使CAMERA ON和CAMERA OFF Toast消息

Question

通过注册BroadcastReceiver，当设备屏幕被打开/关闭时，我可以获得SCREEN ON和SCREEN OFF toast消息。以同样的方式，当点击设备相机按钮时，我可以获得CAMERA ON和CAMERA OFF Toast消息吗？

我使用以下源代码来获取SCREEN ON / OFF toast消息。

public class MainActivity extends Activity {

BroadcastReceiver mybroadcast = new BroadcastReceiver() {

    // When Event is published, onReceive method is called
    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        Log.i("[BroadcastReceiver]", "MyReceiver");

        if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
            Log.i("[BroadcastReceiver]", "Screen ON");
            Toast.makeText(getApplicationContext(), "SCREEN ON",Toast.LENGTH_LONG).show();
        } else if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
            Log.i("[BroadcastReceiver]", "Screen OFF");
            Toast.makeText(getApplicationContext(), "SCREEN OFF",Toast.LENGTH_LONG).show();
        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    registerReceiver(mybroadcast, new IntentFilter(Intent.ACTION_SCREEN_ON));
    registerReceiver(mybroadcast, new IntentFilter(Intent.ACTION_SCREEN_OFF));
}