我要评论前三章讲了KeyEvent事件在默认情况下的执行顺序、改变View层和ViewGroup分发逻辑对KeyEvent事件分发的影响，本章讲得是改变Activity对KeyEvent事件的影响
先修改activity的dispatchTouchEvent的返回值为true
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
switch (event.getAction()){
case KeyEvent.ACTION_DOWN:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"dispatchKeyEvent_ACTION_DOWN");
return true;
case KeyEvent.ACTION_UP:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"dispatchKeyEvent_ACTION_UP");
break;
}
return super.dispatchKeyEvent(event);
}
执行结果
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_ViewGroup1: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: onKeyUp_ACTION_UP
com.example.keytest I/wangjiasheng_MainActivity: onKeyUp_ACTION_UP
再将dispatchTouchEvent的返回值改为false
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
switch (event.getAction()){
case KeyEvent.ACTION_DOWN:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"dispatchKeyEvent_ACTION_DOWN");
return false;
case KeyEvent.ACTION_UP:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"dispatchKeyEvent_ACTION_UP");
break;
}
return super.dispatchKeyEvent(event);
}
执行结果
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_ViewGroup1: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: onKeyUp_ACTION_UP
com.example.keytest I/wangjiasheng_MainActivity: onKeyUp_ACTION_UP
上面是修改dispatchTouchEvent的返回值情况，下面看修改onKeyDown的返回值情况，先将返回值修改为true
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
switch (event.getAction()){
case KeyEvent.ACTION_DOWN:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"onKeyUp_ACTION_DOWN");
return true;
case KeyEvent.ACTION_UP:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"onKeyUp_ACTION_UP");
break;
}
return super.onKeyUp(keyCode, event);
}
返回值情况
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_ViewGroup1: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_MyView: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_MyView: onKeyDown_ACTION_DOWN
com.example.keytest I/wangjiasheng_MainActivity: onKeyDown_ACTION_DOWN
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_ViewGroup1: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: onKeyUp_ACTION_UP
com.example.keytest I/wangjiasheng_MainActivity: onKeyUp_ACTION_UP
再将返回值修改为false
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
switch (event.getAction()){
case KeyEvent.ACTION_DOWN:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"onKeyUp_ACTION_DOWN");
return false;
case KeyEvent.ACTION_UP:
Log.i("wangjiasheng_"+this.getClass().getSimpleName(),"onKeyUp_ACTION_UP");
break;
}
return super.onKeyUp(keyCode, event);
}
返回值情况
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_ViewGroup1: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_MyView: dispatchKeyEvent_ACTION_DOWN
com.example.keytest I/wangjiasheng_MyView: onKeyDown_ACTION_DOWN
com.example.keytest I/wangjiasheng_MainActivity: onKeyDown_ACTION_DOWN
com.example.keytest I/wangjiasheng_MainActivity: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_ViewGroup1: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: dispatchKeyEvent_ACTION_UP
com.example.keytest I/wangjiasheng_MyView: onKeyUp_ACTION_UP
com.example.keytest I/wangjiasheng_MainActivity: onKeyUp_ACTION_UP
此章总结
当dispathTouchEvent返回值为true的情况，事件将被丢弃，不会执行activity和所有View层的onKeyDown和onKeyUp，事件不会向上传递也不会向下传递，
当onKeyDown返回值为true和false是对执行结果不影响
本文地址：https://blog.csdn.net/w13635739860/article/details/107560209
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