Question

我正在使用画布绘图，它运行良好但图像现在保存在SD卡中，我保存的代码是

     mBitmap = Bitmap.createBitmap(mContent.getWidth(), mContent.getHeight(), Bitmap.Config.RGB_565);
        Canvas canvas = new Canvas(mBitmap);
        try {
            FileCache fileCache = new FileCache(SignatureActivity.this);
            FileOutputStream mFileOutStream = new FileOutputStream(fileCache.getFile(imageURL));

            v.draw(canvas);
            mBitmap.compress(Bitmap.CompressFormat.PNG, 90, mFileOutStream);
            mFileOutStream.flush();
            mFileOutStream.close();
            String url = Images.Media.insertImage(getContentResolver(), mBitmap, "title", null);
            signimage.setImageBitmap(mBitmap);
            System.err.println("" + url);
            return url;

        } catch (Exception e) {
            Log.v("log_tag", e.toString());
        }

Answer 1

使用此代码

        @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawPath(path, paint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float eventX = event.getX();
        float eventY = event.getY();

        isSignedEnable = true;
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                path.moveTo(eventX, eventY);
                lastTouchX = eventX;
                lastTouchY = eventY;
                return true;

            case MotionEvent.ACTION_MOVE:

            case MotionEvent.ACTION_UP:

                resetDirtyRect(eventX, eventY);
                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);
                }
                path.lineTo(eventX, eventY);
                break;

            default:
                debug("Ignored touch event: " + event.toString());
                return false;
        }

        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;
    }

    private void debug(String string) {
    }

    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;
        }
    }

    private void resetDirtyRect(float eventX, float eventY) {
        dirtyRect.left = Math.min(lastTouchX, eventX);
        dirtyRect.right = Math.max(lastTouchX, eventX);
        dirtyRect.top = Math.min(lastTouchY, eventY);
        dirtyRect.bottom = Math.max(lastTouchY, eventY);
    }
}

然后保存图片

 v.draw(canvas);
            mBitmap.compress(Bitmap.CompressFormat.PNG, 90, mFileOutStream);
            mFileOutStream.flush();
            mFileOutStream.close();
            String url = Images.Media.insertImage(getContentResolver(), mBitmap, "title", null);
            signimage.setImageBitmap(mBitmap);
            System.err.println("" + url);

Answer 2

您检查位图是否为空。如果为null则创建位图

            if (mBitmap == null) {
            mBitmap = Bitmap.createBitmap(mContent.getWidth(), mContent.getHeight(), Bitmap.Config.RGB_565);
        }

        Canvas canvas = new Canvas(mBitmap);
        try {
            FileCache fileCache = new FileCache(SignatureActivity.this);
            FileOutputStream mFileOutStream = new FileOutputStream(fileCache.getFile(imageURL));

            v.draw(canvas);
            mBitmap.compress(Bitmap.CompressFormat.PNG, 90, mFileOutStream);
            mFileOutStream.flush();
            mFileOutStream.close();
            String url = Images.Media.insertImage(getContentResolver(), mBitmap, "title", null);
            signimage.setImageBitmap(mBitmap);
            System.err.println("" + url);
            return url;

        } catch (Exception e) {
            Log.v("log_tag", e.toString());
        }
        return "";

图像未保存在Canvas的SD卡中

2 个答案: