如何有条件地为Flutter List分配一个值

huangapple
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英文:

How to conditionally assign a value to Flutter List

问题

如何根据recipeList的值有条件地为"ingList"赋值？

  1. class Calculator extends StatefulWidget {
  2.   List<IngredientList> recipeList;
  3.   Calculator(this.recipeList, {Key? key}) : super(key: key);
  5.   @override
  6.   State<Calculator> createState() => _CalculatorState();
  7. }
  9. class _CalculatorState extends State<Calculator> {
  10.   List<IngredientList> ingList = [];

这段代码中，根据recipeList的值，有条件地为"ingList"赋值。

英文:

How to conditionally assign a value to "ingList" based on the value of recipeList?

  1.  class Calculator extends StatefulWidget {
  2.     List&lt;IngredientList&gt; recipeList;
  3.     Calculator(this.recipeList, {Key? key}) : super(key: key);
  5.   @override
  6.   State&lt;Calculator&gt; createState() =&gt; _CalculatorState();
  7. }
  9. class _CalculatorState extends State&lt;Calculator&gt; {
  10.   List&lt;IngredientList&gt; ingList = [];

答案1

得分: 1

你可以使用 initState 来实现这个功能。

英文:

You can use initState to do that

  1. class Calculator extends StatefulWidget {
  2.   List&lt;IngredientList&gt; recipeList;
  3.   Calculator(this.recipeList, {Key? key}) : super(key: key);
  5.   @override
  6.   State&lt;Calculator&gt; createState() =&gt; _CalculatorState();
  7. }
  9. class _CalculatorState extends State&lt;Calculator&gt; {
  10.   List&lt;IngredientList&gt; ingList = [];
  12.   @override
  13.   void initState() {
  14.     super.initState();
  16.     ingList = widget.recipeList; // you can do any condition here
  17.   }
  18. }

huangapple
  • 本文由 发表于 2023年6月2日 13:14:08
  • 转载请务必保留本文链接：https://go.coder-hub.com/76387297.html
  • conditional-statements
  • flutter
  • list
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