电视按键事件的处理(4)

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