在TextFormField验证器Flutter中调用异步函数 [英] Call async function inside TextFormField validator Flutter

问题描述

在此代码中:

TextFormField(
        .
        .
        .
        validator: (value) => doFancy();
      ),

doFancy()声明为:

Where doFancy() is declared as :

Future<something> doFancy() async{...

我如何在 TextFormField 的 validator 内调用 doFancy()，因为它是 Future 函数，并且我不能将 validator 声明为 async 吗?

How can I call doFancy() inside the validator of a TextFormField since it's a Future function and I can't declare the validator as async?

这是我所能达到的最好水平，但是我仍然遇到相同的问题.参数类型'Future< String>不能将Function(String)'分配给参数类型'String Function(String)'.

EDIT : This is the best that I reached but I still have the same issue The argument type 'Future<String> Function(String)' can't be assigned to the parameter type 'String Function(String)'.

validator: (value) async {
          return (await checkMissingId(value, context) == false)
              ?  "Username already taken"
              :  null;
        },

推荐答案

解决了移出异步函数并使用setState中处理的变量的问题.

Solved moving out the async function and working with variables handled in setState .

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