Android 无法使用叠加的位图图像提取图形缓存
我试图在SD卡上保存画布。基本上，我用onDraw（Canvas Canvas）方法绘制了两个位图（一个在另一个上面）。但是当我保存文件时，只存储底层位图。我在这里发布onDraw方法的代码：Android 无法使用叠加的位图图像提取图形缓存,android,bitmap,android-canvas,Android,Bitmap,Android Canvas,我试图在SD卡上保存画布。基本上，我用onDraw（Canvas Canvas）方法绘制了两个位图（一个在另一个上面）。但是当我保存文件时，只存储底层位图。我在这里发布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
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();
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();
}