android中保存Bitmap图片到指定文件夹中的方法

   public void saveBitmapToFile(String path, Bitmap bm, String picName) {

        File f = new File(path, picName);
        FileOutputStream out = null;

        try {
            out = new FileOutputStream(f);
            bm.compress(Bitmap.CompressFormat.PNG, 90, out);
            out.flush();

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

在这里还需要两个权限：