flutter - GetxControllers 是否会自动关闭 obs 流?
问题描述
我正在使用以下包https://pub.dev/packages/get。我需要在 GetxController 的 onClose 中关闭我的 .obs 吗?我在文档中找不到任何关于此的内容。看着我的记忆,似乎它们正在被自动销毁。
解决方案
到目前为止,我对 GetX + Flutter 的理解...
不,您不必在 GetxControllers 的close()
方法中删除 .obs。当控制器从内存中删除时,控制器中的可观察对象的处理会自动完成。
当包含它们的小部件从小部件堆栈中弹出/从小部件树中删除(默认情况下,但可以被覆盖)时,GetX 会处理/删除 GetxControllers(及其可观察对象)。
您可以在覆盖dispose()
各种 Get 小部件的方法中看到这一点。
这是弹出/删除小部件dispose()
时运行的片段:GetX
@override
void dispose() {
if (widget.dispose != null) widget.dispose(this);
if (isCreator || widget.assignId) {
if (widget.autoRemove && GetInstance().isRegistered<T>(tag: widget.tag)) {
GetInstance().delete<T>(tag: widget.tag);
}
}
subs.cancel();
_observer.close();
controller = null;
isCreator = null;
super.dispose();
}
当您使用 Bindings 或Get.to()
使用GetPageRoute
's 时,它会按路由名称进行清理:
@override
void dispose() {
if (Get.smartManagement != SmartManagement.onlyBuilder) {
WidgetsBinding.instance.addPostFrameCallback((_) => GetInstance()
.removeDependencyByRoute("${settings?.name ?? routeName}"));
}
super.dispose();
}
测试应用
下面是一个测试应用程序,您可以将其复制/粘贴到 Android Studio / VSCode 中并运行以观察调试或运行窗口输出以获得 GETX 生命周期事件。
GetX 将记录控制器在内存中的创建和处理。
该应用程序有一个 HomePage 和 3 个 ChildPages,它们以 3 种方式使用 Get Controller,所有这些都从内存中删除:
- GetX/GetBuilder
- 获取.put
- 绑定
import 'package:flutter/material.dart';
import 'package:get/get.dart';
void main() {
// MyCounterBinding().dependencies(); // usually where Bindings happen
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return GetMaterialApp(
title: 'GetX Dispose Ex',
home: HomePage(),
);
}
}
class HomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('GetX Dispose Test'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
RaisedButton(
child: Text('GetX/Builder Child'),
onPressed: () => Get.to(ChildPage()),
),
RaisedButton(
child: Text('Get.put Child'),
onPressed: () => Get.to(ChildPutPage()),
),
RaisedButton(
child: Text('Binding Child'),
onPressed: () => Get.to(ChildBindPage()),
),
],
),
),
);
}
}
/// GETX / GETBUILDER
/// Creates Controller within the Get widgets
class ChildPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('GetX Dispose Test Counter'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Text('This is the Child Page'),
GetX<ChildX>(
init: ChildX(),
builder: (cx) => Text('Counter: ${cx.counter}', style: TextStyle(fontSize: 20),),
),
GetBuilder<ChildX>(
init: ChildX(),
builder: (cx) => RaisedButton(
child: Text('Increment'),
onPressed: cx.inc,
),
),
],
),
),
);
}
}
/// GET.PUT
/// Creates Controller instance upon Build, usable anywhere within the widget build context
class ChildPutPage extends StatelessWidget {
//final ChildX cx = Get.put(ChildX()); // wrong place to put
// see https://github.com/jonataslaw/getx/issues/818#issuecomment-733652172
@override
Widget build(BuildContext context) {
final ChildX cx = Get.put(ChildX());
return Scaffold(
appBar: AppBar(
title: Text('GetX Dispose Test Counter'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Text('This is the Child Page'),
Obx(
() => Text('Counter: ${cx.counter}', style: TextStyle(fontSize: 20),),
),
RaisedButton(
child: Text('Increment'),
onPressed: cx.inc,
)
],
),
),
);
}
}
class MyCounterBinding extends Bindings {
@override
void dependencies() {
Get.lazyPut(() => ChildX(), fenix: true);
}
}
/// GET BINDINGS
/// Normally the MyCounterBinding().dependencies() call is done in main(),
/// making it available throughout the entire app.
/// A lazyPut Controller /w [fenix:true] will be created/removed/recreated as needed or
/// as specified by SmartManagement settings.
/// But to keep the Bindings from polluting the other examples, it's done within this
/// widget's build context (you wouldn't normally do this.)
class ChildBindPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
MyCounterBinding().dependencies(); // just for illustration/example
return Scaffold(
appBar: AppBar(
title: Text('GetX Dispose Test Counter'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Text('This is the Child Page'),
Obx(
() => Text('Counter: ${ChildX.i.counter}', style: TextStyle(fontSize: 20),),
),
RaisedButton(
child: Text('Increment'),
onPressed: ChildX.i.inc,
)
],
),
),
);
}
}
class ChildX extends GetxController {
static ChildX get i => Get.find();
RxInt counter = 0.obs;
void inc() => counter.value++;
}
笔记
Get.to 与 Navigator.push
在子小部件中使用Get.put()
时,请确保您使用Get.to()
的是导航到该子小部件,而不是 Flutter 的内置Navigator.push
.
GetX 在使用GetPageRoute
时将目标小部件包装在Get.to
. 当导航离开/将小部件从堆栈中弹出时,此 Route 类将处理此路由中的控制器。如果您使用Navigator.push
,则不会涉及 GetX 并且您不会获得此自动清理。
导航器.push
onPressed: () => Navigator.push(context, MaterialPageRoute(
builder: (context) => ChildPutPage())),
到达
onPressed: () => Get.to(ChildPutPage()),
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