hide the bottom navigation bar if cart is empty flutter - flutter

I am adding the products to cart and displaying the total amount in the bottom navigation bar ,if the cart is empty i want to show another screen in the same page i.e
and if cart is not empty i want to show
body: _getitemCon.get_cart_item == null
?
Center(
child:_canShowButton?emptycart(): SizedBox(),
)
: new ListView(),
bottomNavigationBar: Container()
this is how i tried to show the screens in same page

You could wrap the bottomNavigationBar with Visibility widget, like this:
bottomNavigationBar: Visibility(visible: condition, child: Container())
Then, the condition to show the bottomNavigationBar in your case seems to be _getitemCon.get_cart_item != null. Just make sure to call setState when you update the condition.

Related

How Do I Create this Page Swipe Behaviour in Flutter?

I want to implement this page swipe behaviour in Flutter as shown in the picture. The user should be able to drag the screen from the right edge of the screen to the left up until the page is dragged halfway through the screen. Once released, the app will move onto a new page.
Desired Outcome
You can use Slidable Package and wrap the whole page in a slideable.
Slidable(
key:UniqueyKey(),
endActionPane: ActionPane(
onDismissed: (){}, // Leave empty, confirmDismiss will handle event
confirmDismiss: () asnyc {
// function that rerender page with next question
}
children: [] //list of widgets to show when slide
child: // this is the widget that shows and will be slideable
if you want to have both sides you just add startActionPane aswell.

How can i make shared appBar and bottomNavigation across flutter screens

i am new to flutter and i would like to have a shared appBar and bottomNavigationBar
the way i am currently using is implementing them in spearte files and importing them in each screen but i need to make one screen contains the appbar and the bottomNavigationBar and the content of the body renders diffrent views according to the routes and i can't make it at main page because the main page renders welcome screen
in reactJS i was importing the header and footer and make my routes between them how can i make somthing similar in flutter
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: navBar(),
body: SingleChildScrollView(reverse: true, child: ScanPassport()),
bottomNavigationBar: bottomNavigation(),
currentIndex: _selectedIndex,
onTap: _onItemTapped,
showSelectedLabels: false,
showUnselectedLabels: false,
type: BottomNavigationBarType.fixed,
),
);
}
}
A couple of options:
Use MaterialApp() router. There's a tutorial here showing how to refactor your Scaffold() so you don't have duplicate code for appBar, bottomNavigationBar, etc. This is the official Flutter method for view routing.
If you need to swap out your Scaffold() body but can't change your other Scaffold() elements, you can create a widget for the body that takes a "page" value and change what it returns from build() based on the "page" value passed. The widget holding your Scaffold can be stateful and your bottom navigation bar can setState() the page number.
In your context, You can just have a single scaffold homepage screen after logged in success or after welcome screen (depends up app). Once you navigate to homepage, You will have appBar and bottom navigation bar at top and bottom respectively. The remaining portion at center will be your body content of the selected tab. Once you switched the tap on bottom navigation, you should change the content rather than using routes for switching the body content. The current page status will be preserved on homepage.

flutter constant appbar on different screen navigation

I am developing an app in flutter with few screen I want to add AppBar in home screen and want that appbar to be fixed in all screen, but in the dummy code which i have written the complete screen is getting replaced by that.
Below is the screen
HomeScreen - here i have created appbar
When I click on AddPolicy Button, i get that screen where right now i just have a text but the complete screen gets replaced as below, but I want the header appBar should be fixed. How can I achieve this.
Below is the code
homepage - https://github.com/lodha13/samkit/blob/main/lib/screens/home.dart
AddPolicy page - https://github.com/lodha13/samkit/blob/main/lib/screens/add_policy.dart
You have two opptions:
have a global widget for appbar and use it on each different page,
or
You can have one Scaffold in your main.dart and instead of generating a new one for each page, only change the body parameter using setState. for example:
// have as many widget as you want for each page
const body1 = Text("body1"); //just a simple example, you can change it to whatever you want.
const body2 = Text("body2");
return Scaffold(
appBar: AppBar(
title: const Text('Sample Code'),
),
body: handleBody(selectedIndex)
);
then you can have a function to handle bodies:
handleBody(int index){ // you can pass different input for body selection I have used an int for simplicity
if(index == 1){return body1;}
if(index ==2) {return body2;}
// and so on
}
now with changing the selectedIndex you can show different bodies. Personally, I prefer to have a list of widgets and select one of them based on selectedIndex.

SliverList setState to Affect Only Selected Item Flutter

I have a button on every item on my SliverList. When I click a specific list item button, I wish it change to a different widget by using setState. Only that specific item button should change to a different widget while the rest on the list retains its own item button.
Example below. The problem of course is that when I click any button on the list, all buttons on every item on the list changes. What is needed so that it affects only the specific item on the list whose button was pressed?
SliverList(
delegate: SliverChildBuilderDelegate((BuildContext context, int index) {
final item = gd[index];
return Container(
child: Column(
children: [
item.mypicwidget(context,item.pid),
_shownewwidget
? item.newwidget(context)
: RaisedButton(
onPressed: () {
setState(() {
_shownewwidget=true;
});
},
child: const Text('Press Me'),
),
]
),
);
Figured this out.
I believe the approach is to add to the existing list an object key to represent whether widget1 or widget2 to render, eg. tag: 'normal' or tag: 'clicked'. Depending on index.tag, either widget1 or widget2 will be displayed. So for a widget with a button wherein the tag is normal, the button will have a function when clicked changes the index.tag of the item from normal to clicked. When the Sliverlist sees this new value, it automatically renders the corresponding widget.

Flutter floating button hide and show on whether ListView index

I have an app that has a ListView and Floating Button. I wanted to hide the Floating Button if Index 0 in the ListView is shown and show the Floating Button when Index 0 is not shown in the ListView. Most of the information in the web (including Stackoverflow) covers hiding the button when scrolling (direction) and not based on the index shown by ListView.
you can checklist null or not. I just add a demo code.
List<String> demoList = new List<>();
floatingActionButton: demoList != null ?
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.navigation),
backgroundColor: Colors.green,
)
:Text(''),
);
if the list has a value then it shows a floating button.
Use Visibility widget around FloatingActionButton. When the item shows, just call setState() method with visibility value.