来自flutter_image_compress的FlutterImageCompress.compressAndGetFile永远不会成功地将输出写入任何iPad上的targetPath。
完全相同的代码适用于iPhone和所有Android手机和平板电脑。
下面是未按预期运行的函数：

Future<File?> _compressFile(File file) async {
    final String path =
        '${widget.directoryPath}/users/${User().id}/images/tmp.jpeg';
    final File? result = await FlutterImageCompress.compressAndGetFile(
        file.absolute.path, path,
        quality: 50);

    print(result);

    try {
      await result!
          .length(); // from the docs: The returned file may be null. In addition, please decide for yourself whether the file exists.
      print(
          'Compress file from ${(await file.length()) / 1e6} Mb to ${(await result.length()) / 1e6} Mb');
    } catch (e) {
      print('File original size ${(await file.length()) / 1e6} Mb');
      print('Error while compressing file: $e');
      return null;
    }

    return result;
  }

在iPad上，我总是有以下输出：

flutter: File: '/Users/adrkacz/Library/Developer/CoreSimulator/Devices/C2E0A11D-6BC4-47FF-BCAE-A15709073B9B/data/Containers/Data/Application/587B3363-828F-489F-8490-B2099F02D985/Documents/users/a38ededd-5fd5-4639-a303-40c4289cace8/images/tmp.jpeg'
flutter: File original size 1.74672 Mb
flutter: Error while compressing file: PathNotFoundException: Cannot retrieve length of file, path = '/Users/adrkacz/Library/Developer/CoreSimulator/Devices/C2E0A11D-6BC4-47FF-BCAE-A15709073B9B/data/Containers/Data/Application/587B3363-828F-489F-8490-B2099F02D985/Documents/users/a38ededd-5fd5-4639-a303-40c4289cace8/images/tmp.jpeg' (OS Error: No such file or directory, errno = 2)

如你所见：

1. FlutterImageCompress.compressAndGetFile没有返回null，它在预期位置返回File对象
2. file不是空文件，程序可以读取其长度（1.74672 Mb）
3. result没有长度，这意味着它不存在，我们可以从输出错误中确认。
   可能出现多种问题：
   1.在iPad上，directoryPath不一致，不应使用。
   1.在iPad上，压缩算法无法写入内存。

• 注：widget.directoryPath的值为(await getApplicationDocumentsDirectory()).path*