java - 在 Activity 之间停止和播放 MediaPlayer

Question

我有这 3 个类，即 MainActivity、Options 和 Play。当用户单击选项按钮时，用户可以决定他/她是否想要播放音频。但默认情况下，尽管用户不会单击“选项”上的按钮，但仍会播放音频。

我在 StackOverflow 中找到了一些代码，但是如果用户在决定播放音频后决定停止音频，我不知道如何停止音频。 (再次进入选项)

这是到目前为止的代码:

MainActivity.class(选项)

public class MainActivity extends Activity {

    public MediaPlayer mp = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button b = (Button) findViewById(R.id.button1);
        b.setOnClickListener(new OnClickListener() {

                @Override
            public void onClick(View v) {
                Intent a = new Intent(MainActivity.this, Play.class);
                startActivity(a);



            }

        });
    }
}

Play.java

public class Play extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.play);

        Button back = (Button) findViewById (R.id.button1);

        back.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent menu = new Intent (getApplicationContext(), Menu.class);
                startActivity(menu);
            }

        });


    MainActivity z = new MainActivity();
    MediaPlayer mp  = z.mp;

    if (mp == null) {
        mp = MediaPlayer.create(Play.this, R.raw.math_game);
        mp.start();
    }

    else if (mp.isPlaying()) {
        mp.stop();
        mp = null;
    }
    }

}

和主菜单

public class Menu extends Activity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.menu);

        Button play, opt;
        play = (Button) findViewById (R.id.play);
        opt = (Button) findViewById (R.id.opt);

        play.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent play = new Intent (Menu.this, Play.class);
                startActivity(play);
            }


        });

        opt.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent play = new Intent (Menu.this, MainActivity.class);
                startActivity(play);
            }


        });     
    }

}

谢谢:))

Answer 1

查看 Android Activity 生命周期 ( http://developer.android.com/training/basics/activity-lifecycle/index.html )，您会发现有更多 Activity 覆盖。即 onPause、onResume、onStop 和 onDestroy。我想您会想在 Play Activity 的 onPause 中停止音乐。