My Flutter Project structure is like this
Main() //Run App with MaterialApp and Routes
L HomePage() //Default route (/), with BottomNavigation
L MoviesPage() //Default BottomNavigation Index and shows a list of movies form TMDB
L DetailsMoviesPage()
L SeriesPage()
L DetailsSeriesPage()
L SupportPage()
L DetailsSupporPage()
The data update was stopped when Navigator between the tab, but when Navigator from MoviesPage() to DetailsMoviesPage() Or Navigator from SeriesPage() to DetailsSeriesPage() Or Navigator From
SupportPage() to DetailsSupporPage() Is building HomePage() and All Activity are being updated
As well as when writing on the textfield located in being update HomePage()?
body: _childnav[_currentIndex],
bottomNavigationBar: BottomNavigationBar(
onTap: onTabPressed,
currentIndex: _currentIndex, //this property defines current active tab
items: [
BottomNavigationBarItem(
icon: Icon(Icons.movie), title: Text('Movies')),
BottomNavigationBarItem(icon: Icon(Icons.tv), title: Text('Series')),
BottomNavigationBarItem(icon: Icon(Icons.help), title: Text('Help'))
],
),
Related
What's the name of the Flutter widget that has icons below the screen and I can slide to right and left to change between these screens (Ex: Twitter main page)
I could create a Container with a Row and the Icons and do this manually, but I suspect that already exists this widget on Flutter.
this bottom navigation bar can be done using BottomNavigationBar in the bottomNavigationBar property on your Scaffold :
bottomNavigationBar: BottomNavigationBar(
items: [
BottomNavigationBarItem(icon: Icon(Icons.home), label: 'Home'),
BottomNavigationBarItem(
icon: Icon(Icons.business), label: 'Business'),
BottomNavigationBarItem(icon: Icon(Icons.school), label: 'School'),
],
),
and for the slidable pages can be done using a PageView widget:
PageView(
children: <Widget>[
ScreenOne(),
ScreenTwo(),
ScreenThree(),
],
);
and you can link both of them when you click an item in the BottomNavigationBar, it will navigate to a specific page with a PageController.
I have a screen with a BottomNavigationBar and an IndexedStack that swaps the child view based on the bottom bar index.
Everything is ok, except that all four pages are created at once, loading their data that is quite heavy and slowing down the app for some seconds.
Is there a setup that allows me to load each page only when the corresponding tab gets tapped?
Condition1: You want to simply load all tabs under IndexStack() at once during start and preserve them.
Solution: Use 'const' in front of all tabs in IndexedStack() > children[].
Condition 2: You want to load only the Homepage and the rest of the pages on their respective index clicks.
Solution: In children[] under IndexdStack() provide ternary condition with option for empty containers for all tabs. Put ternary condition of currentIndex. In this case though, the respective tab will load each time you click on it.
Condition 3: You want to load only the Homepage and the rest of the pages on their respective index clicks and preserve them once loaded.
Solution:
Use the solution for condition 2
Set up a bool 'ex. pageLoaded'. One for each tab.
Call the bool in the IndexedStack() > OnTap. Make it true on respective index clicks.
Set up another ternary operation against the first ternary operation with 'const Tabname' as the alternative.
I would suggest to remove the IndexedStack and make the widgets List and render the data based on the index.
List<Widget> _pages = [Home(), Business(),School()];
Make the Provider/Bloc instance on your bottom navigation container widget
return MultiProvider(
providers [
Provider<Something>(create: (_) => Something()),
],
child :Scaffold(
appBar: AppBar(
title: const Text('BottomNavigationBar Sample'),
),
body: _pages[_selectedIndex],
bottomNavigationBar: BottomNavigationBar(
items: const <BottomNavigationBarItem>[
BottomNavigationBarItem(
icon: Icon(Icons.home),
label: 'Home',
),
BottomNavigationBarItem(
icon: Icon(Icons.business),
label: 'Business',
),
BottomNavigationBarItem(
icon: Icon(Icons.school),
label: 'School',
),
],
currentIndex: _selectedIndex,
selectedItemColor: Colors.amber[800],
onTap: _onItemTapped,
)
)
On each page bind the consumer of the provider, call the api in your provider
I have just started programming with Flutter and Dart
And I wanted to know how to set the code and content for a tab or button
For example, I put a button icon in the bottom navigator and what code and method is needed so that after clicking on that button, a new page will open one by one and the operation will be performed.
Thanks.
For bottom navigation bar you can use like this:
`
void _onItemTapped(int index) {
setState(() {
_selectedIndex = index;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('BottomNavigationBar Sample'),
),
body: Center(
child: _widgetOptions.elementAt(_selectedIndex),
),
bottomNavigationBar: BottomNavigationBar(
items: const <BottomNavigationBarItem>[
BottomNavigationBarItem(
icon: Icon(Icons.home),
label: 'Home',
backgroundColor: Colors.red,
),
BottomNavigationBarItem(
icon: Icon(Icons.business),
label: 'Business',
backgroundColor: Colors.green,
),
BottomNavigationBarItem(
icon: Icon(Icons.school),
label: 'School',
backgroundColor: Colors.purple,
),
BottomNavigationBarItem(
icon: Icon(Icons.settings),
label: 'Settings',
backgroundColor: Colors.pink,
),
],
currentIndex: _selectedIndex,
selectedItemColor: Colors.amber[800],
onTap: _onItemTapped,
),
);
}
}
`
You need to set onTap() for actions when you press the button and setState() to update the state of the widget.
All buttons (TextButton, ElevatedButton ect) will be having onTap() property, you can call a method inside onTap().
For more details visit this: https://flutter.dev/docs/development/ui/widgets/material#Buttons
This is a very specific use case and has a different solution to what you would usually do with buttons.
The documentation for the BottomNavigationBar() shows a few code examples. You can copy paste that and modify it to suit your need. What they basically do is add BottomNavigationBar() items and add an onChanged/onTap method which you would use to change the page.
For buttons in general, they would have an onPressed parameter where you can pass a function or an anonymous function (e.g. () {your code here}). Flutter provides you with a few default buttons such as ElevatedButton() and TextButton() which you can read more about here (https://api.flutter.dev/flutter/material/ElevatedButton-class.html) and here (https://api.flutter.dev/flutter/material/TextButton-class.html). They have parameters which allow you to tweak them. This is where you can run functions when they are pressed.
If you want to make a non-button widget clickable you can use a GestureDetector() which you can read more about here (https://api.flutter.dev/flutter/widgets/GestureDetector-class.html). It is also has an onTap similar to the buttons but also has much more options such as long, double, triple, etc. taps as well as gestures like swipes.
It all comes down to getting used to all those different widgets and you will get familiar with them through practice.
bottomNavigationBar: new BottomNavigationBar(items: [
new BottomNavigationBarItem(icon: new Icon(Icons.account_balance))]),
When I run, I get this error
As the error suggested it needs 2 or more items in bottom navigation bar. The idea is, if you have a navigation bar you should have multiple items to navigate. If you want only one item don't use BottomNavigationBar
You need to have at least 2 children for your items like:
bottomNavigationBar: BottomNavigationBar(
items: [
BottomNavigationBarItem(
icon: Icon(Icons.account_balance),
),
BottomNavigationBarItem(
icon: Icon(Icons.account_circle),
),
],
)
HomeScreen() function call the Home screen of App.
How I Can route/move to "Team", "Add", etcetera page without BottomNavigationBar and AppBar.
I want show another page and back button, with new Bottom Navigation Bar.
I have this on my Flutter Project:
class APPMain extends StatefulWidget {
#override
_APPMainState createState() => _APPMainState();
}
class _APPMainState extends State<APPMain> {
int _currentIndex = 0;
_onTapped(int index) {
setState(() {
_currentIndex = index;
});
}
#override
Widget build(BuildContext context) {
List<Widget> screens = [
HomeScreen(),
Center(child: Text("Team")),
Center(child: Text("Add")),
Center(child: Text("Search")),
Center(child: Text("Settings")),
];
return Scaffold(
appBar: AppBar(
backgroundColor: Color(0xffffffff),
iconTheme: IconThemeData(color: Colors.grey),
title: Text("Test App", style: TextStyle(color: Colors.grey),),
actions: <Widget>[
IconButton(
icon: Icon(Icons.account_circle),
onPressed: (){},
),
],
),
body: Container(
color: Color(0xfff4f4f4),
child: Center(
child: screens[_currentIndex],
),
),
bottomNavigationBar: BottomNavigationBar(
currentIndex: _currentIndex,
type: BottomNavigationBarType.fixed,
fixedColor: Colors.red,
onTap: _onTapped,
items: [
BottomNavigationBarItem(
title: Text('Home'), icon: Icon(Icons.home)),
BottomNavigationBarItem(
title: Text('Team'), icon: Icon(Icons.group)),
BottomNavigationBarItem(
title: Text('Add'), icon: Icon(Icons.add)),
BottomNavigationBarItem(
title: Text('Search'), icon: Icon(Icons.search)),
BottomNavigationBarItem(
title: Text('Settings'), icon: Icon(Icons.settings)),
]),
);
}
}
Thank you so much for help.
This is almost certainly a duplicate but I wasn't able to find a question asking something similar with a quick search so I'll answer anyways.
The answer is actually quite simple, but requires understanding a bit more about how to write flutter applications - you should be using a Navigator or the navigator built right into MaterialApp or WidgetApp rather than making your own navigation. The simplest way is to use MaterialApp's routes property and pass in a map with each of your pages. Then when you want to switch pages, you simply use Navigator.pushNamed(context, <name>) from wherever you want to switch the page (i.e. a button).
The part that can be slightly confusing when you come from other frameworks is that rather than having one Scaffold and switching the body of it, the entire page should switch and each page should have a Scaffold.
Here's an example in the documentation showing how to navigate between pages.
For the record, although it's a bad idea you could make it work with your original code as well - all you'd have to do is build a different BottomNavigationBar with different options depending on what _currentIndex is set to. But I don't recommend that. With what I've suggested you also get animations between pages, back button functionality, you can hook up analytics to track page usage, and a bunch more things that flutter provides as part of navigation.