如何在用户离线时尝试将数据添加/上传到 Firebase 时显示错误？

Posted 2023-02-22

【中文标题】如何在用户离线时尝试将数据添加/上传到 Firebase 时显示错误？

【英文标题】：how to show error when trying to add/upload data to firebase in flutter when user is offline?

【发布时间】：2020-11-10 02:19:57

【问题描述】：

当用户尝试添加文档或将图像上传到 firestore 云/firebase 存储时，我基本上是在尝试显示警报对话框。我尝试使用 try 和 catch 块以及 .catchError() 进行尝试，但它不起作用，它基本上是在获得 Internet 连接后执行此操作。我想要做的是显示一个警报对话框并取消该过程，即使用户恢复连接（他必须再次重复上传过程）。这是我的代码示例：

这是用于挑选和上传图片：

 Future _getImage(bool isCamera) async 
    var pickedImage;
    try 
      if (isCamera)
        pickedImage =
            await picker.getImage(source: ImageSource.camera, imageQuality: 20);
      else
        pickedImage = await picker.getImage(
            source: ImageSource.gallery, imageQuality: 20);

      if (pickedImage != null) 
        _uploadAndSetUrl(File(pickedImage.path));
      
     catch (e) 
      print('error here');
    
  

  Future _uploadAndSetUrl(File image) async 
    try 
      _uploadingStatus(true);
      StorageUploadTask uploadTask = _bookImageRef.putFile(image);
      StorageTaskSnapshot taskSnapshot = await uploadTask.onComplete;
      String downloadAddress = await _bookImageRef.getDownloadURL();
      _uploadingStatus(false);
      setState(() 
        _imageUrl = downloadAddress;
      );
      print(_imageUrl);
     on PlatformException catch (e) 
      print('error: $e');
     catch (e) 
      print('No image added');
    
  

还有另一种将文档添加到 Firestore 云的方法。有什么办法吗？

提前谢谢你！

【参考方案1】：

试试这个，

import 'dart:io';

Future _getImage(bool isCamera) async 
    var pickedImage;
    try 
      if (isCamera)
        pickedImage =
            await picker.getImage(source: ImageSource.camera, imageQuality: 20);
      else
        pickedImage = await picker.getImage(
            source: ImageSource.gallery, imageQuality: 20);

      if (pickedImage != null) 
      try 
        final result = await InternetAddress.lookup('google.com');
      if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) 
        _uploadAndSetUrl(File(pickedImage.path));
       
     on SocketException catch (_) 
    showDialog(
          context: context,
          builder: (context) => AlertDialog(
            title: Text("Connection Error !"),
            content: Text("Please connect to the internet."),
          )
      );
 
        
      
     catch (e) 
      print('error here');
    
  

【讨论】：

如果有帮助请告诉我