Question

我正在尝试在SD卡上保存画布。基本上我在onDraw（Canvas画布）方法中绘制两个位图（一个在另一个上面）。但是当我保存文件时，只存储底层的位图。我在这里发布了onDraw方法的代码：

    Paint paint = new Paint();
    paint.setColor(Color.BLACK);

    //rectangle for the first image
    rct = new Rect(10, 10, canvas.getWidth(), canvas.getHeight());

    // rectangle for the second image, the secong image is drawn where the user touches the screen
    new_image = new RectF(touchX, touchY, touchX + secondBitmap.getWidth(),
                touchY + secondBitmap.getHeight());

   //this is the bitmap that is drawn first
    canvas.drawBitmap(firstBitmap, null, rct, paint);

    //this is the bitmap drawn on top of the first bitmap on user touch
    canvas.drawBitmap(secondBitmap, null, new_image, paint);

    canvas.save();

在MainActivity上写的SD卡上保存画布的代码是：

   Bitmap bm = canvas.getDrawingCache() // canvas in an object of the class I extended from View
   String path = Environment.getExternalStorageDirectory()
            .getAbsolutePath();
   boolean exists = (new File(path)).exists();

   OutputStream outStream = null;
   File file = new File(path, "drawn_image" + ".jpg");

   try {
      outStream = new FileOutputStream(file);
      bmp.compress(Bitmap.CompressFormat.JPEG, 100, outStream);
      outStream.flush();
      outStream.close();
      } 
   catch (FileNotFoundException e) {
    e.printStackTrace();
    } 
   catch (IOException e) {
        e.printStackTrace();
    }

问题是只有基本图像（onDraw（）方法的firstBitmap）保存在SDCard而不是整个画布上（同时包含两个图像）。我是画布的新手...所以任何帮助都会非常感激

Answer 1

当调用getDrawingcache（）时，它会使视图无效以获取完整缓存。所以调试你的代码并检查它是否在视图中遍历onDraw（）方法的每一行。

无法使用重叠的位图图像提取绘图缓存

1 个答案: