Question 252925 in Flutter Question posted in
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Flutter – I'm getting a null safety error on Future forEach

I’m getting The operator ‘[]’ isn’t defined for the type ‘Object’ on my element![‘id’].

Code:

await Future.forEach(tempList, (element) async {
          if (element!['id'] == alertId) {
            alertList!.add(element);
            screenTitle = element!['subject'] ;
          
          }
        });

How to fix this?
Thanks.

Tags:

2

Answers


  1. 0

    Is your ‘tempList’ a List or a Map?
    In case it is a List the way of calling a var named ‘id’ is element[index].id

    By the way, be careful about using "!" without checking if the value indeed is not null, it might throw an "Null check operator used on a null value" exception.

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  2. 0

    You need to check the type of element before accessing it with []. It seems that it’s not a map like it is supposed to be.

    Moreover it’s seems like you’re using null check operator ("!") on a value that can be null. It is a good pratice to ensure that your value is not null before acessing it.

    To correct that you can do it like this.

    await Future.forEach(tempList, (element) async {
          if(element != null && element is Map<String,dynamic>){
            if (element!['id'] == alertId) {
              alertList!.add(element);
              screenTitle = element!['subject'] ;
            }  
          }
        });

    I advise you to type your variables to be aware of what type you’re using for each variable and avoid this kind of error.

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