您如何制作没有UI的应用程序，所以当您打开它时，它将运行一些代码

Question

I am making a simple app that, when opened, checks what the media volume. If it is more than zero, sets it to 0 and when it is equal to zero, sets it to 100%. (I'm gonna remap the bixby button). My problem is is that when I open the app, it opens a blank UI, like this: https://i.imgur.com/d9NkFX0.png And I don't want it to.

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        AudioManager am = (AudioManager) getSystemService(AUDIO_SERVICE);
        int volume_level= am.getStreamVolume(AudioManager.STREAM_MUSIC);
        if (volume_level > 0)
        {
            am.setStreamVolume(
                    AudioManager.STREAM_MUSIC,
                    volume_level,
                    0);
        }
        else {
            am.setStreamVolume(
                    AudioManager.STREAM_MUSIC,
                    volume_level,
                    100);
        }
    }

Also it kinda doesn't work at all.

Answer 1

You are opening an activity. This will remain open until you exit it.

Try adding a finish() at the end of onCreate()