Flutter How to check if Sliver AppBar is expanded or collapsed?
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0
down vote
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I am using a SliverAppBar in Flutter, with a background widget.
The thing is When it's expanded, the title and icons (leading and actions) should be white in order to be seen correctly, and when it's collapsed, they should be changed to black.
Any ideas on how I can get a bool out of it? Or other ways of resolving this problem.
Thank you.
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.body,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
bool isAppBarExpanded = false;
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: itemColor, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: itemColor, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: itemColor, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.body),
],
),
);
}
}
flutter flutter-sliver asked 2 days ago
Sina Seirafi
72
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
0
down vote
favorite
I am using a SliverAppBar in Flutter, with a background widget.
The thing is When it's expanded, the title and icons (leading and actions) should be white in order to be seen correctly, and when it's collapsed, they should be changed to black.
Any ideas on how I can get a bool out of it? Or other ways of resolving this problem.
Thank you.
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.body,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
bool isAppBarExpanded = false;
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: itemColor, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: itemColor, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: itemColor, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.body),
],
),
);
}
}
asked 2 days ago
Sina Seirafi
72
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Please Add Your Code also !
– anmol.majhail
2 days ago
@anmol.majhail Thanks for the heads up.
– Sina Seirafi
2 days ago
stackoverflow.com/a/51927031/10269042
– anmol.majhail
2 days ago
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I am using a SliverAppBar in Flutter, with a background widget.
The thing is When it's expanded, the title and icons (leading and actions) should be white in order to be seen correctly, and when it's collapsed, they should be changed to black.
Any ideas on how I can get a bool out of it? Or other ways of resolving this problem.
Thank you.
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.body,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
bool isAppBarExpanded = false;
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: itemColor, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: itemColor, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: itemColor, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.body),
],
),
);
}
}
asked 2 days ago
Sina Seirafi
72
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I am using a SliverAppBar in Flutter, with a background widget.
The thing is When it's expanded, the title and icons (leading and actions) should be white in order to be seen correctly, and when it's collapsed, they should be changed to black.
Any ideas on how I can get a bool out of it? Or other ways of resolving this problem.
Thank you.
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.body,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
bool isAppBarExpanded = false;
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: itemColor, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: itemColor, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: itemColor, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.body),
],
),
);
}
}
asked 2 days ago
Sina Seirafi
72
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 days ago
Sina Seirafi
72
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 days ago
asked 2 days ago
Sina Seirafi
72
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 days ago
Sina Seirafi
72
asked 2 days ago
Sina Seirafi
72
72
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Sina Seirafi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Please Add Your Code also !
– anmol.majhail
2 days ago
@anmol.majhail Thanks for the heads up.
– Sina Seirafi
2 days ago
stackoverflow.com/a/51927031/10269042
– anmol.majhail
2 days ago
add a comment |
Please Add Your Code also !
– anmol.majhail
2 days ago
@anmol.majhail Thanks for the heads up.
– Sina Seirafi
2 days ago
stackoverflow.com/a/51927031/10269042
– anmol.majhail
2 days ago
Please Add Your Code also !
– anmol.majhail
2 days ago
Please Add Your Code also !
– anmol.majhail
2 days ago
@anmol.majhail Thanks for the heads up.
– Sina Seirafi
2 days ago
@anmol.majhail Thanks for the heads up.
– Sina Seirafi
2 days ago
stackoverflow.com/a/51927031/10269042
– anmol.majhail
2 days ago
stackoverflow.com/a/51927031/10269042
– anmol.majhail
2 days ago
add a comment |
2 Answers
2
active
oldest
votes
up vote
0
down vote
You need to use ScrollController to achieve the desired effect
try this code
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: SliverExample(
bodyWidgets: Text('Hello Body gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg'),
backgroundWidget: Text('Hello Background'),
),
);
}
}
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.bodyWidgets,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
ScrollController _scrollController;
bool isAppBarExpanded = false;
@override
void initState() {
super.initState();
_scrollController = ScrollController()
..addListener(() => setState(() {
print('Scroll view Listener is called offset ${_scrollController.offset}');
}));
}
bool get _changecolor {
return _scrollController.hasClients
&& _scrollController.offset > (200-kToolbarHeight);
}
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
//Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
controller: _scrollController,
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: _changecolor? Colors.white: Colors.black, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: _changecolor? Colors.white: Colors.black, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: _changecolor? Colors.white: Colors.black, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.bodyWidgets),
],
),
);
}
}
answered 2 days ago
Saed Nabil
945
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
0
down vote
You can use LayoutBuilder to get sliver AppBar biggest height. When biggest.height = 80.0, it actually means sliver appbar is collapsed.
Here is a full example:
import 'package:flutter/material.dart';
void main() => runApp(MaterialApp(
home: MyApp(),
));
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
var top = 0.0;
@override
Widget build(BuildContext context) {
return Scaffold(
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return <Widget>[
SliverAppBar(
expandedHeight: 200.0,
floating: false,
pinned: true,
flexibleSpace: LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
// print('constraints=' + constraints.toString());
top = constraints.biggest.height;
return FlexibleSpaceBar(
centerTitle: true,
title: AnimatedOpacity(
duration: Duration(milliseconds: 300),
//opacity: top == 80.0 ? 1.0 : 0.0,
opacity: 1.0,
child: Text(
top.toString(),
style: TextStyle(fontSize: 12.0),
)),
background: Image.network(
"https://images.unsplash.com/photo-1542601098-3adb3baeb1ec?ixlib=rb-0.3.5&ixid=eyJhcHBfaWQiOjEyMDd9&s=5bb9a9747954cdd6eabe54e3688a407e&auto=format&fit=crop&w=500&q=60",
fit: BoxFit.cover,
));
})),
];
},body: ListView.builder(
itemCount: 100,
itemBuilder: (context,index){
return Text("List Item: " + index.toString());
},
),
));
}
}
Final result:
answered 2 days ago
Jack Sun
356
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
You need to use ScrollController to achieve the desired effect
try this code
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: SliverExample(
bodyWidgets: Text('Hello Body gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg'),
backgroundWidget: Text('Hello Background'),
),
);
}
}
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.bodyWidgets,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
ScrollController _scrollController;
bool isAppBarExpanded = false;
@override
void initState() {
super.initState();
_scrollController = ScrollController()
..addListener(() => setState(() {
print('Scroll view Listener is called offset ${_scrollController.offset}');
}));
}
bool get _changecolor {
return _scrollController.hasClients
&& _scrollController.offset > (200-kToolbarHeight);
}
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
//Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
controller: _scrollController,
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: _changecolor? Colors.white: Colors.black, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: _changecolor? Colors.white: Colors.black, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: _changecolor? Colors.white: Colors.black, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.bodyWidgets),
],
),
);
}
}
answered 2 days ago
Saed Nabil
945
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
0
down vote
You need to use ScrollController to achieve the desired effect
try this code
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: SliverExample(
bodyWidgets: Text('Hello Body gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg'),
backgroundWidget: Text('Hello Background'),
),
);
}
}
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.bodyWidgets,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
ScrollController _scrollController;
bool isAppBarExpanded = false;
@override
void initState() {
super.initState();
_scrollController = ScrollController()
..addListener(() => setState(() {
print('Scroll view Listener is called offset ${_scrollController.offset}');
}));
}
bool get _changecolor {
return _scrollController.hasClients
&& _scrollController.offset > (200-kToolbarHeight);
}
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
//Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
controller: _scrollController,
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: _changecolor? Colors.white: Colors.black, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: _changecolor? Colors.white: Colors.black, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: _changecolor? Colors.white: Colors.black, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.bodyWidgets),
],
),
);
}
}
answered 2 days ago
Saed Nabil
945
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
up vote
0
down vote
up vote
0
down vote
You need to use ScrollController to achieve the desired effect
try this code
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: SliverExample(
bodyWidgets: Text('Hello Body gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg'),
backgroundWidget: Text('Hello Background'),
),
);
}
}
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.bodyWidgets,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
ScrollController _scrollController;
bool isAppBarExpanded = false;
@override
void initState() {
super.initState();
_scrollController = ScrollController()
..addListener(() => setState(() {
print('Scroll view Listener is called offset ${_scrollController.offset}');
}));
}
bool get _changecolor {
return _scrollController.hasClients
&& _scrollController.offset > (200-kToolbarHeight);
}
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
//Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
controller: _scrollController,
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: _changecolor? Colors.white: Colors.black, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: _changecolor? Colors.white: Colors.black, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: _changecolor? Colors.white: Colors.black, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.bodyWidgets),
],
),
);
}
}
answered 2 days ago
Saed Nabil
945
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
You need to use ScrollController to achieve the desired effect
try this code
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: SliverExample(
bodyWidgets: Text('Hello Body gggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg'),
backgroundWidget: Text('Hello Background'),
),
);
}
}
class SliverExample extends StatefulWidget {
final Widget backgroundWidget;
final Widget bodyWidgets;
SliverExample({
this.backgroundWidget,
this.bodyWidgets,
});
@override
_SliverExampleState createState() => _SliverExampleState();
}
class _SliverExampleState extends State<SliverExample> {
// I need something like this
// To determine if SliverAppBar is expanded or not.
ScrollController _scrollController;
bool isAppBarExpanded = false;
@override
void initState() {
super.initState();
_scrollController = ScrollController()
..addListener(() => setState(() {
print('Scroll view Listener is called offset ${_scrollController.offset}');
}));
}
bool get _changecolor {
return _scrollController.hasClients
&& _scrollController.offset > (200-kToolbarHeight);
}
@override
Widget build(BuildContext context) {
// To change the item's color accordingly
// To be used in multiple places in code
//Color itemColor = isAppBarExpanded ? Colors.white : Colors.black;
// In my case PrimaryColor is white,
// and the background widget is dark
return Scaffold(
body: CustomScrollView(
controller: _scrollController,
slivers: <Widget>[
SliverAppBar(
pinned: true,
leading: BackButton(
color: _changecolor? Colors.white: Colors.black, // Here
),
actions: <Widget>[
IconButton(
icon: Icon(
Icons.shopping_cart,
color: _changecolor? Colors.white: Colors.black, // Here
),
onPressed: () {},
),
],
expandedHeight: 200.0,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text(
'title',
style: TextStyle(
fontSize: 18.0,
color: _changecolor? Colors.white: Colors.black, // Here
),
),
// Not affecting the question.
background: widget.backgroundWidget,
),
),
// Not affecting the question.
SliverToBoxAdapter(child: widget.bodyWidgets),
],
),
);
}
}
answered 2 days ago
Saed Nabil
945
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 2 days ago
Saed Nabil
945
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 2 days ago
Saed Nabil
945
answered 2 days ago
Saed Nabil
945
945
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Saed Nabil is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
up vote
0
down vote
You can use LayoutBuilder to get sliver AppBar biggest height. When biggest.height = 80.0, it actually means sliver appbar is collapsed.
Here is a full example:
import 'package:flutter/material.dart';
void main() => runApp(MaterialApp(
home: MyApp(),
));
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
var top = 0.0;
@override
Widget build(BuildContext context) {
return Scaffold(
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return <Widget>[
SliverAppBar(
expandedHeight: 200.0,
floating: false,
pinned: true,
flexibleSpace: LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
// print('constraints=' + constraints.toString());
top = constraints.biggest.height;
return FlexibleSpaceBar(
centerTitle: true,
title: AnimatedOpacity(
duration: Duration(milliseconds: 300),
//opacity: top == 80.0 ? 1.0 : 0.0,
opacity: 1.0,
child: Text(
top.toString(),
style: TextStyle(fontSize: 12.0),
)),
background: Image.network(
"https://images.unsplash.com/photo-1542601098-3adb3baeb1ec?ixlib=rb-0.3.5&ixid=eyJhcHBfaWQiOjEyMDd9&s=5bb9a9747954cdd6eabe54e3688a407e&auto=format&fit=crop&w=500&q=60",
fit: BoxFit.cover,
));
})),
];
},body: ListView.builder(
itemCount: 100,
itemBuilder: (context,index){
return Text("List Item: " + index.toString());
},
),
));
}
}
Final result:
answered 2 days ago
Jack Sun
356
add a comment |
up vote
0
down vote
You can use LayoutBuilder to get sliver AppBar biggest height. When biggest.height = 80.0, it actually means sliver appbar is collapsed.
Here is a full example:
import 'package:flutter/material.dart';
void main() => runApp(MaterialApp(
home: MyApp(),
));
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
var top = 0.0;
@override
Widget build(BuildContext context) {
return Scaffold(
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return <Widget>[
SliverAppBar(
expandedHeight: 200.0,
floating: false,
pinned: true,
flexibleSpace: LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
// print('constraints=' + constraints.toString());
top = constraints.biggest.height;
return FlexibleSpaceBar(
centerTitle: true,
title: AnimatedOpacity(
duration: Duration(milliseconds: 300),
//opacity: top == 80.0 ? 1.0 : 0.0,
opacity: 1.0,
child: Text(
top.toString(),
style: TextStyle(fontSize: 12.0),
)),
background: Image.network(
"https://images.unsplash.com/photo-1542601098-3adb3baeb1ec?ixlib=rb-0.3.5&ixid=eyJhcHBfaWQiOjEyMDd9&s=5bb9a9747954cdd6eabe54e3688a407e&auto=format&fit=crop&w=500&q=60",
fit: BoxFit.cover,
));
})),
];
},body: ListView.builder(
itemCount: 100,
itemBuilder: (context,index){
return Text("List Item: " + index.toString());
},
),
));
}
}
Final result:
answered 2 days ago
Jack Sun
356
add a comment |
up vote
0
down vote
up vote
0
down vote
You can use LayoutBuilder to get sliver AppBar biggest height. When biggest.height = 80.0, it actually means sliver appbar is collapsed.
Here is a full example:
import 'package:flutter/material.dart';
void main() => runApp(MaterialApp(
home: MyApp(),
));
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
var top = 0.0;
@override
Widget build(BuildContext context) {
return Scaffold(
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return <Widget>[
SliverAppBar(
expandedHeight: 200.0,
floating: false,
pinned: true,
flexibleSpace: LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
// print('constraints=' + constraints.toString());
top = constraints.biggest.height;
return FlexibleSpaceBar(
centerTitle: true,
title: AnimatedOpacity(
duration: Duration(milliseconds: 300),
//opacity: top == 80.0 ? 1.0 : 0.0,
opacity: 1.0,
child: Text(
top.toString(),
style: TextStyle(fontSize: 12.0),
)),
background: Image.network(
"https://images.unsplash.com/photo-1542601098-3adb3baeb1ec?ixlib=rb-0.3.5&ixid=eyJhcHBfaWQiOjEyMDd9&s=5bb9a9747954cdd6eabe54e3688a407e&auto=format&fit=crop&w=500&q=60",
fit: BoxFit.cover,
));
})),
];
},body: ListView.builder(
itemCount: 100,
itemBuilder: (context,index){
return Text("List Item: " + index.toString());
},
),
));
}
}
Final result:
answered 2 days ago
Jack Sun
356
You can use LayoutBuilder to get sliver AppBar biggest height. When biggest.height = 80.0, it actually means sliver appbar is collapsed.
Here is a full example:
import 'package:flutter/material.dart';
void main() => runApp(MaterialApp(
home: MyApp(),
));
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
var top = 0.0;
@override
Widget build(BuildContext context) {
return Scaffold(
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return <Widget>[
SliverAppBar(
expandedHeight: 200.0,
floating: false,
pinned: true,
flexibleSpace: LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
// print('constraints=' + constraints.toString());
top = constraints.biggest.height;
return FlexibleSpaceBar(
centerTitle: true,
title: AnimatedOpacity(
duration: Duration(milliseconds: 300),
//opacity: top == 80.0 ? 1.0 : 0.0,
opacity: 1.0,
child: Text(
top.toString(),
style: TextStyle(fontSize: 12.0),
)),
background: Image.network(
"https://images.unsplash.com/photo-1542601098-3adb3baeb1ec?ixlib=rb-0.3.5&ixid=eyJhcHBfaWQiOjEyMDd9&s=5bb9a9747954cdd6eabe54e3688a407e&auto=format&fit=crop&w=500&q=60",
fit: BoxFit.cover,
));
})),
];
},body: ListView.builder(
itemCount: 100,
itemBuilder: (context,index){
return Text("List Item: " + index.toString());
},
),
));
}
}
Final result:
answered 2 days ago
Jack Sun
356
answered 2 days ago
Jack Sun
356
answered 2 days ago
Jack Sun
356
answered 2 days ago
Jack Sun
356
356
add a comment |
add a comment |
Sina Seirafi is a new contributor. Be nice, and check out our Code of Conduct.
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Sina Seirafi is a new contributor. Be nice, and check out our Code of Conduct.
Sina Seirafi is a new contributor. Be nice, and check out our Code of Conduct.
Sina Seirafi is a new contributor. Be nice, and check out our Code of Conduct.
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Please Add Your Code also !
– anmol.majhail
2 days ago
@anmol.majhail Thanks for the heads up.
– Sina Seirafi
2 days ago
stackoverflow.com/a/51927031/10269042
– anmol.majhail
2 days ago