https://github.com/chenenyu/lifecycle
Lifecycle support for Flutter widgets.
https://github.com/chenenyu/lifecycle
flutter lifecycle navigator observer page route widget
Last synced: 2 months ago
JSON representation
Lifecycle support for Flutter widgets.
- Host: GitHub
- URL: https://github.com/chenenyu/lifecycle
- Owner: chenenyu
- License: apache-2.0
- Created: 2020-09-22T12:03:31.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2025-03-28T12:29:04.000Z (about 1 year ago)
- Last Synced: 2025-10-23T07:34:07.699Z (6 months ago)
- Topics: flutter, lifecycle, navigator, observer, page, route, widget
- Language: Dart
- Homepage: https://pub.dev/packages/lifecycle
- Size: 293 KB
- Stars: 57
- Watchers: 4
- Forks: 9
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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# lifecycle
Lifecycle support for Flutter widgets.
### Supported widgets
- [x] `StatefulWidget`.
- [x] `StatelessWidget`(include `Dialog`).
- [x] `PageView/TabBarView` and it's children.
- [x] Nested `PageView`.
- [x] `Navigator`(Navigator 2.0 pages api).
- [x] Child of `ListView/GridView/CustomScrollView`.
### Supported lifecycle event
```dart
enum LifecycleEvent {
push,
visible,
active,
inactive,
invisible,
pop,
}
```
## Getting Started
### Install
1. Depend on it
```yaml
dependencies:
lifecycle: any # replace 'any' with version number
```
2. Install it
`flutter pub get`
3. Import it
`import 'package:lifecycle/lifecycle.dart';`
### Usage
**First of all, you should register an observer in `WidgetsApp`/`MaterialApp`, and an observer can only be used by one `Navigator`, if you have your own `Navigator`, please use a new instance of LifecycleObserver.**
```dart
import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
navigatorObservers: [defaultLifecycleObserver],
...
);
}
}
```
* StatefulWidget
1. Use mixin(Recommend)
```dart
import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';
// mixin LifecycleAware and LifecycleMixin on State
class _State extends State with LifecycleAware, LifecycleMixin {
@override
void onLifecycleEvent(LifecycleEvent event) {
print(event);
}
@override
Widget build(BuildContext context) {
return Scaffold();
}
}
```
2. Use wrapper
```dart
import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';
// Wrap widget with LifecycleWrapper
class _State extends State {
@override
Widget build(BuildContext context) {
return LifecycleWrapper(
onLifecycleEvent: (event) {
print(event);
},
child: Scaffold(),
);
}
}
```
* StatelessWidget/Dialog
```dart
import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';
// Normal StatelessWidget
class MyStatelessWidget extends StatelessWidget {
@override
Widget build(BuildContext context) {
return LifecycleWrapper(
onLifecycleEvent: (event) {
print(event);
},
child: Scaffold(),
);
}
}
// Dialog
showDialog(
context: context,
routeSettings: RouteSettings(name: 'dialog'),
builder: (context) {
return LifecycleWrapper(
onLifecycleEvent: (event) {
print(event);
},
child: Dialog(),
);
},
);
```
* PageView/TabBarView
```dart
import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';
class MyPageView extends StatefulWidget {
MyPageView({Key key}) : super(key: key);
_MyPageViewState createState() => _MyPageViewState();
}
class _MyPageViewState extends State {
PageController _pageController;
@override
void initState() {
super.initState();
_pageController = PageController();
}
@override
void dispose() {
_pageController.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('MyPageView'),
),
// Wrap PageView
body: PageViewLifecycleWrapper(
child: PageView(
controller: _pageController,
children: [
// Wrap child of PageView
ChildPageLifecycleWrapper(
index: 0,
wantKeepAlive: true,
onLifecycleEvent: (event) {
print('Page@0#${event.name}');
},
child: Container(),
),
ChildPageLifecycleWrapper(
index: 1,
wantKeepAlive: true,
onLifecycleEvent: (event) {
print('Page@1#${event.name}');
},
child: Container(),
),
],
),
),
);
}
}
```
* Nested PageView
```dart
import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';
class NestedPageView extends StatefulWidget {
NestedPageView({Key key}) : super(key: key);
_NestedPageViewState createState() => _NestedPageViewState();
}
class _NestedPageViewState extends State with SingleTickerProviderStateMixin {
PageController _pageController;
TabController _tabController;
final List myTabs = [
Tab(text: 'left'),
Tab(text: 'right'),
];
@override
void initState() {
super.initState();
_pageController = PageController();
_tabController = TabController(vsync: this, length: myTabs.length);
}
@override
void dispose() {
_pageController.dispose();
_tabController.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('NestedPageView'),
bottom: TabBar(
controller: _tabController,
tabs: myTabs,
),
),
body: PageViewLifecycleWrapper( // Outer PageView
child: TabBarView(
controller: _tabController,
children: [
ChildPageLifecycleWrapper(
index: 0,
wantKeepAlive: true,
onLifecycleEvent: (event) {
print('OuterPage@0#${event.name}');
},
child: Container(),
),
ChildPageLifecycleWrapper(
index: 1,
wantKeepAlive: true,
onLifecycleEvent: (event) {
print('OuterPage@1#${event.name}');
},
child: PageViewLifecycleWrapper( // Inner PageView
child: PageView(
controller: _pageController,
children: [
ChildPageLifecycleWrapper(
index: 0,
wantKeepAlive: false,
onLifecycleEvent: (event) {
log.add('InnerPage@0#${event.name}');
},
child: Container(),
),
ChildPageLifecycleWrapper(
index: 1,
wantKeepAlive: false,
onLifecycleEvent: (event) {
log.add('InnerPage@1#${event.name}');
},
child: Container(),
),
],
),
),
),
],
),
),
);
}
}
```
* ListView
```dart
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('ListPage'),
),
body: ListView.builder(
itemCount: _data.length,
itemBuilder: (context, index) {
return ScrollViewItemLifecycleWrapper(
onLifecycleEvent: (LifecycleEvent event) {
print('ListPage(item$index)#${event.name}');
},
wantKeepAlive: false,
child: ListTile(
title: Text(
_data[index],
),
),
);
},
),
);
}
```
### Other APIs
* Iterates routes.
```
defaultLifecycleObserver.iterateRoutes(bool Function(route) callback);
```
* Remove a route.
```
defaultLifecycleObserver.removeRoute(Route route, [T? result]);
```
* Dispose a LifecycleObserver when it will never be used.
```
defaultLifecycleObserver.dispose();
```