捏缩放视频

Question

我想对视频进行缩放缩放，我现在放大视频，但效果不正确，它不是在手指触摸的地方缩放视频，而是在视频的左下角，如何要解决这个问题？

现在看起来如何：https://www.youtube.com/watch?v=VufMUJaV2Nk

MainActivity代码：

public class MainActivity extends Activity {
    // minimum video view width
    static final int MIN_WIDTH = 100;
    // Root view's LayoutParams
    private FrameLayout.LayoutParams mRootParam;
    // Custom Video View
    private VodView mVodView;
    // detector to pinch zoom in/out
    private ScaleGestureDetector mScaleGestureDetector;
    // detector to single tab
    private GestureDetector mGestureDetector;

    private String vidAddress= "rtsp://mpv.cdn3.bigCDN.com:554/bigCDN/definst/mp4:bigbuckbunnyiphone_400.mp4";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRootParam = (LayoutParams) ((View) findViewById(R.id.root_view)).getLayoutParams();
        mVodView = (VodView) findViewById(R.id.vodView1);
        // Video Uri
        Uri vidUri = Uri.parse(vidAddress);
        mVodView.setVideoURI(vidUri);
        // set up gesture listeners
        mScaleGestureDetector = new ScaleGestureDetector(this, new MyScaleGestureListener());
        mGestureDetector = new GestureDetector(this, new MySimpleOnGestureListener());
        mVodView.setOnTouchListener(new OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                mGestureDetector.onTouchEvent(event);
                mScaleGestureDetector.onTouchEvent(event);
                return true;
            }
        });
    }

    @Override
    protected void onResume() {
        mVodView.start();
        super.onResume();
    }

    @Override
    protected void onPause() {
        mVodView.pause();
        super.onPause();
    }

    private class MySimpleOnGestureListener extends SimpleOnGestureListener {

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e) {
            if (mVodView == null)
                return false;
            if (mVodView.isPlaying())
                mVodView.pause();
            else
                mVodView.start();
            return true;
        }

    }

    private class MyScaleGestureListener implements OnScaleGestureListener {
        private int mW, mH;

        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            // scale our video view
            mW *= detector.getScaleFactor();
            mH *= detector.getScaleFactor();
            if (mW < MIN_WIDTH) { // limits width
                mW = mVodView.getWidth();
                mH = mVodView.getHeight();
            }
            Log.d("onScale", "scale=" + detector.getScaleFactor() + ", w=" + mW + ", h=" + mH);
            mVodView.setFixedVideoSize(mW, mH); // important
            mRootParam.width = mW;
            mRootParam.height = mH;
            return true;
        }

        @Override
        public boolean onScaleBegin(ScaleGestureDetector detector) {
            mW = mVodView.getWidth();
            mH = mVodView.getHeight();
            Log.d("onScaleBegin", "scale=" + detector.getScaleFactor() + ", w=" + mW + ", h=" + mH);
            return true;
        }

        @Override
        public void onScaleEnd(ScaleGestureDetector detector) {
            Log.d("onScaleEnd", "scale=" + detector.getScaleFactor() + ", w=" + mW + ", h=" + mH);
        }
    }
}

自定义视图：

public class VodView extends VideoView {

    public VodView(Context context) {
        super(context);
    }

    public VodView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public VodView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }


    /**
     * Resize video view by using SurfaceHolder.setFixedSize(...). See {@link android.view.SurfaceHolder#setFixedSize}
     * @param width
     * @param height
     */
    public void setFixedVideoSize(int width, int height)
    {
        getHolder().setFixedSize(width, height);
    }
}

的xml：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.attracti.scalevideo.MainActivity" >

    <com.example.attracti.scalevideo.VodView
        android:id="@+id/vodView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

</FrameLayout>