How to capture app switch key using onKeyDown in Android?

问题

I am trying to capture app switch key and home key on android 3.1 and 4.0 but it doesn't seem like its working.

here is what I am doing

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
   if (KeyCode == KeyEvent.KEYCODE.KEYCODE_APP_SWITCH && event.getRepeatCount() == 0)
    { 
        Log.d ("onkeydown","app switch key");
    }
   else if (KeyCode == KeyEvent.KEYCODE.KEYCODE_HOME && event.getRepeatCount() == 0)
    { 
        Log.d ("onkeydown","home key");
    }
    //EDIT:
    return super.onKeyDown(keyCode, event);
}

My log.d statement is not printed. Is it possible to capture these 2 keys?

updated code with correct return statement

回答1:

Um.

Well, no, you can't.

public static final int KEYCODE_HOME

Since: API Level 1

Key code constant: Home key.

This key is handled by the framework and is never delivered to applications.

http://developer.android.com/reference/android/view/KeyEvent.html

回答2:

It can be achieved using reflection.

It is under class android.os.ServiceManager having an aidl com.android.internal.statusbar.IStatusBarService and it contains toggleRecentApps method

And also try this method here

回答3:

The super.onKeyDown(keyCode, event) is missing, i think you should try this:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
super.onKeyDown(keyCode, event);

   if (KeyCode == KeyEvent.KEYCODE.KEYCODE_APP_SWITCH && event.getRepeatCount() == 0)
    { 
        Log.d ("onkeydown","app switch key");
    }
   else if (KeyCode == KeyEvent.KEYCODE.KEYCODE_HOME && event.getRepeatCount() == 0)
    { 
        Log.d ("onkeydown","home key");
    }
    return true;
}

Doing the same using switch statement:

@Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
    super.onKeyDown(keyCode, event);
        switch(keyCode)
        {
            case KeyEvent.KEYCODE_CAMERA:
             Toast.makeText(ListViewActivity.this, "Pressed Camera Button", Toast.LENGTH_SHORT).show();
                return true;
            case KeyEvent.KEYCODE_1:
             Toast.makeText(ListViewActivity.this, "Pressed 1", Toast.LENGTH_SHORT).show();
                return true;
            case KeyEvent.KEYCODE_HOME:
             Toast.makeText(ListViewActivity.this, "Pressed Home Button", Toast.LENGTH_SHORT).show();
                return true;

            case KeyEvent.KEYCODE_BACK:
             Toast.makeText(ListViewActivity.this, "Pressed Back Button", Toast.LENGTH_SHORT).show();
                finish();
                return true;
        }

        return false;
    }

来源：https://stackoverflow.com/questions/8579818/how-to-capture-app-switch-key-using-onkeydown-in-android

标签

android

onkeydown