android 签字版

public class DrawLineLayout extends View {    private static final float STROKE_WIDTH = 5f;    /** Need to track this so the dirty region can accommodate the stroke. **/    private static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;    private Paint paint = new Paint();    private Path path = new Path();    /**     * Optimizes painting by invalidating the smallest possible area.     */    private float lastTouchX;    private float lastTouchY;     private final RectF dirtyRect = new RectF();    private Bitmap cachebBitmap;    public DrawLineLayout(Context context, AttributeSet attrs) {        super(context, attrs);        paint.setAntiAlias(true);        paint.setColor(Color.BLACK);        paint.setStyle(Paint.Style.STROKE);        paint.setStrokeJoin(Paint.Join.ROUND);        paint.setStrokeWidth(STROKE_WIDTH);    }    /**     * 用于清空你已经绘制好的图     */    public void clear() {        path.reset();        // Repaints the entire view.        invalidate();//重新调用绘制    }    @Override    protected void onDraw(Canvas canvas) {        canvas.drawPath(path, paint);    }//更加触摸点绘制线    @Override    public boolean onTouchEvent(MotionEvent event) {        float eventX = event.getX();        float eventY = event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                path.moveTo(eventX, eventY);                lastTouchX = eventX;                lastTouchY = eventY;                // There is no end point yet, so don't waste cycles invalidating.                return true;            case MotionEvent.ACTION_MOVE:            case MotionEvent.ACTION_UP:                // Start tracking the dirty region.                resetDirtyRect(eventX, eventY);                // When the hardware tracks events faster than they are delivered, the                // event will contain a history of those skipped points.                int historySize = event.getHistorySize();                for (int i = 0; i < historySize; i++) {                    float historicalX = event.getHistoricalX(i);                    float historicalY = event.getHistoricalY(i);                    expandDirtyRect(historicalX, historicalY);                    path.lineTo(historicalX, historicalY);                }                // After replaying history, connect the line to the touch point.                path.lineTo(eventX, eventY);                break;            default:                return false;        }        // Include half the stroke width to avoid clipping.        invalidate(                (int) (dirtyRect.left - HALF_STROKE_WIDTH),                (int) (dirtyRect.top - HALF_STROKE_WIDTH),                (int) (dirtyRect.right + HALF_STROKE_WIDTH),                (int) (dirtyRect.bottom + HALF_STROKE_WIDTH));        lastTouchX = eventX;        lastTouchY = eventY;        return true;    }    /**     * Called when replaying history to ensure the dirty region includes all     * points.     */    private void expandDirtyRect(float historicalX, float historicalY) {        if (historicalX < dirtyRect.left) {            dirtyRect.left = historicalX;        } else if (historicalX > dirtyRect.right) {            dirtyRect.right = historicalX;        }        if (historicalY < dirtyRect.top) {            dirtyRect.top = historicalY;        } else if (historicalY > dirtyRect.bottom) {            dirtyRect.bottom = historicalY;        }    }    /**     * Resets the dirty region when the motion event occurs.     */    private void resetDirtyRect(float eventX, float eventY) {        // The lastTouchX and lastTouchY were set when the ACTION_DOWN        // motion event occurred.        dirtyRect.left = Math.min(lastTouchX, eventX);        dirtyRect.right = Math.max(lastTouchX, eventX);        dirtyRect.top = Math.min(lastTouchY, eventY);        dirtyRect.bottom = Math.max(lastTouchY, eventY);    }    /**     * 保存view视图的bitmap信息     * @return bitmap数据     */    public Bitmap getImage() {        Bitmap bitmap = Bitmap.createBitmap(1920, 1080, Bitmap.Config.RGB_565);        Canvas canvas = new Canvas(bitmap);        /**         * 绘制背景         */        Drawable bgDrawable = getBackground();        if (bgDrawable != null)            bgDrawable.draw(canvas);        else            canvas.drawColor(Color.WHITE);        draw(canvas);// 绘制view视图的内容        return bitmap;    }    /**     * 将图像保存到文件     * @return 返回false表示保存失败     */    public boolean saveImageToFile(String filePath) {        try {            File file = new File(filePath);            if (!file.exists()) {                file.createNewFile();            }            FileOutputStream fos = new FileOutputStream(file);            getImage().compress(Bitmap.CompressFormat.PNG, 100, fos);            fos.flush();            fos.close();//            Toast.makeText(getContext(),"wanc",Toast.LENGTH_SHORT).show();            return true;        } catch (FileNotFoundException e) {            return false;        } catch (IOException e) {            return false;        }    }}