也应该想起了onClick和onLongPressClic都是对onTouchEvent(event)的依赖,如果在setOnTouchListener.onTouch()的时候返回true,那么onTouchEvent方法不会被调用。同样,内置诸如click事件的实现等等都基于onTouchEvent,假如onTouch返回true,这些事件将不会被触发。因为有3个判断满足的情况下,就不会进入onTouchEvent了,只有不满足的情况下才会进入。I/lyf: OnTouchListener--onTouch-- action=0 --android.widget.ButtonI/lyf: OnTouchListener--onTouch-- action=2 --android.widget.ButtonI/lyf: OnTouchListener--onTouch-- action=2 --android.widget.ButtonI/lyf: OnTouchListener--onTouch-- action=1 --android.widget.Button最后,在这里总结一点,上面2个列子,onTouch-onClick,如果消费了,点击就没有效果了。
2自定义一个控件来实现dispatchTouchEvent(触摸事件分发)、onTouchEvent(触摸事件)、在Activity中实现onTouch方法和onClick方法。在这里我只是记录一下事件分发的日志,以方便日后不用每次的测试一下。
情景1;
public class TestButton extends Button { ........................... @Override public boolean dispatchTouchEvent(MotionEvent event) { Log.i("lyf", "dispatchTouchEvent-- action=" + event.getAction()); return super.dispatchTouchEvent(event); } @Override public boolean onTouchEvent(MotionEvent event) { Log.i("lyf", "onTouchEvent-- action="+event.getAction()); return super.onTouchEvent(event); }}public class ListenerActivity extends Activity implements View.OnTouchListener, View.OnClickListener { ................................ @Override public boolean onTouch(View v, MotionEvent event) { Log.i("lyf", "OnTouchListener--onTouch-- action=" + event.getAction() + " --" + v); return false; } @Override public void onClick(View v) { Log.i("lyf", "OnClickListener--onClick--" + v); }}结果: “ I/lyf: dispatchTouchEvent– action=0 I/lyf: onTouch– action=0 I/lyf: onTouchEvent– action=0 I/lyf: dispatchTouchEvent– action=2 I/lyf: onTouch– action=2 I/lyf: onTouchEvent– action=2 I/lyf: dispatchTouchEvent– action=1 I/lyf: onTouch– action=1 I/lyf: onTouchEvent– action=1 I/lyf: onClick–com.example.xiaolin.mytochuview.TestButton
可以看到事件分发由上车到下车,中途没有乘客,哈哈,不知道这样说对不对了!,写到这里就不写了,大家可以自行修改值,来看看结果,中途可以上车,也可以下车,。。最后,重点,返回值,@Overridepublic boolean dispatchTouchEvent(MotionEvent event) { Log.i("lyf", "dispatchTouchEvent-- action=" + event.getAction()); return true;}再看一下结果:com.example.xiaolin.mytochuview I/lyf: dispatchTouchEvent– action=0 com.example.xiaolin.mytochuview I/lyf: dispatchTouchEvent– action=2 com.example.xiaolin.mytochuview I/lyf: dispatchTouchEvent– action=2 com.example.xiaolin.mytochuview I/lyf: dispatchTouchEvent– action=2 com.example.xiaolin.mytochuview I/lyf: dispatchTouchEvent– action=2 com.example.xiaolin.mytochuview I/lyf: dispatchTouchEvent– action=1 “` 返回值为true,不再往下传递了(消费了该事件),false(没有消费该事件)!
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