Android MediaPlayer 停止()不起作用

Question

差不多是标题。使用 ListView，在单击一个项目时，合适的原始文件 ID 将传递给 playsound 方法。 start() 工作正常，但 stop() 不执行任何操作。

public class AmbienceActivity extends AppCompatActivity {

    private MediaPlayer sound;

    ListView list;
    String[] web = {
            "Breeze",
            "Birds Chirping",
            "Rain on Window",
            "Cafe"
    };
    Integer[] imageId = {
            R.mipmap.ic_launcher_round,
            R.mipmap.ic_launcher_round,
            R.mipmap.ic_launcher_round,
            R.mipmap.ic_launcher_round
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ambience);

        SoundsList adapter = new SoundsList(AmbienceActivity.this, web, imageId);
        list = (ListView) findViewById(R.id.soundslist);
        list.setAdapter(adapter);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                if(position==0)
                    playSound(R.raw.breeze);
                else if(position==1)
                    playSound(R.raw.birds_chatter);
                else if(position==2)
                    playSound(R.raw.rain_on_window);
                else if(position==3)
                    playSound(R.raw.cafe_chatter);
            }
        });
    }

        protected void playSound ( int x){
            int soundPlaying = 0;
            sound = MediaPlayer.create(this,x);
            if (x != soundPlaying && sound != null) { //Play a new sound
                sound.release();
                sound = null;
                sound = MediaPlayer.create(this, x);
            } else { //Play sound
                sound = MediaPlayer.create(this, x);
            }

            if (sound != null && !sound.isPlaying()) {
                sound.start();
            } else if (sound != null && sound.isPlaying()) {
                sound.stop();
            }

            soundPlaying = x;
        }
    }

playing 变量在 Activity 的 main 方法中被初始化为零(onItemClick 是其中的一部分)。

Answer 1

每次调用 playSound() 方法时，您都在创建一个 MediaPlayer 实例，这是不正确的，这基本上就是问题所在，请执行以下操作:

private MediaPlayer sound;
protected void playSound (int x){
    //MediaPlayer sound = MediaPlayer.create(this,x);
    if(sound != null){
         sound.release();
         sound = null;
         sound = MediaPlayer.create(this,x);
    }
    ...
    ...
}

现在，你不需要一个变量来检测 MediaPlayer 是否正在播放，使用方法 isPlaying() 然后如果它正在播放就停止 停止():

private MediaPlayer sound;

protected void playSound (int x){
    int soundPlaying = 0;
    //MediaPlayer sound = MediaPlayer.create(this,x);

    if(x != soundPlaying && sound != null){ //Play a new sound
        sound.release();
        sound = null;
        sound = MediaPlayer.create(this,x);
    }else{ //Play sound
        sound = MediaPlayer.create(this,x);
    }

    if(sound != null && !sound.isPlaying()) {
        sound.start();
        //playing = 1;

    } else if(sound != null && sound.isPlaying()){
        sound.stop();
        // playing = 0;
    }

    soundPlaying = x; //current id of sound.
}