Service (bindService音乐播放器)

Service (bindService音乐播放器)

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音乐服务

public class MusicService extends Service {

    @Override
    public IBinder onBind(Intent intent) {
        return new MusicController();
    }

    /**
     * Binder是IBinder接口实现类
     * MusicController实现了接口MusicControllerInterface
     * 接口MusicControllerInterface中有两个抽象方法
     */
    class MusicController extends Binder implements MusicControllerInterface {

        @Override
        public void play() {
            MusicService.this.play();
        }

        @Override
        public void pause() {
            MusicService.this.pause();
        }

    }

    public void play() {
        System.out.println("音乐开始播放");
    }

    public void pause() {
        System.out.println("音乐暂停播放");
    }
}

音乐控制接口

public interface MusicControllerInterface {
    void play();
    void pause();
}

Activity中使用服务

public class MainActivity extends Activity {

    MusicControllerInterface mci;

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

        Intent intent = new Intent(this, MusicService.class);
        MusicConnection conn = new MusicConnection();

        // 混合启动
        // start是为了让进程变成服务进程
        startService(intent);
        // 绑定服务是为了拿到中间人对象
        bindService(intent, conn, BIND_AUTO_CREATE);
    }

    class MusicConnection implements ServiceConnection {

        // 服务连接建立时，此方法调用。
        // 当MusicService类中的方法onBind()返回IBinder中间人对象时，MusicConnection类的onServiceConnected()方法会自动被调用
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            mci = (MusicControllerInterface) service;
        }

        // 失去服务连接时调用
        @Override
        public void onServiceDisconnected(ComponentName name) {

        }

    }

    public void play(View v) {
        mci.play();
    }

    public void pause(View v) {
        mci.pause();
    }

}