I have two listview screen on my app. User can navigate between them using BottomNavigationBar control.
On listview.builder function, I return something like this
return ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (context, index) {
return ListTile(
title: Text('...'),
subtitle: Text('...'),
onTap: () {
...
}
)
});
I found onTap handler seems mixed between those 2 listviews.
When I open first list view, flutter serve the correct onTap,but when I switch to second listview, flutter still serving the first listview onTap.
Seems the onTap is cached by flutter (title & subtitle seems okay). Any idea?
Sample source code: https://github.com/jazarja/flutter_app
The problem is in your compararing transition values. Because you are first reversing the animation transition of current view.
In your botton_nav.dart, change this:
return aValue.compareTo(bValue);
to this:
return bValue.compareTo(aValue);
Yes the problem is that the animations haven't completed by the time the comparison is being done so the widget at the top of the stack is always 1 tab selection behind. You actually don't need to build a stack at all, just replace Center(child: _buildTransitionStack()) here with _navigationViews[_currentIndex].transition(_type, context) and it should work.
Related
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Can I get a logic/code for highlighting just the selected value from this list view which is inside a container and it is scrollable also that the axis is set to Horizontal.
I have used a list view builder to align the same and also generated the list of numbers.
Please check the sample image of the widget attached.
Blockquote
]1
It's hard to tell you exactly how to do it without any code examples, and I'm also not sure what you mean by selected. Is that already decided before building the list, or is it decided when the user selects from the list?
If it is already decided, you can pass a value from the parent component that tells the list to highlight a certain value.
If a user is selecting the value to highlight, you can use a combination of setState and onTap with GestureDetector. Here's a potential rough skeleton:
int selectedIndex?;
ListView.builder(
itemCount: litems.length,
itemBuilder: (BuildContext ctx, int index) {
return GestureDetector(
onTap: () {
setState(() {
selectedIndex = index;
});
},
child: Container(
backgroundColor: selectedIndex == index ? highlightedColor : undefined;
child: {{child content}}
),
);
}
)
Android Studio + Flutter
I have a Row at the bottom of the screen.
It includes TextField and Button (Add).
When there is some text in TextField and user clicks Add, I want it to appear as a Bubble inside a Container starting from the top left.
What would be the correct way to do it? I want the bubbles to accumulate like a notes app and eventually be scrollable too.
Thanks!
Try using the Snackbar Widget, which can be personalized heavily.
Here's the documentation.
EDIT. Since you want a permanent list of bubbles on the top, I'd suggest using a provider, so that when you click the button, the onTap event validates and adds the data to a list (below, myElements). Then, up to the top, just add a Consumer Widget that listens to changes to the list (it rebuilds its children every time something changes). In the following example code (I have not tested it!) I use an Expanded widget just for fun and I use a ListView.builder inside the Consumer to show the list of elements you've added, since the amount of added element could be high. Finally, I suggest using either ListTile or Card or a combination of the two, since you want something aesthetically beatiful like a bubble (you'll have to play with the settings, a little):
return ... (
child: Column(
children: [
Text("Some title..?"),
Expanded(
Consumer(
builder: (ctx, myElements, _) => ListView.builder(
itemCount: myElements.length,
itemBuilder: (ctx, i) => ListTile(
title: Text("You added ${myElements[i]}"),
// something else...?
),
),
),
),
Row( /* ... Text field + Button here... */),
],
),
// ...
Dears,
it could be just a mistake of mine but ...it's driving me crazy ;)
I have a ListView inside my statefulwidget:
Expanded(
child: ListView.builder(
padding: EdgeInsets.all(10.0),
itemCount: searchableFoodList.length,
itemBuilder: (BuildContext context, int index) {
print('4 - SFL - ${searchableFoodList[index].id} - ${searchableFoodList[index].name}');
return
FoodItem(
id: searchableFoodList[index].id,
baseUnit: searchableFoodList[index].baseUnit,
baseUnitS: searchableFoodList[index].baseUnitS,
baseVal: searchableFoodList[index].baseVal,
baseValCal: searchableFoodList[index].baseValCal,
mediumVal: searchableFoodList[index].mediumVal,
mediumValCal: searchableFoodList[index].mediumValCal,
name: searchableFoodList[index].name,
note: searchableFoodList[index].note
);
},
),
searchableFoodList is modified (according user selection) inside a setState().
Let say that we have a 3 FoodItem(s), so my searchableFoodList is [FoodItem-1, FoodItem-2, FoodItem-3] and everything is working fine.
If I select a single item in my list, let say "FoodItem-2", the searchableFoodList becomes [FoodItem-2] and the list displayed contains (correctly) just one item but it is FoodItem-1.
Note that I inserted a print ...and it prints "FoodItem-2"
I guess that the problem is that it is considered the "original list" and it is changed only the length of the list but the list itself is not re-generated.
I have no more ideas ...any suggestions to solve this problem?
P.S.
FoodItem is stateful widget as well (an animated one). I did something similar with using stateless widget and I didn't have any problem
I have this listview.builder which is supposed to show some orders from an array of Order objects based on their status.
It looks kinda like this:
The List works just fine until, for some reason, when I scroll down and the viewport can only display the order with index (the one in the listview builder function) 5 and then press another category like "New", setState() is called and the whole thing rebuilds, but the builder's index starts at 5 and the listview.builder doesn't build anything from 0 - 4. I've printed the index in the builder and caught this bug, but I still don't understand why this is happening.
This is what my listview.builder code looks like:
ListView.builder(
controller: _scrollController,
shrinkWrap: true,
itemBuilder: (BuildContext context, int index) {
print("INDEX: $index");
return _showOrder(index);
},
itemCount: orders.length,
),
This is the code for _showOrder():
Widget _showOrder(int i) {
String _currOrderStatus = orders[i].orderStatus;
/// _selectedOrderStatus is just a String which changes depending on the selected category of orders.
/// e.g. "New" or "Past"
return _currOrderStatus == _selectedOrderStatus
? ShowMyOrderWidget()
: SizedBox(
/// AND FOR SOME REALLY WEIRD REASON, THIS FIXES THE PROBLEM
/// It works with any height, as long as it's not 0, but if I have a lot of them, then the
/// layout gets spaced out and messy. With such a low number, this is highly unlikely, but
/// still seems like a stupid fix.
/// Why does this work? Why is this happening? Is there a better way to fix it?
height: 0.000000001,
);
}
And I just call setState() in the onPressed() function of those buttons on top of the screen.
Changing the items inside the ListView doesn't reset scroll position.
Since you're already assigning a ScrollController to your ListView, try calling "jumpTo(0.0)" to reset it's scroll position before calling setState().
_scrollController.jumpTo(0.0);
My question is about flutter's listview.
When I delete item from a list and set the state
setState(() {
items.removeAt(500);
});
flutter listview.builder scrolls to the top. I want it not to scroll after deleting item from the list.
What's your suggestion?
Thanks in advance.
our widget tree is simple we creating list like
ListView.builder(
itemCount: messages.lenght,
itemBuilder: (ctx,index){
return GestureDetector(
onTap: (){
showModalBottomSheet()...
}
);
}
)
on bottom sheet there is a function calls setState() and delete item then ListView scrolls to top