前言 正如Get官方介绍,GetX 是 Flutter 上的一个轻量且强大的解决方案:高性能的状态管理、智能的依赖注入和便捷的路由管理。GetX 有3个基本原则:
性能: GetX 专注于性能和最小资源消耗。
效率: GetX 的语法非常简捷,并保持了极高的性能,能极大缩短你的开发时长。
结构: GetX 可以将界面、逻辑、依赖和路由之间低耦合,逻辑更清晰,代码更容易维护。
这篇文章主要是介绍下GetX的用法。
一.安装 目前get最新的版本是4.6.6。安装方式如下:
dependencies: get: ^4.6.6
二.从一个计时器开始 但我们创建一个flutter工程的时候,系统会生成一个计时器的示例代码,代码大致如下(我删除了部分注释代码):
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
useMaterial3: true,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headlineMedium,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
主要功能是点击+按钮,每次计时器的个数+1.点击按钮之后,调用setState方法刷新_counter变量。
下面我们看一下如何使用getx来实现上述的功能:
第一步:把系统的MaterialApp改成GetMaterialApp:
void main() => runApp(GetMaterialApp(home: Home()));
第二步:创建业务类,我们把_counter变量放在Controller类中:
class Controller extends GetxController{ var counter = 0.obs; increment() => counter++; }
第三步:使用StatelessWidget代替StatefulWidget,节省下内存。修改之后的完整代码如下:
import 'package:flutter/material.dart';
import 'package:get/get.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return GetMaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
useMaterial3: true,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class Controller extends GetxController{
var counter = 0.obs;
incrementCounter()=>counter++;
}
class MyHomePage extends StatelessWidget {
const MyHomePage({super.key, required this.title});
final String title;
@override
Widget build(BuildContext context) {
final Controller controller = Get.put(Controller());
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: Text(title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Obx(() => Text(
'${controller.counter}',
style: Theme.of(context).textTheme.headlineMedium,
)),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: (){
controller.incrementCounter();
},
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
三.Getx路由管理
1.普通路由导航
1.导航到新的页面
假如我们有一个新页面NextScreenPage,代码如下
import 'package:flutter/material.dart';
class NextScreenPage extends StatelessWidget {
const NextScreenPage({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: const Text("新页面"),
),
body: Container(
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
从当前页面跳转到NextScreenPage页面,代码如下:
Get.to(()=>NextScreen());
2.关闭SnackBars、Dialogs、BottomSheets或任何你通常会用Navigator.pop(context)关闭的东西 还是以上面的代码为例,我们添加一个返回按钮,点击返回按钮的时候,回到当前页面。主需要在按钮的点击事件中添加如下代码即可:
Get.back();
NextScreenPage页面完整代码如下:
import 'package:flutter/material.dart';
import 'package:get/get.dart';
class NextScreenPage extends StatelessWidget {
const NextScreenPage({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: const Text("新页面"),
),
body: Center(
child: ElevatedButton(onPressed: (){
Get.back();
}, child: const Text("返回上一个页面")),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}