GetX - 如何从 Get.Dialog 返回值？

Question

如何从打开对话框小部件/警报对话框的 Get.Dialog 获取返回值？

Answer 1

1. 获取材质应用程序

在你的 main.dart 中，确保MyApp返回 aGetMaterialApp而不是MaterialApp

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return GetMaterialApp( // <-- Use GetMaterialApp
      title: 'Flutter Demo',
      home: MyHomePage(title: 'Flutter Examples'),
    );
  }
}

这允许 Get 处理导航/路由，使导航方法可用，例如：Get.to()、Get.dialog()、Get.back()等。如果没有GetMaterialApp作为应用程序的根，您在调用任何导航方法时都会看到一个（令人困惑的）错误：

E/flutter (11139): [ERROR:flutter/lib/ui/ui_dart_state.cc(166)] Unhandled Exception: 
'package:flutter/src/widgets/localizations.dart': Failed assertion: 
line 453 pos 12: 'context != null': is not true.

2. Get.dialog + Get.back(结果：X)

让您的调用期望Get.dialog异步返回值...

onPressed: () async {
  // assign return value to an observable
  return lx.result.value = await Get.dialog(

...当对话框关闭时返回，其中使用通过Get.back(result: X)以下X方式返回的动态值Get.dialog：

onPressed: () => Get.back(result: true),

完整示例：

import 'package:flutter/material.dart';
import 'package:get/get.dart';

class LoginX extends GetxController {
  RxBool result = false.obs;
}

class GetDialogReturnPage extends StatelessWidget {
  final LoginX lx = Get.put(LoginX());

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GetDialog Return Example'),
      ),
      body: SafeArea(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.center,
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            Container(
              child: Obx(() => Text('Value shows here: ${lx.result.value}')),
            ),
            Container(
              alignment: Alignment.center,
              child: RaisedButton(
                child: Text('Login'),
                onPressed: () async {
                  // ** assign return value to an observable **
                  return lx.result.value = await Get.dialog(
                      AlertDialog(
                          content: Row(
                            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                            children: [
                              RaisedButton(
                                child: Text('Good Login'),
                                onPressed: () => Get.back(result: true),
                                // ** result: returns this value up the call stack **
                              ),
                              SizedBox(width: 5,),
                              RaisedButton(
                                child: Text('Bad Login'),
                                onPressed: () => Get.back(result: false),
                              ),
                            ],
                          )
                      )
                  );},
              ),
            )
          ],
        ),
      ),
    );
  }
}