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。
问问题
3703 次
3 回答
7
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()),
于 2020-12-02T23:42:00.290 回答
2
Based from the code of the super implementation of onClose, by default it does nothing currently.
And from the comments, it says:
/// Called before [onDelete] method. [onClose] might be used to
/// dispose resources used by the controller. Like closing events,
/// or streams before the controller is destroyed.
/// Or dispose objects that can potentially create some memory leaks,
/// like TextEditingControllers, AnimationControllers.
/// Might be useful as well to persist some data on disk.
void onClose() {}
from that I think you need to manually close your streams in YourController::onClose() override function.
于 2020-11-04T14:17:19.147 回答
0
使用 GetWorkers 时，您似乎可以安全地使用 obs。运行此代码，您会注意到，当您单击按钮几次时，每页切换只会打印一次。
void main(){
runApp(GetMaterialApp(home: TestWidget(),));
}
class TestWidget extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Center(
child: RaisedButton(
child: Text('next'),
onPressed: () => Get.to<SomeWidget>(SomeWidget()),
),
);
}
}
class SomeWidget extends StatelessWidget {
RxBool isSubscribed = false.obs;
SomeWidget() {
ever(isSubscribed, (_) => print('test'));
}
@override
Widget build(BuildContext context) {
return Center(
child: RaisedButton(
child: Text('back'),
onPressed: () {
isSubscribed.value = !isSubscribed.value;
Get.back();
},
),
);
}
}
于 2020-11-05T14:50:25.687 回答