如何在initState中等待异步

本文介绍了如何在initState中等待异步的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个需要在有状态窗口小部件的initState中调用的异步函数，但是我不能使用await，因为initState不是异步的.

I have an async function that needs to be called in initState in an Stateful widget, but I cannot use await as initState is not async.

sendHealthData 是 async ，因为它从Health Api获取了一些信息，然后我需要将该信息发送到HomeSubScreen，后者是另一个 StatefulWidget .但是在创建HomeSubScreen时， sendHealthData 方法无法获取所有信息，因此，如果我尝试将参数值发送给 HomeSubScreen ，则值将为空.

sendHealthData is async as it get some information from the Health Api, and then I need to send that information to HomeSubScreen which is another StatefulWidget. But at the time the HomeSubScreen is created, the sendHealthData method didn't get all the information, so If I try to send some value in a param to the HomeSubScreen, the value will be null.

我该怎么做?

@override void initState() { super.initState(); sendHealthData(); _widgetOptions = <Widget>[ HomeSubScreen(healthData), ]; }

更新:如果添加了then()，则会出现以下错误:

Update: If I added a then() I get the following error:

NoSuchMethodError: The method 'elementAt' was called on null.

代码已更新:

@override void initState() { super.initState(); sendHealthData().then((response){ _widgetOptions = <Widget>[ HomeSubScreen(healthData), ]; }); }

推荐答案

我给您关于它的一般概念.

I'm giving you general idea of it.

@override void initState() { super.initState(); function().then((int value) { // future is completed you can perform your task }); function2(); // or you can simply call the method if you don't want anything to do after future completes } Future<int> function() async { // do something here } Future<int> function2() async { // do something here }