Introduction to GetxController
In the actual project development process, it is impossible for us to process the UI code and business logic together, which will be fatal to the project structure, code readability, and later maintenance. Fortunately, it provides us GetX
with GetxController
, GetxController
the main function is to separate UI code from business logic.
Three ways to use GetxController
Here we mainly explain GetxController
the three ways to use dynamic data acquisition and the way to update data
Step 1: Application entry setting
import 'package:flutter/material.dart';
import 'package:flutter_getx_example/GetXControllerExample/GetXControllerExample.dart';
import 'package:get/get.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return GetMaterialApp(
title: "GetX",
home: GetXControllerExample(),
);
}
}
Step 2: Define the controller to inherit from GetxController
import 'package:flutter_getx_example/ObxCustomClassExample/Teacher.dart';
import 'package:get/get.dart';
class MyController extends GetxController {
// 第一种
// var teacher = Teacher();
//
// void convertToUpperCase() {
// teacher.name.value = teacher.name.value.toUpperCase();
// }
// 第二种
// var teacher = Teacher(name: "Jimi", age: 18).obs;
// void convertToUpperCase() {
// teacher.update((val) {
// teacher.value.name = teacher.value.name.toString().toUpperCase();
// });
// }
// 第三种
var teacher = Teacher();
void convertToUpperCase() {
teacher.name.value = teacher.name.value.toUpperCase();
update();//主动的去调用更新.也可以在update()增加一个id的数组.在调用的使用只有当调用显示的id包含在该id数组里面的时候,才会有效.
}
}
Step 3: Instantiate the controller and use
import 'package:flutter/material.dart';
import 'package:flutter_getx_example/GetXControllerExample/MyController.dart';
import 'package:get/get.dart';
class GetXControllerExample extends StatelessWidget {
// 第一种
MyController myController = Get.put(MyController());
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("GetX Obx---GetXController"),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
// 第一种==>被动的
// Obx(() => Text(
// "我的名字是 ${myController.teacher.name}",
// style: TextStyle(color: Colors.red, fontSize: 30),
// )),
// 第二种==>被动的
// GetX<MyController>(
// init: MyController(),
// builder: (controller) {
// return Text(
// "我的名字是 ${controller.teacher.name}",
// style: TextStyle(color: Colors.green, fontSize: 30),
// );
// },
// ),
/*
Obx和GetX<MyController>和GetBuilder<MyController>的区别:
Obx的Controller作用域是在外面的,而GetX<MyController>的Controller作用域只限于当前函数体里面的.
GetBuilder<MyController>和GetX<MyController>的区别在于GetBuilder<MyController>的性能会更高一点
*/
// 第三种==>主动的
GetBuilder<MyController>(
//id:**,该id如何在update()函数数据里面存在的时候,这里的属性值才会跟着发生变化.默认不写的话,是包含的.
init: myController,//init方法可以省略不要
builder: (controller) {
return Text(
"我的名字是 ${controller.teacher.name}",
style: TextStyle(color: Colors.green, fontSize: 30),
);
},
),
SizedBox(height: 20,),
ElevatedButton(
onPressed: () {
// 第一种
myController.convertToUpperCase();
// 第二种
// Get.find<MyController>().convertToUpperCase();
},
child: Text("转换为大写"))
],
),
),
);
}
}
GetxController life cycle
The life cycle mainly explained here GetxController
includes initialization , loading completion , destruction , etc.
Step 1: Application entry setting
import 'package:flutter/material.dart';
import 'package:flutter_getx_example/GetXControllerLifecycleMethodsExample/GetXControllerLifecycleMethodExample.dart';
import 'package:get/get.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return GetMaterialApp(
title: "GetX",
home: GetXControllerLifecycleMethodExample(),
);
}
}
Step 2: Define the controller to inherit from GetxController
import 'package:get/get.dart';
class MyLifecycleController extends GetxController {
var count = 0;
void increment() async {
await Future.delayed(Duration(milliseconds: 3000));
count++;
update();
}
void cleanTask() {
print("清除了任务");
}
}
Step 3: Override the GetxController lifecycle method
@override
void onInit() {
// TODO: implement onInit
print("初始化");
super.onInit();
}
@override
void onReady() {
// TODO: implement onReady
print("加载完成");
super.onReady();
}
@override
void onClose() {
// TODO: implement onClose
print("控制器被释放");
super.onClose();
}
Step 4: Instantiate the controller and use
import 'package:flutter/material.dart';
import 'package:flutter_getx_example/GetXControllerLifecycleMethodsExample/MyLifecycleController.dart';
import 'package:get/get.dart';
class GetXControllerLifecycleMethodExample extends StatelessWidget {
MyLifecycleController myLifecycleController = Get.put(MyLifecycleController());
@override
Widget build(BuildContext context) {
print("build");
return Scaffold(
appBar: AppBar(
title: Text("GetXControllerLifecycleMethod"),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
GetBuilder<MyLifecycleController>(
initState: (data) => myLifecycleController.increment(),
dispose: (_) => myLifecycleController.cleanTask(),
builder: (controller) {
return Text(
"计数器值为: ${myLifecycleController.count}",
style: TextStyle(color: Colors.green, fontSize: 30),
);
},
),
],
),
),
);
}
}
console output
flutter: 初始化
[GETX] Instance "MyLifecycleController" has been created
[GETX] Instance "MyLifecycleController" has been initialized
[GETX] Instance "GetMaterialController" has been created
[GETX] Instance "GetMaterialController" has been initialized
flutter: build
flutter: 加载完成
flutter: build
flutter: build
GetxController UniqueID
During the development process, we will encounter a situation where the same attribute is referenced in multiple places, but I only want to update a certain place separately, so it can be UniqueID
used
Step 1: Application entry setting
import 'package:flutter/material.dart';
import 'package:flutter_getx_example/GetXControllerUniqueIDExample/GetXControllerUniqueIDExample.dart';
import 'package:get/get.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return GetMaterialApp(
title: "GetX",
home: GetXControllerUniqueIDExample(),
);
}
}
Step 2: Define the controller to inherit from GetxController, and define uniqueID
import 'package:get/get.dart';
class CountController extends GetxController {
var count = 0;
void increment() {
count++;
update(['jimi_count']);
}
}
Step 3: Instantiate the controller and use
import 'package:flutter/material.dart';
import 'package:flutter_getx_example/GetXControllerUniqueIDExample/CountConroller.dart';
import 'package:get/get.dart';
class GetXControllerUniqueIDExample extends StatelessWidget {
CountController countController = Get.put(CountController());
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("GetX Obx---GetXController"),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
GetBuilder<CountController>(
builder: (controller) {
return Text(
"计数器值为: ${controller.count}",
style: TextStyle(color: Colors.red, fontSize: 30),
);
},
),
GetBuilder<CountController>(
id: 'jimi_count',
builder: (controller) {
return Text(
"计数器值为: ${controller.count}",
style: TextStyle(color: Colors.green, fontSize: 30),
);
},
),
SizedBox(height: 20,),
ElevatedButton(
onPressed: () => countController.increment(),
child: Text("增加"))
],
),
),
);
}
}