Question

我的应用从Firebase存储获取图像。如果没有图像，我希望能够处理该错误。但是我似乎无法正常工作。

我尝试过尝试捕获。

我已经尝试过了

Future<dynamic> getImage(int index){
      return FirebaseStorage.instance.ref().child(widget.snap[index].data['英文品名']+".jpg").getDownloadURL().catchError((onError){
        print(onError);
      }); 
 }

还有这个

 Future<dynamic> getImage(int index){
   var imageStream;
   try {
       imageStream = FirebaseStorage.instance.ref().child(widget.snap[index].data['英文品名']+".jpg").getDownloadURL();    
   } catch (e) {
     print(e);
   }
   return imageStream;
 }

但是我总是遇到未处理的异常错误，我的应用程序崩溃了。

E/StorageException(11819): StorageException has occurred.
E/StorageException(11819): Object does not exist at location.
E/StorageException(11819):  Code: -13010 HttpResult: 404
E/StorageException(11819): StorageException has occurred.
E/StorageException(11819): Object does not exist at location.
E/StorageException(11819):  Code: -13010 HttpResult: 404
E/StorageException(11819): {  "error": {    "code": 404,    "message": "Not Found.  Could not get object",    "status": "GET_OBJECT"  }}
E/StorageException(11819): java.io.IOException: {  "error": {    "code": 404,    "message": "Not Found.  Could not get object",    "status": "GET_OBJECT"  }}

如何处理此异常？ Image of exception in VS Code

Answer 1

根据图片的大小，上传文件需要不同的时间。所以很可能你的错误是因为 async 和 await 的错误组合。此代码适用于我。

Future<String> uploadSingleImage(File file) async {
    //Set File Name
    String fileName = DateTime.now().millisecondsSinceEpoch.toString() +
        AuthRepository.getUser().uid +
        '.jpg';
    
    //Create Reference
    Reference reference = FirebaseStorage.instance
        .ref()
        .child('Single Post Images')
        .child(fileName);

    //Now We have to check status of UploadTask
    UploadTask uploadTask = reference.putFile(file);
    
    String url;
    await uploadTask.whenComplete(() async {
      url = await uploadTask.snapshot.ref.getDownloadURL();
    });
    print('before return');
    return url;
  }

Answer 2

抛出错误是因为您试图在尚未创建的时间访问下载 url。

您可以将上传代码封装在 if 语句中，如下例所示。这样可以保证上传任务成功完成。

 if(storageRef
        .child(folderName)
        .putFile(fileName).isSuccessful)
      {
        url = await storage.child("folderName").child(fileName).getDownloadURL();
      }

如何处理Firebase Storage StorageException

2 个答案: