public class BAGraffitiView extends View {    private int panitColor;    private Bitmap mBitmap;    private float downX, downY;    private float tempX, tempY;    private Bitmap src;    private List
    
      drawPathList;    private Paint paint;    private Path path;    private Bitmap resultBitmap;    public BAGraffitiView(Context context) {        super(context);    }    public BAGraffitiView(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);        init();    }    public BAGraffitiView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    private void init() {        drawPathList = new ArrayList<>();    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        if (mBitmap != null) {            if (src == null) {                int width = canvas.getWidth();                int height = canvas.getHeight();                int bWidth = mBitmap.getWidth();                int bHeight = mBitmap.getHeight();                float wScale = (float) width/bWidth;                float hScale = (float) height/bHeight;                Matrix matrix = new Matrix();                matrix.postScale(wScale, hScale);                src = Bitmap.createBitmap(mBitmap, 0, 0, bWidth, bHeight, matrix, true);            }            canvas.drawBitmap(src, 0, 0, null);        }        if (drawPathList != null && drawPathList.size() != 0) {            for (DrawPath drawPath : drawPathList) {                canvas.drawPath(drawPath.path, drawPath.paint);            }        }        canvas.save();    }    private void initValue() {        paint = new Paint();        path = new Path();        paint.setAntiAlias(true);        paint.setStrokeWidth(10);        paint.setStyle(Paint.Style.STROKE);        if (panitColor == 0) {            paint.setColor(Color.RED);        } else {            paint.setColor(panitColor);        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                initValue();                downX = event.getX();                downY = event.getY();                path.moveTo(downX, downY);                invalidate();                tempX = downX;                tempY = downY;                DrawPath drawPath = new DrawPath();                drawPath.paint = paint;                drawPath.path = path;                drawPathList.add(drawPath);                break;            case MotionEvent.ACTION_MOVE:                float moveX = event.getX();                float moveY = event.getY();                path.quadTo(tempX, tempY, moveX, moveY);                invalidate();                tempX = moveX;                tempY = moveY;                break;        }        return true;    }    //设置颜色    public void setPanitColor(int panitColor) {        this.panitColor = panitColor;    }    //设置背景图片    public void setmBitmap(Bitmap mBitmap) {        this.mBitmap = mBitmap;    }    //撤销    public void undo() {        if (drawPathList.size() > 0) {            drawPathList.remove(drawPathList.size() - 1);            invalidate();        }    }    public Bitmap getSrc() {        return this.src;    }    class DrawPath {        Paint paint;        Path path;    }}