android - getDuration 正在抛出尝试调用无效的媒体播放器第二次调用媒体播放器时？

Question

下面是我正在使用的代码。我正在使用一个 vimeo 视频 url，它在我第一次加载 Activity 时工作正常，但在第二次调用 Activity 时出现问题，它显示消息尝试在无效的媒体播放器上调用 getDuration。

public class VideoActivity extends Activity {

    public LinearLayout main_Lay;
    private TextView textViewPlayed;
    private TextView textViewLength;
    private SeekBar seekBarProgress;
    private SurfaceView surfaceViewFrame;
    private ImageView imageViewPauseIndicator;
    private MediaPlayer player;
    private SurfaceHolder holder;
    private ProgressBar progressBarWait;
    private Timer updateTimer;
    // private Bundle extras;
    private Animation hideMediaController;
    private LinearLayout linearLayoutMediaController;
    private static final String TAG = "androidEx2 = VideoSample";
    public boolean isFullScreen = false;
    private Context m_context;
    public GestureDetector ggg;

    @SuppressWarnings("deprecation")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        setContentView(R.layout.video_layout);
        this.m_context = this;

        main_Lay = (LinearLayout) findViewById(R.id.main_lay);
        main_Lay.startAnimation(AnimationUtils.loadAnimation(this,
            R.anim.slide_out_up));
        surfaceViewFrame = (SurfaceView) findViewById(R.id.surfaceViewFrame);
        final Button button = (Button) findViewById(R.id.full);
        ggg = new GestureDetector(new OnGestureListener() {

            public boolean onSingleTapUp(MotionEvent arg0) {
                // TODO Auto-generated method stub
                try {
                    if (player != null) {

                        if (player.isPlaying())
                            player.stop();
                        player.reset();

                        player.release();

                        if (updateTimer != null) {
                            updateTimer.cancel();
                        }
                        finish();
                    }
                } catch (Exception ex) {
                    ex.printStackTrace();
                    player.reset();
                    player.release();

                    if (updateTimer != null) {
                        updateTimer.cancel();
                    }
                    finish();
                }
                return true;
            }

            public void onShowPress(MotionEvent arg0) {
                // TODO Auto-generated method stub

            }

            public boolean onScroll(MotionEvent arg0, MotionEvent arg1,
                float arg2, float arg3) {
                // TODO Auto-generated method stub
                return false;
            }

            public void onLongPress(MotionEvent arg0) {
                // TODO Auto-generated method stub

            }

            @Override
            public boolean onFling(MotionEvent arg0, MotionEvent arg1,
                float arg2, float arg3) {
                // TODO Auto-generated method stub
                return false;
            }

            @Override
            public boolean onDown(MotionEvent arg0) {
                // TODO Auto-generated method stub
                return false;
            }
        });

button.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
                // TODO Auto-generated method stub
        if (player != null) {
            if (!isFullScreen) {
                isFullScreen = true;
                button.setBackgroundResource(R.drawable.fullscreen_exit_alt);

                        // Get the width of the screen
                int screenWidth = ((Activity) m_context)
                .getWindowManager().getDefaultDisplay()
                .getWidth();
                int screenHeight = ((Activity) m_context)
                .getWindowManager().getDefaultDisplay()
                .getHeight();

                WidthResizeAnimation zoom_out = new WidthResizeAnimation(
                    main_Lay, screenWidth, screenHeight, false);
                zoom_out.setDuration(600);
                zoom_out.setFillAfter(true);

                WidthResizeAnimation zoom_outt = new WidthResizeAnimation(
                    surfaceViewFrame, screenWidth, screenHeight,
                    false);
                zoom_outt.setDuration(600);
                zoom_outt.setFillAfter(true);
                surfaceViewFrame.startAnimation(zoom_outt);
                main_Lay.startAnimation(zoom_out);

            } else {
                isFullScreen = false;
                button.setBackgroundResource(R.drawable.fullscreen_alt);
                int videoWidth = player.getVideoWidth();
                int videoHeight = player.getVideoHeight();
                float videoProportion = (float) videoWidth
                / (float) videoHeight;
                Log.i(TAG, "VIDEO SIZES: W: " + videoWidth + " H: "
                    + videoHeight + " PROP: " + videoProportion);

                        // Get the width of the screen
                int screenWidth = ((Activity) m_context)
                .getWindowManager().getDefaultDisplay()
                .getWidth();
                int screenHeight = ((Activity) m_context)
                .getWindowManager().getDefaultDisplay()
                .getHeight();
                float screenProportion = (float) screenWidth
                / (float) screenHeight;
                Log.i(TAG, "VIDEO SIZES: W: " + screenWidth + " H: "
                    + screenHeight + " PROP: " + screenProportion);

                        // Get the SurfaceView layout
                        // parameters
                android.view.ViewGroup.LayoutParams lp = surfaceViewFrame
                .getLayoutParams();
                android.view.ViewGroup.LayoutParams mainLayoutParam = main_Lay
                .getLayoutParams();

                if (videoProportion > screenProportion) {
                    lp.width = screenWidth;
                    lp.height = (int) ((float) screenWidth / videoProportion);

                    lp.width = (lp.width / 100) * 80;
                    lp.height = (lp.height / 100) * 80;

                } else {
                    lp.width = (int) (videoProportion * (float) screenHeight);
                    lp.height = screenHeight;

                    lp.width = (lp.width / 100) * 70;
                    lp.height = (lp.height / 100) * 70;

                }
                WidthResizeAnimation zoom_in = new WidthResizeAnimation(
                    main_Lay, lp.width, lp.height, false);
                zoom_in.setDuration(600);
                zoom_in.setFillAfter(true);
                        // zoom_in.start();

                WidthResizeAnimation zoom_inn = new WidthResizeAnimation(
                    surfaceViewFrame, lp.width, lp.height, false);
                zoom_inn.setDuration(600);
                zoom_inn.setFillAfter(true);
                        // zoom_in.start();
                surfaceViewFrame.startAnimation(zoom_inn);
                main_Lay.startAnimation(zoom_in);

            }
        }
    }
});
final Button pause = (Button) findViewById(R.id.pause);

pause.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
                // TODO Auto-generated method stub
        if (player != null) {
            if (player.isPlaying()) {
                player.pause();
                pause.setBackgroundResource(R.drawable.play);
                imageViewPauseIndicator.setVisibility(View.GONE);
            } else {
                pause.setBackgroundResource(R.drawable.pause);
                player.start();
                imageViewPauseIndicator.setVisibility(View.GONE);
            }
        }
    }
});

linearLayoutMediaController = (LinearLayout) findViewById(R.id.linearLayoutMediaController);
linearLayoutMediaController.setVisibility(View.GONE);

hideMediaController = AnimationUtils.loadAnimation(m_context,
    R.anim.disapearing);
hideMediaController.setAnimationListener(new AnimationListener() {

    @Override
    public void onAnimationStart(Animation arg0) {
                // TODO Auto-generated
                // method stub
        linearLayoutMediaController.setVisibility(View.GONE);
    }

    @Override
    public void onAnimationRepeat(Animation arg0) {
                // TODO Auto-generated
                // method stub

    }

    @Override
    public void onAnimationEnd(Animation arg0) {
                // TODO Auto-generated
                // method stub

    }
});

imageViewPauseIndicator = (ImageView) findViewById(R.id.imageViewPauseIndicator);
imageViewPauseIndicator.setVisibility(View.GONE);
if (player != null) {
    if (!player.isPlaying()) {
        imageViewPauseIndicator.setVisibility(View.GONE);
    }
}

textViewPlayed = (TextView) findViewById(R.id.textViewPlayed);
textViewLength = (TextView) findViewById(R.id.textViewLength);

surfaceViewFrame.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
                // TODO Auto-generated
                // method stub
        if (arg0.getId() == R.id.surfaceViewFrame) {
            if (linearLayoutMediaController.getVisibility() == View.GONE) {
                linearLayoutMediaController.setVisibility(View.VISIBLE);
                hideMediaController();
            }
        }
    }
});
surfaceViewFrame.setClickable(false);

seekBarProgress = (SeekBar) findViewById(R.id.seekBarProgress);
seekBarProgress
.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {

    @Override
    public void onStopTrackingTouch(SeekBar arg0) {
                        // TODO Auto-generated
                        // method stub
        if (player.isPlaying()) {
            progressBarWait.setVisibility(View.VISIBLE);
            player.seekTo(arg0.getProgress() * 1000);
            Log.i(TAG,
                "========== SeekTo : " + arg0.getProgress());
        }
    }

    @Override
    public void onStartTrackingTouch(SeekBar arg0) {
                        // TODO Auto-generated
                        // method stub

    }

    @Override
    public void onProgressChanged(SeekBar seekBar,
        int progress, boolean fromUser) {
        Log.i(TAG, "========== onProgressChanged : " + progress
            + " from user: " + fromUser);
        if (!fromUser) {
            textViewPlayed
            .setText(durationInSecondsToString(progress));
        }
    }
});
seekBarProgress.setProgress(0);

progressBarWait = (ProgressBar) findViewById(R.id.progressBarWait);

holder = surfaceViewFrame.getHolder();
holder.addCallback(new Callback() {

    @Override
    public void surfaceDestroyed(SurfaceHolder arg0) {
                // TODO Auto-generated method stub

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
                // TODO Auto-generated method stub
        player.setDisplay(holder);
        playVideo();
    }

    @Override
    public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2,
        int arg3) {
                // TODO Auto-generated method stub

    }
});
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

player = new MediaPlayer();
player.setOnPreparedListener(new OnPreparedListener() {

    @Override
    public void onPrepared(MediaPlayer arg0) {
                // TODO Auto-generated method stub
        Log.i(TAG, "========== onPrepared ===========");

        try {
                    int duration = player.getDuration() / 1000; // duration
                                                                // in
                                                                // seconds
                    seekBarProgress.setMax(duration);
                    textViewLength.setText(durationInSecondsToString(duration));
                    progressBarWait.setVisibility(View.GONE);

                    // Get the dimensions of the video
                    int videoWidth = player.getVideoWidth();
                    int videoHeight = player.getVideoHeight();
                    float videoProportion = (float) videoWidth
                    / (float) videoHeight;
                    Log.i(TAG, "VIDEO SIZES: W: " + videoWidth + " H: "
                        + videoHeight + " PROP: " + videoProportion);
                    player.setVideoScalingMode(MediaPlayer.VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING);
                    // Get the width of the screen
                    int screenWidth = ((Activity) m_context).getWindowManager()
                    .getDefaultDisplay().getWidth();
                    int screenHeight = ((Activity) m_context)
                    .getWindowManager().getDefaultDisplay().getHeight();
                    float screenProportion = (float) screenWidth
                    / (float) screenHeight;
                    Log.i(TAG, "VIDEO SIZES: W: " + screenWidth + " H: "
                        + screenHeight + " PROP: " + screenProportion);

                    // Get the SurfaceView layout
                    // parameters
                    android.view.ViewGroup.LayoutParams lp = surfaceViewFrame
                    .getLayoutParams();
                    android.view.ViewGroup.LayoutParams mainLayoutParam = main_Lay
                    .getLayoutParams();

                    if (videoProportion > screenProportion) {
                        lp.width = screenWidth;
                        lp.height = (int) ((float) screenWidth / videoProportion);
                        lp.width = (lp.width / 100) * 80;
                        lp.height = (lp.height / 100) * 80;
                    } else {
                        lp.width = (int) (videoProportion * (float) screenHeight);
                        lp.height = screenHeight;

                        lp.width = (lp.width / 100) * 90;
                        lp.height = (lp.height / 100) * 90;
                    }

                    // Commit the layout parameters
                    surfaceViewFrame.setLayoutParams(lp);
                    RelativeLayout.LayoutParams rr = new RelativeLayout.LayoutParams(
                        lp.width, lp.height);
                    rr.addRule(RelativeLayout.CENTER_IN_PARENT);
                    main_Lay.setLayoutParams(rr);

                    // Start video
                    if (!player.isPlaying()) {
                        player.start();
                        updateMediaProgress();
                        linearLayoutMediaController.setVisibility(View.VISIBLE);
                        hideMediaController();
                    }
                    surfaceViewFrame.setClickable(true);
                } catch (Exception ex) {

                    player.release();
                    finish();
                    ex.printStackTrace();
                }
                ;

            }
        });

player.setOnErrorListener(new OnErrorListener() {

    @Override
    public boolean onError(MediaPlayer arg0, int arg1, int arg2) {
                // TODO Auto-generated method stub
        if (arg0.isPlaying()) {
            arg0.stop();
        }
        arg0.release();
        finish();

        Log.e("Lrapp", "Error code" + arg1);
        return true;
    }
});
player.setOnCompletionListener(new OnCompletionListener() {

    @Override
    public void onCompletion(MediaPlayer arg0) {
                // TODO Auto-generated method stub
        arg0.stop();
        arg0.release();
        if (updateTimer != null) {
            updateTimer.cancel();
        }
        finish();
    }
});
player.setOnBufferingUpdateListener(new OnBufferingUpdateListener() {

    @Override
    public void onBufferingUpdate(MediaPlayer arg0, int arg1) {
                // TODO Auto-generated method stub
        int progress = (int) ((float) arg0.getDuration() * ((float) arg1 / (float) 100));
        seekBarProgress.setSecondaryProgress(progress / 1000);

    }
});
player.setOnSeekCompleteListener(new OnSeekCompleteListener() {

    @Override
    public void onSeekComplete(MediaPlayer arg0) {
                // TODO Auto-generated method stub
        progressBarWait.setVisibility(View.GONE);
    }
});
player.setScreenOnWhilePlaying(true);

}

@Override
public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub

    return ggg.onTouchEvent(event);

}

@Override
public void onBackPressed() {
        // TODO Auto-generated method stub
    super.onBackPressed();

    try {
        if (player != null) {

            if (player.isPlaying())
                player.stop();

            player.release();

            if (updateTimer != null) {
                updateTimer.cancel();
            }
            finish();
        }
    } catch (Exception ex) {
        ex.printStackTrace();
        player.release();

        if (updateTimer != null) {
            updateTimer.cancel();
        }
        finish();
    }
}

private void playVideo() {

    new Thread(new Runnable() {
        public void run() {
            try {
                player.setDataSource("video url");
                player.prepareAsync();
            } catch (IllegalArgumentException e) {
                showToast("Error while playing video. Please, check your network connection.");
                Log.i(TAG,
                    "========== IllegalArgumentException ===========");
                e.printStackTrace();
                if (player.isPlaying())
                    player.stop();
                player.release();
                player = null;
                if (updateTimer != null) {
                    updateTimer.cancel();
                }
                finish();
            } catch (IllegalStateException e) {
                showToast("Error while playing video. Please, check your network connection.");
                Log.i(TAG, "========== IllegalStateException ===========");
                e.printStackTrace();
                if (player.isPlaying())
                    player.stop();
                player.release();
                player = null;
                if (updateTimer != null) {
                    updateTimer.cancel();
                }
                finish();
            } catch (IOException e) {
                showToast("Error while playing video. Please, check your network connection.");
                Log.i(TAG, "========== IOException ===========");
                e.printStackTrace();
                if (player.isPlaying())
                    player.stop();
                player.release();
                player = null;
                if (updateTimer != null) {
                    updateTimer.cancel();
                }
                finish();
            }
        }
    }).start();

}

private void showToast(final String string) {
    ((Activity) m_context).runOnUiThread(new Runnable() {
        public void run() {
            Toast.makeText(m_context, string, Toast.LENGTH_LONG).show();
            ;
        }
    });
}

private void hideMediaController() {
    new Thread(new Runnable() {
        public void run() {
            try {
                Thread.sleep(5000);
                ((Activity) m_context).runOnUiThread(new Runnable() {
                    public void run() {
                        linearLayoutMediaController
                        .startAnimation(hideMediaController);
                    }
                });
            } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }).start();
}

private void updateMediaProgress() {
    updateTimer = new Timer("progress Updater");
    updateTimer.scheduleAtFixedRate(new TimerTask() {
        @Override
        public void run() {
            ((Activity) m_context).runOnUiThread(new Runnable() {
                public void run() {

                    try {

                        seekBarProgress.setProgress(player
                            .getCurrentPosition() / 1000);
                    } catch (Exception ex) {
                        ex.printStackTrace();
                        player.release();
                    }
                }
            });
        }
    }, 0, 1000);
}

public static String durationInSecondsToString(int sec) {
    int hours = sec / 3600;
    int minutes = (sec / 60) - (hours * 60);
    int seconds = sec - (hours * 3600) - (minutes * 60);
    String formatted = String.format("%d:%02d:%02d", hours, minutes,
        seconds);
    return formatted;
}

}

Answer 1

第二次打开 Activity 后，表面回调被调用 -> playVideo() -> 播放器未正确初始化。解决方案可能是:
将其插入到 playVideo() 方法中:

if (player != null)
{
    player.reset();
} else 
{
    player = new MediaPlayer();
}
//init