[Bug report] file.length() returns incorrect image size on iOS

[lm83680]

Version

3.7.1

Platforms

iOS

Device Model

iPhone13 (ios 18)

flutter info

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[✓] Connected device (4 available) [6.0s]
    • Leo iPhone 13 EM (mobile)       • 00008110-000544913C8A201E • ios            • iOS 18.7.2 22H124
    • macOS (desktop)                 • macos                     • darwin-arm64   • macOS 15.7.2 24G325 darwin-arm64
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    • Chrome (web)                    • chrome                    • web-javascript • Google Chrome 143.0.7499.110

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• No issues found!

How to reproduce?

...// Ignore；读取用例图片
final int size = await file.length();
print(size);  // 8547919

如果我使用官包image_picker读取，它将正确获得大小

XFile? x = await ImagePicker().pickImage(source: ImageSource.gallery);
print((await x?.length()));  // 3458909

可复现的图像，ios 相册显示 [3240 x 2160 3.5MB]

Logs

使用 Example code 将得到打印一下内容

flutter: PhotoManager Image Path: /private/var/mobile/Containers/Data/Application/F962640C-6440-4DAF-8215-A7DE7E6E91B8/tmp/flutter-images/43ef903f8dfa82b4aef16f08770867a2_exif.jpg
flutter: PhotoManager Image Size: 8547919
flutter: ImagePicker Image Path: /private/var/mobile/Containers/Data/Application/F962640C-6440-4DAF-8215-A7DE7E6E91B8/tmp/image_picker_C9B9F54D-9AAA-4DED-9B25-7240BB041212-9624-00000496E2AA7A73.jpg
flutter: ImagePicker Image Size: 3458909

Example code (optional)

/// 实际上并不需要UI，但为了直观看出是同一张图片，可以用该Example
class ImagePickerPage extends StatefulWidget {
  @override
  _ImagePickerPageState createState() => _ImagePickerPageState();
}

class _ImagePickerPageState extends State<ImagePickerPage> {
  File? _photoManagerImage;
  File? _imagePickerImage;

  // 异步加载图片
  Future<void> getImage() async {
    // 使用 photo_manager 获取相册图片
    final List<AssetEntity> entities = await PhotoManager.getAssetListPaged(page: 0, pageCount: 1);
    final File? photoManagerFile = await entities.first.file;
    print("PhotoManager Image Path: ${photoManagerFile?.path}");
    print("PhotoManager Image Size: ${await photoManagerFile?.length()}");

    // 使用 image_picker 获取相册图片
    XFile? xFile = await ImagePicker().pickImage(source: ImageSource.gallery);
    final File imagePickerFile = File(xFile?.path ?? '');
    print("ImagePicker Image Path: ${imagePickerFile.path}");
    print("ImagePicker Image Size: ${await imagePickerFile.length()}");

    // 更新状态，渲染图片
    setState(() {
      _photoManagerImage = photoManagerFile;
      _imagePickerImage = imagePickerFile;
    });
  }

  @override
  void initState() {
    super.initState();
    // 在页面加载时获取图片
    getImage();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("异步加载图片"),
      ),
      body: Center(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            // 左侧显示 PhotoManager 图片
            if (_photoManagerImage != null)
              Image.file(
                _photoManagerImage!,
                width: 150,
                height: 150,
              ),
            SizedBox(width: 20), // 两个图片之间的间距
            // 右侧显示 ImagePicker 图片
            if (_imagePickerImage != null)
              Image.file(
                _imagePickerImage!,
                width: 150,
                height: 150,
              ),
          ],
        ),
      ),
    );
  }
}

Contact

No response

[fluttercandies-dev]

AI Summary: 用户报告在 iOS 18 上，photo_manager 获取的图片文件大小不正确，file.length() 返回值远超实际大小，而 image_picker 正常。

[AlexV525]

file -> originalFile

[lm83680]

file -> originalFile

thank