写一个UVCCamera的类，继承UVCCameraTextureView类上面扩展出一个类它支持多点触摸支持放大缩小和旋转的类，并解决闪屏问题

好的，以下是一个继承自UVCCameraTextureView并支持多点触摸、放大缩小和旋转的类：

public class MultiTouchUVCCameraTextureView extends UVCCameraTextureView {
    private static final int INVALID_POINTER_ID = -1;

    private float mLastTouchX;
    private float mLastTouchY;
    private int mActivePointerId = INVALID_POINTER_ID;

    private ScaleGestureDetector mScaleDetector;
    private float mScaleFactor = 1.f;

    private RotateGestureDetector mRotateDetector;
    private float mRotationDegrees = 0.f;

    public MultiTouchUVCCameraTextureView(Context context, AttributeSet attrs) {
        super(context, attrs);

        mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
        mRotateDetector = new RotateGestureDetector(context, new RotateListener());
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        // Let the ScaleGestureDetector and RotateGestureDetector inspect all events.
        mScaleDetector.onTouchEvent(ev);
        mRotateDetector.onTouchEvent(ev);

        final int action = ev.getActionMasked();

        switch (action) {
            case MotionEvent.ACTION_DOWN: {
                final float x = ev.getX();
                final float y = ev.getY();

                // Remember where we started (for dragging)
                mLastTouchX = x;
                mLastTouchY = y;

                // Save the ID of this pointer (for dragging)
                mActivePointerId = ev.getPointerId(0);
                break;
            }

            case MotionEvent.ACTION_MOVE: {
                // Find the index of the active pointer and fetch its position
                final int pointerIndex = ev.findPointerIndex(mActivePointerId);
                final float x = ev.getX(pointerIndex);
                final float y = ev.getY(pointerIndex);

                // Calculate the distance moved
                final float dx = x - mLastTouchX;
                final float dy = y - mLastTouchY;

                // Move the camera
                moveCamera(dx, dy);

                // Remember this touch position for the next move event
                mLastTouchX = x;
                mLastTouchY = y;

                break;
            }

            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL: {
                mActivePointerId = INVALID_POINTER_ID;
                break;
            }

            case MotionEvent.ACTION_POINTER_UP: {
                // Extract the index of the pointer that left the screen
                final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
                final int pointerId = ev.getPointerId(pointerIndex);
                if (pointerId == mActivePointerId) {
                    // This was our active pointer going up. Choose a new
                    // active pointer and adjust accordingly.
                    final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
                    mLastTouchX = ev.getX(newPointerIndex);
                    mLastTouchY = ev.getY(newPointerIndex);
                    mActivePointerId = ev.getPointerId(newPointerIndex);
                }
                break;
            }
        }

        return true;
    }

    private void moveCamera(float dx, float dy) {
        // Move the camera based on the distance moved by touch
        Matrix transform = new Matrix();
        transform.postTranslate(dx, dy);
        setTransform(transform);
    }

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            mScaleFactor *= detector.getScaleFactor();

            // Don't let the camera get too small or too large
            mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f));

            // Scale the camera
            Matrix transform = new Matrix();
            transform.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
            setTransform(transform);

            return true;
        }
    }

    private class RotateListener extends RotateGestureDetector.SimpleOnRotateGestureListener {
        @Override
        public boolean onRotate(RotateGestureDetector detector) {
            mRotationDegrees -= detector.getRotationDegreesDelta();

            // Rotate the camera
            Matrix transform = new Matrix();
            transform.postRotate(-mRotationDegrees, detector.getFocusX(), detector.getFocusY());
            setTransform(transform);

            return true;
        }
    }
}

关于闪屏问题，可能是由于相机采集的帧率过低导致的。你可以尝试增加帧率来解决该问题。例如：

mUVCCamera.setPreviewSize(640, 480, 30);

其中，第三个参数表示帧率。你可以适当调整该参数来解决闪屏问题。