安卓 保存Bitmap图片至本地并获得本地路径

 public void saveBitmap(Bitmap bitmap) {
        // 首先保存图片
        File appDir = new File(Environment.getExternalStorageDirectory(),"zxing_image");
        if (!appDir.exists()) {
            appDir.mkdir();
        }
        String fileName = "zxing_image" + ".png";
        file = new File(appDir, fileName);
        try {
            FileOutputStream fos = new FileOutputStream(file);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
            fos.flush();
            fos.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 把文件插入到系统图库
        try {
            MediaStore.Images.Media.insertImage(this.getContentResolver(), file.getAbsolutePath(), fileName, null);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        // 通知图库更新
        sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + "/sdcard/namecard/")));
    }