我有一个我无法解决的问题。我正在使用 MediaPlayer 类来播放视频；但是，我总是失去原来的纵横比。这里提到了媒体播放器代码和xml代码。我已经尝试了很多东西，但仍然无法解决问题。我需要保持原来的纵横比。我已在我的 Android list 文件中声明此 Activity 为全屏。我还在媒体播放器代码之后附上了 xml 代码。请多多指教。

private class ErrorListener implements OnErrorListener {
    // FIXME: @Override
    public boolean onError(MediaPlayer mp, int what, int extra) {
        String message = "Unknown error";
        switch (what) {
        case MediaPlayer.MEDIA_ERROR_UNKNOWN:
            message = "Unable to play media";
            showError(message);
            break;
        case MediaPlayer.MEDIA_ERROR_SERVER_DIED:
            message = "Server failed";
            showError(message);
            break;
        case MediaPlayer.MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK:
            message = "Invalid media";
            showError(message);
            break;
        }
        return false;
    }
}

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    setContentView(R.layout.videoview);
    Intent intent = getIntent();
    uri = intent.getData();
    new loadMovie().execute();
    mPreview = (SurfaceView) findViewById(R.id.videoview);
    mPreview.bringToFront();
    holder = mPreview.getHolder();
    holder.addCallback(this);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    mediaPlayer = new MediaPlayer();

}// onCreate Method Ends

private void playVideo() {
    doCleanUp();
    try {
        mediaPlayer.setDataSource(this, uri);
    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    } catch (SecurityException e) {
        e.printStackTrace();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    mediaPlayer.setDisplay(holder);
    try {
        mediaPlayer.prepare();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    mediaPlayer.setOnErrorListener(new ErrorListener());
    mediaPlayer.setOnBufferingUpdateListener(this);
    mediaPlayer.setOnCompletionListener(this);
    mediaPlayer.setOnPreparedListener(this);
    mediaPlayer.setOnVideoSizeChangedListener(this);
    mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
    mediaController = new MediaController(this);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    mediaController.show();
    return false;
}

// --MediaPlayerControl
// methods----------------------------------------------------
public void start() {
    mediaPlayer.start();
}

public void pause() {
    mediaPlayer.pause();
}

public int getDuration() {
    return mediaPlayer.getDuration();
}

public int getCurrentPosition() {
    return mediaPlayer.getCurrentPosition();
}

public void seekTo(int i) {
    mediaPlayer.seekTo(i);
}

public boolean isPlaying() {
    return mediaPlayer.isPlaying();
}

public int getBufferPercentage() {
    return 0;
}

public boolean canPause() {
    return true;
}

public boolean canSeekBackward() {
    return true;
}

public boolean canSeekForward() {
    return true;
}

// End of MediaPlayer
// Controls--------------------------------------------------------
// ------------------------

public void onPrepared(MediaPlayer mediaPlayer) {
    mediaController.setMediaPlayer(this);
    mediaController.setAnchorView(findViewById(R.id.videoview));
    mIsVideoReadyToBePlayed = true;

    if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
        startVideoPlayback();
    }

    handler.post(new Runnable() {
        public void run() {
            mediaController.setEnabled(true);
            mediaController.show();
        }
    });
}

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

}

public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    playVideo();
}

public void surfaceDestroyed(SurfaceHolder arg0) {

}

private void startVideoPlayback() {
    holder.setFixedSize(mVideoWidth, mVideoHeight);
    mediaPlayer.start();
}

public void onVideoSizeChanged(MediaPlayer mp, int width, int height) {
    if (width == 0 || height == 0) {
        return;
    }
    mIsVideoSizeKnown = true;
    mVideoWidth = width;
    mVideoHeight = height;
    if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
        startVideoPlayback();
    }

}

public void onCompletion(MediaPlayer arg0) {

}

public void onBufferingUpdate(MediaPlayer mp, int percent) {

}

private void releaseMediaPlayer() {
    mediaPlayer.release();
    mediaPlayer = null;
}

private void doCleanUp() {
    mVideoWidth = 0;
    mVideoHeight = 0;
    mIsVideoReadyToBePlayed = false;
    mIsVideoSizeKnown = false;
}

这是 XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
>
<SurfaceView android:id="@+id/videoview"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    />
 </LinearLayout>

谁能告诉我如何保持视频的纵横比？

最佳答案

首先使用 Gravity.CENTER 创建一个 Relative Layout，并将 Surface View 附加到其中。这将确保视频在屏幕内居中。

此外，如果您正在使用 Activity ，请使用“黑色”主题以避免渐变

在您的 SurfaceView 中，创建一个监听器:

mMediaPlayer = new MediaPlayer();

...

MediaPlayer.OnVideoSizeChangedListener mOnVideoSizeChangedListener = new MediaPlayer.OnVideoSizeChangedListener() {

    @Override
    public void onVideoSizeChanged(MediaPlayer mp, int width, int height) {

         setFitToFillAspectRatio(mp, width, height);

    }
};
mMediaPlayer.setOnVideoSizeChangedListener(mOnVideoSizeChangedListener);

...

最后是 SurfaceView 中的 fit to fill 方法。这将适用于横向和纵向

private void setFitToFillAspectRatio(MediaPlayer mp, int videoWidth, int videoHeight)
{
    if(mp != null)
    {       
        Integer screenWidth = ((Activity) mContext).getWindowManager().getDefaultDisplay().getWidth();
        Integer screenHeight = ((Activity) mContext).getWindowManager().getDefaultDisplay().getHeight();
        android.view.ViewGroup.LayoutParams videoParams = getLayoutParams();


        if (videoWidth > videoHeight)
        {
            videoParams.width = screenWidth;
            videoParams.height = screenWidth * videoHeight / videoWidth;
        }
        else
        {
            videoParams.width = screenHeight * videoWidth / videoHeight;
            videoParams.height = screenHeight;
        }


        setLayoutParams(videoParams);
    }
}

关于Android:MediaPlayer 视频纵横比问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8240051/