检测用户是否已绘制整个屏幕

Question

我让用户在我的应用程序中进行绘画。应用程序将在整个屏幕绘制后在屏幕上显示一些选项。我想检查用户是否画了整个屏幕。

有没有办法检测用户是否画了整个屏幕？就像在整个屏幕被绘制后触发的事件一样。

以下是我的绘画代码：

    public class DrawingView extends View {
    public int width;
    public int height;
    private Bitmap mBitmap;
    private Canvas mCanvas;
    private Path mPath;
    private Paint mBitmapPaint;
    Context context;
    private Paint circlePaint;
    private Path circlePath;
    Stack mXStack;
    Stack mYStack;

    public DrawingView(Context c) {
        super(c);
        context = c;
        mPath = new Path();
        mXStack = new Stack();
        mYStack = new Stack();
        mBitmapPaint = new Paint(Paint.DITHER_FLAG);
        circlePaint = new Paint();
        circlePath = new Path();
        circlePaint.setAntiAlias(true);
        circlePaint.setColor(Color.BLUE);
        circlePaint.setStyle(Paint.Style.STROKE);
        circlePaint.setStrokeJoin(Paint.Join.MITER);
        circlePaint.setStrokeWidth(50f);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        mCanvas = new Canvas(mBitmap);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
        canvas.drawPath(mPath, mPaint);
        canvas.drawPath(circlePath, circlePaint);
    }

    private float mX, mY;
    private static final float TOUCH_TOLERANCE = 4;

    private void touch_start(float x, float y) {
        mPath.reset();
        mPath.moveTo(x, y);
        mX = x;
        mY = y;
    }

    private void touch_move(float x, float y) {
        float dx = Math.abs(x - mX);
        float dy = Math.abs(y - mY);
        if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
            mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
            mX = x;
            mY = y;

            circlePath.reset();
            circlePath.addCircle(mX, mY, 30, Path.Direction.CW);
        }
    }

    private void touch_up() {
        mPath.lineTo(mX, mY);
        circlePath.reset();
        // commit the path to our offscreen
        mCanvas.drawPath(mPath, mPaint);
        // kill this so we don't double draw
        mPath.reset();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    touch_start(x, y);
                    invalidate();
                    break;
                case MotionEvent.ACTION_MOVE:
                    touch_move(x, y);
                    invalidate();
                    break;
                case MotionEvent.ACTION_UP:
                    touch_up();
                    invalidate();
                    break;
            }
        return true;
        }
}