Flutter：如何从另一个类调用方法？

Question

我是 Dart 和 Flutter 的新手。现在我在调用另一个类的方法时遇到问题。

我尝试将方法设为静态，但该方法包含 setState() 方法，因此无法实现。

所以我必须从wallet.dart 打电话给main.dart >>> showDialogWith()

main.dart

import 'package:flutter/material.dart';
import 'dialog/operation.dart';
import 'pages/wallet.dart';

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Future showDialogWith(String dialogName) async {
    Widget dialog;
    switch (dialogName) {
      case 'operations':
        setState(() {
          dialog = OperationsDialog();
        });
        break;
        // another cases and default...
    }
    await showDialog(
        context: context,
        child: dialog,
    );
  }

  @override
  Widget build(BuildContext context) {
   body: WalletContent();
  }
}

wallet.dart

class WalletContent extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialButton(
      onPressed: () {
        // here I have to call the 'showDialogWith()' method
      },
    );
  }
}

操作.dart

class OperationsDialog extends StatefulWidget{
  OperationsDialog({Key key}) : super(key: key);

  @override
  _OperationDialogState createState() => new _OperationDialogState();
}

class _OperationDialogState extends State<OperationsDialog> {

  @override
  Widget build(BuildContext context) {
    return new SimpleDialog(
      title: new Text('Операции', textAlign: TextAlign.center),
    );
  }
}

Answer 1

您可以将函数作为参数传递。

@override
  Widget build(BuildContext context) {
  body: WalletContent(showDialogWith);
}

在您的 WalletContent 中添加一个 Function 字段并将其分配给您的 MaterialButton

class WalletContent extends StatelessWidget {
  WalletContent(this.onPressed);

  final Function onPressed;

  @override
  Widget build(BuildContext context) {
    return MaterialButton(
      onPressed: () => onPressed(...), // Pass your desired string here
    );
  }
}