只有在自动启动时才能听到视频（Android 2.3.5）

Question

我有以下情况；如果我转到我的 PlayerActivity（由 SurfaceView 和自定义媒体播放器组成）并尝试通过触发连接到我的 xml 的播放按钮的方法 playAudio(View v) 在 onCreate 的末尾自动启动视频，视频开始，但只能听到，看不到图像。如果我没有自动启动它，我按下播放按钮，视频播放没有问题。

onCreate

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

    targetUri = this.getIntent().getData();

    context = this;

    audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    currentVolume = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);

    audioPlayer = (RelativeLayout) findViewById(R.id.audio_player);
    playButton = (Button) findViewById(R.id.playButton);
    pauseButton = (Button) findViewById(R.id.pauseButton);
    stopButton = (ImageView) findViewById(R.id.stopButton);
    seekbar = (SeekBar) findViewById(R.id.seekBarPlayer);
    runningTime = (TextView) findViewById(R.id.audioRunningTime);
    totalTime = (TextView) findViewById(R.id.audioTotalTime);

    getWindow().setFormat(PixelFormat.UNKNOWN);
    surfaceView = (SurfaceView) findViewById(R.id.surfaceview);
    surfaceHolder = surfaceView.getHolder();
    surfaceHolder.addCallback(this);
    surfaceHolder.setFixedSize(176, 144);
    surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

    surfaceView.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // Make video controls appear / disappear
            Log.d(TAG, "onClick del surfaceView");
            if (playerVisible) {
                audioPlayer.setVisibility(RelativeLayout.INVISIBLE);
                playerVisible = false;
            } else {
                audioPlayer.setVisibility(RelativeLayout.VISIBLE);
                playerVisible = true;
            }
        }
    });
    playButton.performClick(); // I also tried playAudio(playButton);
}

playAudio（查看 v）

public void playAudio(View v) {
    playButton.setVisibility(View.INVISIBLE);
    pauseButton.setVisibility(View.VISIBLE);
    if (hasPressedPaused == true && hasPressedPlayed == true) {
        Log.d(TAG, "Resume @: " + playbackPosition);
        mediaPlayer.seekTo(playbackPosition);
        mediaPlayer.start();

    } else {
        Log.d(TAG, "playAudio");
        mediaPlayer = new MediaPlayer();

        if (mediaPlayer.isPlaying()) {
            mediaPlayer.reset();
        }

        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setDisplay(surfaceHolder);

        try {
            mediaPlayer.setDataSource(getApplicationContext(), targetUri);
            mediaPlayer.prepare();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        mediaPlayer.start();
        finalTime = mediaPlayer.getDuration();
        startTime = mediaPlayer.getCurrentPosition();
        seekbar.setMax((int) finalTime);
        hasPressedPlayed = true;

        totalTime.setText(String.format(
                "%d:%d",
                TimeUnit.MILLISECONDS.toMinutes((long) finalTime),
                TimeUnit.MILLISECONDS.toSeconds((long) finalTime)
                        - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS
                                .toMinutes((long) finalTime))));
        runningTime.setText(String.format(
                "%d:%d",
                TimeUnit.MILLISECONDS.toMinutes((long) startTime),
                TimeUnit.MILLISECONDS.toSeconds((long) startTime)
                        - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS
                                .toMinutes((long) startTime))));
        seekbar.setProgress((int) startTime);
        myHandler.postDelayed(UpdateSongTime, 100);
    }
    // Set the callback for the audio to finish playing
    mediaPlayer.setOnCompletionListener(new OnCompletionListener() {
        @Override
        public void onCompletion(MediaPlayer arg0) {
            Intent stopPlay = new Intent(context, POIActivity.class);
            startActivity(stopPlay);
        }
    });
}

activity_player.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${packageName}.${activityClass}" >

<SurfaceView
    android:id="@+id/surfaceview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />

<RelativeLayout
    android:id="@+id/audio_player"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:background="#14ad8f" >

    <TextView
        android:id="@+id/audioRunningTime"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/playButton"
        android:text="@string/initial_time"
        android:textAppearance="?android:attr/textAppearanceSmall" />

    <TextView
        android:id="@+id/audioTotalTime"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/playButton"
        android:text="@string/initial_time"
        android:textAppearance="?android:attr/textAppearanceSmall" />

    <SeekBar
        android:id="@+id/seekBarPlayer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/playButton"
        android:layout_toLeftOf="@+id/audioTotalTime"
        android:layout_toRightOf="@+id/audioRunningTime" />

    <Button
        android:id="@+id/moreVolumeButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/seekBarPlayer"
        android:layout_alignRight="@+id/seekBarPlayer"
        android:onClick="adjustVolume"
        android:text="+" />

    <ImageView
        android:id="@+id/stopButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/seekBarPlayer"
        android:layout_marginRight="42dp"
        android:layout_toLeftOf="@+id/moreVolumeButton"
        android:onClick="stopAudio"
        android:src="@drawable/stop_button"
        android:text="STOP" />

    <Button
        android:id="@+id/pauseButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginRight="36dp"
        android:layout_toLeftOf="@+id/stopButton"
        android:onClick="pauseAudio"
        android:text="PAUSE"
        android:visibility="invisible" />

    <Button
        android:id="@+id/playButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginRight="36dp"
        android:layout_toLeftOf="@+id/stopButton"
        android:onClick="playAudio"
        android:text="PLAY" />

    <Button
        android:id="@+id/lessVolumeButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/seekBarPlayer"
        android:layout_alignLeft="@+id/seekBarPlayer"
        android:onClick="adjustVolume"
        android:text="-" />
</RelativeLayout>
</RelativeLayout>

有人知道这里可能出了什么问题吗？有什么解决方法吗？

我的应用需要在 Android 2.3.5 上运行。

Answer 1

似乎需要一些时间才能开始正常播放。在我的onCreate 中，我添加了以下内容：

    playButton.postDelayed(new Runnable() {

        @Override
        public void run() {
            playButton.performClick();
        }
    }, 30);

有趣的是，我的第一次尝试使用 playButton.post(new Runnable(){... 不起作用，如果您将 postDelayed 的第二个参数设置为一个太小的值，它将无法正常工作。