媒体播放器在准备服务时如何添加加载对话框（Android）

Question

我建立了应用程序来播放来自互联网的音频，我使用服务在后台播放音频，问题是如何在媒体播放器准备服务（背景）时使用我的代码来显示loding对话框。

活动

package com.uqifm.onlineradio;
.......
public class MainActivity extends AppCompatActivity {

    Button b_play;
    Boolean started = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_NO_TITLE);

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        b_play = (Button) findViewById(R.id.b_play);

        b_play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(started){
                    started = false;
                    stopService(new Intent(MainActivity.this,MyService.class));
                    b_play.setText("PLAY");
                }else{
                    started = true;
                    startService(new Intent(MainActivity.this,MyService.class));
                    b_play.setText("STOP");
                }
            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        stopService(new Intent(MainActivity.this,MyService.class));
    }
}

服务

package com.uqifm.onlineradio;
....................
public class MyService extends Service {

    MediaPlayer mediaPlayer;
    String stream = "http://xxxxx:36365";

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

    @Override
    public void onCreate() {
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        try {
            mediaPlayer.setDataSource(stream);
            mediaPlayer.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        mediaPlayer.start();
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        mediaPlayer.release();
    }
}

Answer 1

注册广播，在开始服务之前启动404。然后等待广播。广播后，隐藏对话框。请参阅此主题中的示例。 Send data from Service back to my activity

Answer 2

将ProgressDialog放在xml中，并根据您的要求设置可见性。使用界面与服务进行通信。

Answer 3

您可以使用Broadcast或尝试EventBus，这样更容易。您可以使用EventBus在服务中发布活动，并在MainActivity中接收广播并更新进度对话框。
Please follow the link.

Answer 4

也许是这样的：

    fun playAudio(audioUrl: String){
    showProgressBar()
    var mediaPlayer: MediaPlayer? = MediaPlayer().apply {
        setAudioStreamType(AudioManager.STREAM_MUSIC)
        setDataSource(audioUrl)
        prepareAsync() // might take long! (for buffering, etc)

    }
    mediaPlayer?.setOnPreparedListener {
        hideProgressBar()
        it.start()
    } 
    mediaPlayer?.setOnCompletionListener {
        mediaPlayer.release()
    } 
}