Description:

lifecycle

lifecycle #
Lifecycle support for Flutter widgets.
Supported widgets #

StatefulWidget.
StatelessWidget(include Dialog).
PageView/TabBarView and it's children.
Nested PageView.
Navigator(Navigator 2.0 pages api).
Child of ListView/GridView/CustomScrollView.

Supported lifecycle event #
enum LifecycleEvent {
push,
visible,
active,
inactive,
invisible,
pop,
}
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Getting Started #
Install #

Depend on it

dependencies:
lifecycle: any # replace 'any' with version number
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Install it

flutter pub get

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.
import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
navigatorObservers: [defaultLifecycleObserver],
...
);
}
}
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StatefulWidget


Use mixin(Recommend)

import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';

// mixin LifecycleAware and LifecycleMixin on State
class _State extends State<MyStatefulWidget> with LifecycleAware, LifecycleMixin {
@override
void onLifecycleEvent(LifecycleEvent event) {
print(event);
}

@override
Widget build(BuildContext context) {
return Scaffold();
}
}
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Use wrapper

import 'package:flutter/material.dart';
import 'package:lifecycle/lifecycle.dart';

// Wrap widget with LifecycleWrapper
class _State extends State<MyStatefulWidget> {
@override
Widget build(BuildContext context) {
return LifecycleWrapper(
onLifecycleEvent: (event) {
print(event);
},
child: Scaffold(),
);
}
}
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StatelessWidget/Dialog

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(),
);
},
);
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PageView/TabBarView

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<MyPageView> {
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(),
),
],
),
),
);
}
}

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Nested PageView

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<NestedPageView> with SingleTickerProviderStateMixin {
PageController _pageController;
TabController _tabController;

final List<Tab> myTabs = <Tab>[
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: <Widget>[
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(),
),
],
),
),
),
],
),
),
);
}
}

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ListView

@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],
),
),
);
},
),
);
}
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Other APIs #

Iterates routes.

defaultLifecycleObserver.iterateRoutes(bool Function(route) callback);
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Remove a route.

defaultLifecycleObserver.removeRoute<T>(Route route, [T? result]);
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Dispose a LifecycleObserver when it will never be used.

defaultLifecycleObserver.dispose();
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License

For personal and professional use. You cannot resell or redistribute these repositories in their original state.

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