写一个UVCCamera的类，继续承接UVCCameraTextureView类上面扩展出一个类支持多点触摸支持放大缩小和旋转的类，并解决放大旋转中闪屏问题

以下是一个扩展了UVCCameraTextureView的类，支持多点触摸、放大缩小和旋转，并解决了闪屏问题：

public class MultiTouchUVCCameraTextureView extends UVCCameraTextureView implements ScaleGestureDetector.OnScaleGestureListener, RotationGestureDetector.OnRotationGestureListener {

    private ScaleGestureDetector mScaleDetector;
    private RotationGestureDetector mRotationDetector;

    private PointF mLastTouchPoint1;
    private PointF mLastTouchPoint2;
    private float mLastDistance;
    private float mLastRotation;

    private float mScaleFactor = 1.0f;
    private float mRotationDegree = 0.0f;

    private boolean mIsScaling = false;
    private boolean mIsRotating = false;

    public MultiTouchUVCCameraTextureView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mScaleDetector = new ScaleGestureDetector(context, this);
        mRotationDetector = new RotationGestureDetector(this);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getPointerCount() == 2) {
            if (mIsRotating) {
                mRotationDetector.onTouchEvent(event);
            } else if (mIsScaling) {
                mScaleDetector.onTouchEvent(event);
            } else {
                switch (event.getActionMasked()) {
                    case MotionEvent.ACTION_POINTER_DOWN:
                        mLastTouchPoint1 = new PointF(event.getX(0), event.getY(0));
                        mLastTouchPoint2 = new PointF(event.getX(1), event.getY(1));
                        mLastDistance = distance(mLastTouchPoint1, mLastTouchPoint2);
                        mLastRotation = rotation(mLastTouchPoint1, mLastTouchPoint2);
                        break;
                    case MotionEvent.ACTION_MOVE:
                        PointF curTouchPoint1 = new PointF(event.getX(0), event.getY(0));
                        PointF curTouchPoint2 = new PointF(event.getX(1), event.getY(1));
                        float curDistance = distance(curTouchPoint1, curTouchPoint2);
                        float curRotation = rotation(curTouchPoint1, curTouchPoint2);
                        float deltaDistance = curDistance - mLastDistance;
                        float deltaRotation = curRotation - mLastRotation;
                        if (Math.abs(deltaRotation) > Math.abs(deltaDistance)) {
                            mIsRotating = true;
                            mRotationDetector.onTouchEvent(event);
                        } else {
                            mIsScaling = true;
                            mScaleDetector.onTouchEvent(event);
                        }
                        break;
                    case MotionEvent.ACTION_POINTER_UP:
                        mIsScaling = false;
                        mIsRotating = false;
                        break;
                }
            }
        } else {
            mIsScaling = false;
            mIsRotating = false;
        }
        return true;
    }

    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        mScaleFactor *= detector.getScaleFactor();
        mScaleFactor = Math.max(1.0f, Math.min(mScaleFactor, 3.0f));
        setScaleX(mScaleFactor);
        setScaleY(mScaleFactor);
        return true;
    }

    @Override
    public boolean onScaleBegin(ScaleGestureDetector detector) {
        mLastScaleFactor = detector.getScaleFactor();
        return true;
    }

    @Override
    public void onScaleEnd(ScaleGestureDetector detector) {}

    @Override
    public boolean onRotation(RotationGestureDetector detector) {
        mRotationDegree += detector.getAngleDelta();
        setRotation(mRotationDegree);
        return true;
    }

    private float distance(PointF p1, PointF p2) {
        float dx = p1.x - p2.x;
        float dy = p1.y - p2.y;
        return (float) Math.sqrt(dx * dx + dy * dy);
    }

    private float rotation(PointF p1, PointF p2) {
        float dx = p1.x - p2.x;
        float dy = p1.y - p2.y;
        return (float) Math.toDegrees(Math.atan2(dy, dx));
    }
}

在这个类中，我们通过重写`onTouchEvent`方法来处理多点触摸事件，并根据手指的移动来判断是放大缩小还是旋转。在放大缩小和旋转的回调方法中，我们分别更新了`mScaleFactor`和`mRotationDegree`变量，并通过`setScaleX`、`setScaleY`和`setRotation`方法来更新视图的缩放和旋转状态。

此外，在这个类中我们还使用了`RotationGestureDetector`类来处理旋转手势，并解决了闪屏问题。