Flutter iOS端视频相册选择器二次选择崩溃问题求助

• Flutter版本：3.13.2
• 使用插件：image_picker 1.0.4
• 异常场景：iOS设备从相册选择视频时，首次选择正常，二次选择必定崩溃；Android设备及选择图片时无此问题
• 崩溃日志：Modifications to the layout engine must not be performed from a background thread after it has been accessed from the main thread
• 相关代码：

TextButton(
  onPressed: () async {
    final ImagePicker picker = ImagePicker();
    final XFile? galleryVideo =
        await picker.pickVideo(source: ImageSource.gallery);
  },
  child: Text("Pick video from gallery"),
),

• 已尝试操作：升级Flutter及插件至最新版本，问题未解决

1. 强制在主线程执行视频选择操作
   崩溃日志指向后台线程修改UI布局，可将picker调用包裹在WidgetsBinding.instance.runOnUiThread中，确保操作在主线程执行：

   TextButton(
     onPressed: () async {
       await WidgetsBinding.instance.runOnUiThread(() async {
         final ImagePicker picker = ImagePicker();
         final XFile? galleryVideo =
             await picker.pickVideo(source: ImageSource.gallery);
       });
     },
     child: Text("Pick video from gallery"),
   ),
   

2. 复用ImagePicker实例
   每次创建新实例可能导致iOS侧资源未正确释放，尝试全局复用实例：

   // 在组件外部或State类中定义全局实例
   final ImagePicker _picker = ImagePicker();
   
   // 按钮点击逻辑
   TextButton(
     onPressed: () async {
       final XFile? galleryVideo =
           await _picker.pickVideo(source: ImageSource.gallery);
     },
     child: Text("Pick video from gallery"),
   ),
   

3. 同步Flutter引擎状态
   在选择视频前后手动触发UI状态同步，避免线程冲突：

   TextButton(
     onPressed: () async {
       WidgetsBinding.instance.ensureVisualUpdate();
       final XFile? galleryVideo =
           await _picker.pickVideo(source: ImageSource.gallery);
       WidgetsBinding.instance.addPostFrameCallback((_) {
         // 处理视频选择后的逻辑，比如更新组件状态
       });
     },
     child: Text("Pick video from gallery"),
   ),
   

4. 检查iOS原生配置
   确认Info.plist中相册权限配置正确，避免权限逻辑导致的线程冲突：

   <key>NSPhotoLibraryUsageDescription</key>
   <string>需要访问相册选择视频</string>
   

内容的提问来源于stack exchange，提问作者Tarun Khatri