从ImageViews保存三个可绘制的位图

Question

我有三个图像视图，我正在尝试使用以下代码将每个位图保存到文件中。

private WriteImage writeimage

writeImage = new WriteImage();
writeImage.WriteImageToDisk(((BitmapDrawable)img_view_left.getDrawable()).getBitmap(),ex.get(0).getLeftPhoto());
writeImage.WriteImageToDisk(((BitmapDrawable)img_view.getDrawable()).getBitmap(),ex.get(0).getPhoto());
writeImage.WriteImageToDisk(((BitmapDrawable)img_view_right.getDrawable()).getBitmap(),ex.get(0).getRightPhoto());    


public class WriteImage {

    public void WriteImageToDisk(Bitmap bitmap, String url){
        FileOutputStream outStream = null;
        File file;
        try {

            file = new File(url);
            outStream = new FileOutputStream(file);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 60, outStream);
            outStream.flush();
            outStream.close();

       } catch (FileNotFoundException e) {
           e.printStackTrace();
       } catch (IOException e) {
           e.printStackTrace();
       }
    }

}    

但它只保存第一张图片而不保存其他两张图片

为什么会这样？