Android 11 mkdir操作无效怎么办

我们都知道android11之后无法随意访问手机目录，所以这会举一个简单创建指定类型路径的方法：

 //保存文件到指定路径保存到相册
    public String saveImageToGallery(Bitmap bitmap, String type) {
        Log.d(TAG, "saveImageToGallery: ");
        // 首先保存图片
        File externalFileRootDir = getExternalFilesDir(null);
        do {
            externalFileRootDir = Objects.requireNonNull(externalFileRootDir).getParentFile();
        } while (Objects.requireNonNull(externalFileRootDir).getAbsolutePath().contains("/Android"));

        String saveDir = Objects.requireNonNull(externalFileRootDir).getAbsolutePath();
        Log.d(TAG, "saveImageToGallery saveDir: " + saveDir);
        String storePath = saveDir + File.separator + "dearxy";
        File appDir = new File(storePath);
        if (!appDir.exists()) {
            appDir.mkdirs();
        }
        String fileName = "";
        if ("jpg".equals(type)) {
            fileName = System.currentTimeMillis() + ".jpg";
        } else {
            fileName = System.currentTimeMillis() + ".png";
        }

        File file;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
            String path = Environment.getExternalStoragePublicDirectory(DIRECTORY_PICTURES).getPath();
            file = new File(path, fileName);
            try {
                FileOutputStream fos = new FileOutputStream(file);
                //通过io流的方式来压缩保存图片
                if ("jpg".equals(type)) {
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
                } else {
                    bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
                }
                fos.flush();
                fos.close();

//                MediaStore.Images.Media.insertImage(getContentResolver(),
//                        file.getAbsolutePath(), fileName, null);
//                // 最后通知图库更新
//                sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE,
//                        Uri.fromFile(new File(file.getPath()))));
            } catch (IOException e) {
                e.printStackTrace();
            }
            Log.d(TAG, "saveImageToGallery: path" + file.getAbsolutePath());
            return file.getAbsolutePath();
        } else {
            file = new File(appDir, fileName);
            try {
                FileOutputStream fos = new FileOutputStream(file);
                //通过io流的方式来压缩保存图片
                if ("jpg".equals(type)) {
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
                } else {
                    bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
                }
                fos.flush();
                fos.close();
//                MediaScannerConnection.scanFile(PhotoTranDealActivity.this,
//                        new String[]{file.toString()},
//                        new String[]{file.getName()}, null);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return file.getAbsolutePath();
    }

android 11手机图片保存成功