创建一个基本活动，并扩展该基本活动中的所有其他活动，并播放bg音乐或您想要的任何内容

create a base activity and extend all other other activities from base activity and play bg music or whatever you want

public class BaseActivty extends AppCompatActivity{

@Override
    protected void onPause() {
        super.onPause();
// pause music
    }

@Override
    protected void onResume() {
        super.onResume();
// play music
    }
}

public class FirstActivty extends BaseActivty{

// perform other stuff here
}

希望对您有帮助...

hope that will help you...