Widget _buildImageColumn() => Container(
decoration: BoxDecoration(
color: Colors.black26,
),
child: Column(
children: [
_buildImageRow(1),
_buildImageRow(3),
],
),
);
Widget _buildDecoratedImage(int imageIndex) => Expanded(
child: Container(
decoration: BoxDecoration(
border: Border.all(width: 10, color: Colors.black38),
borderRadius: const BorderRadius.all(const Radius.circular(8)),
),
margin: const EdgeInsets.all(4),
child: Image.asset('images/pic$imageIndex.jpg'),
),
);
Widget _buildImageRow(int imageIndex) => Row(
children: [
_buildDecoratedImage(imageIndex),
_buildDecoratedImage(imageIndex + 1),
],
);
The above code is taken from flutter website.
I want to change the background color of the widget with some animation (image). But after first tab, i don't want to execute the tap function again.
I tried to move _buildDecoratedImage to a statefulwidget and i can animate the particular widget and disable tap on that widget only. I am not able to disable tap on other three images (widgets).
though i can animate the background without moving _buildDecoratedImage to a statefulwidget and disable the tap of all the widget. But the entire screen is rebuilt.
Is there any way to achieve this without using streams?
One of the image must be tapped and animate the background and every image should not be tapped after that.
Please suggest the best solution for this.
If you don't want to use bloc plugin, you may want to consider using Stream to listen for changes in values set.
final _imageIndex = StreamController<int>.broadcast();
Stream<int> get imageIndex => _imageIndex.stream;
// Update image index
updateImageIndex(int index) {
_imageIndex.sink.add(index);
}
Then to update, you can call updateImageIndex(index). To listen for changes, you can set imageIndex on a StreamBuilder - this gets rebuilt when changes on Stream is detected.
StreamBuilder<int>(
stream: imageIndex,
builder: (context, AsyncSnapshot<int> snapshot) {
if (snapshot.hasData) {
debugPrint('Image index: ${snapshot.data}');
}
}
)
Related
I have a Flutter Web application where I need to show a widget on the right side of a ListView when I click an item and this widget should always be visible on screen. I can achieve my objective puting both on a Row and using a scrollable only for the ListView, but that requires the ListView to be wrapped by a widget with defined height.
Defining a container with height to wrap the ListView breaks the responsiveness when I resize the browser, as the container doesn't fit the height of the screen.
I thought of using the shrinkWrap property of the ListView so I don't have to wrap it in a widget with predefined height, but that makes the whole Row scrollable vertically, eventually causing the widget to leave the viewport.
I would appreciate if somebody knows how could I keep this right side widget fixed on screen so I can achieve my objective without losing responsiveness.
Here's something similitar to what I've got so far:
class PageLayout extends StatefulWidget {
const PageLayout({Key? key, required this.items}) : super(key: key);
final List<String> items;
#override
State<PageLayout> createState() => _PageLayoutState();
}
class _PageLayoutState extends State<PageLayout> {
final rightSideWidget = Container(
decoration: BoxDecoration(
color: Colors.red,
border: Border.all(color: Colors.white, width: 2),
),
height: 200);
#override
Widget build(BuildContext context) {
return Scaffold(
body: SingleChildScrollView(
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.start,
children: [
SizedBox(
width: MediaQuery.of(context).size.width * 0.49,
child: ListView.builder(
shrinkWrap: true,
itemBuilder: (context, index) => Container(
decoration: BoxDecoration(
color: Colors.blue,
border: Border.all(color: Colors.white, width: 2),
),
height: 200,
child: Center(
child: Text(
widget.items[index],
style: const TextStyle(color: Colors.white),
),
),
),
itemCount: widget.items.length,
),
),
Expanded(child: rightSideWidget),
],
),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
I want rightSideWidget to be always centered on screen or follow the scroll.
You can divide your screen into two sections, right section and left section; thereby being able to control behaviour of widgets in both sections.
Divide the overall screen into 2 proportional sections using a Row
widget
Put this Row widget inside a Container with height equal to screen height for preserving responsiveness | Use MediaQuery to get current height of page
Now left hand section can individually scroll, and on click of any option from this section you can define behaviour for right section; while keeping the left section constant throughout page lifecycle
I have a list of image paths and I am using the List.generate method to display images and a cross icon to remove image from list. Upload method is called on each image and when I remove the image from the list the method still keeps running until the image is uploaded. The behavior I am expecting is when I remove the image from the list the method should also stop running. I am using a future builder to display the circular progress bar and error icons while uploading an image.
What should I be doing to make sure the future method associated to the current widget also stops when I remove the widget from the list?
This is the code where I am creating a list
List.generate(
files.length,
(index) {
var image = files[index];
return Container(
height: itemSize,
width: itemSize,
child: Stack(
children: <Widget>[
Container(
getImagePreview(image, itemSize)
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: [
uploadHandler(image, field),
InkWell(
onTap: () => removeFileAtIndex(index, field),
child: Container(
margin: EdgeInsets.all(3),
decoration: BoxDecoration(
color: Colors.grey.withOpacity(.7),
shape: BoxShape.circle,
),
alignment: Alignment.center,
height: 22,
width: 22,
child: Icon(Icons.close, size: 18, color: Colors.white),
),
),
],
),
],
),
);
},
)
This is Upload Handler method.
Widget uploadHandler(file, field) {
return FutureBuilder(
future: upload(file),
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
if (snapshot.data.statusCode == 201) {
return doneUpload();
} else {
logger.d(snapshot.error);
return error();
}
} else {
return uploading();
}
},
);
}
The lifecycle of the widget isn't attached to the async functions invoked by the widget.
You can check the mounted variable to check if the widget still mounted from your async function.
I wanted to have a carousel with 5 photos and when I press any of the images I want to navigate to a different screen. I watched many videos but couldn't find any solutions. I used carousel_slider package.
CarouselSlider(
CarouselOptions(height: 400.0),
items: [1,2,3,4,5].map((i) {
return Builder(
builder: (BuildContext context) {
return Container(
width: MediaQuery.of(context).size.width,
margin: EdgeInsets.symmetric(horizontal: 5.0),
decoration: BoxDecoration(
color: Colors.amber
),
child: Text('text $i', style: TextStyle(fontSize: 16.0),)
);
},
);
}).toList(),
)
Imagine I have 5 different pages and when I press any of the pictures in the carousel then I should be navigated to a particular page. If I use a Gesture detector how can I navigate him using navigator.push?
Try using ManuallyControlledSlider from
https://github.com/serenader2014/flutter_carousel_slider/blob/master/example/lib/main.dart but change onPressed callback inside
Iterable -> RaisedButton to navigate on specific page.
I am building this card game app which has a list of Cards (containers with special effects) and the list is managed and updated by the Provider/Consumer mechanism.
It looks like this
class LowerSectionWithScrollingCardList extends StatefulWidget {
#override
_LowerSectionWithScrollingCardListState createState() =>
_LowerSectionWithScrollingCardListState();
}
class _LowerSectionWithScrollingCardListState
extends State<LowerSectionWithScrollingCardList> {
#override
Widget build(BuildContext context) {
return Consumer<GameState>(builder: (context, gameState, child) {
print('lower list ${gameState.gcurrentPlayers[0].ownList}');
return Expanded(
flex: 34,
child: Container(
color: Colors.white,
child: ListView(
children: gameState.gcurrentPlayers[0].ownList,
scrollDirection: Axis.horizontal,
),
),
);
});
}
}
gameState.gcurrentPlayers[0].ownList is the first player which is us, and ownlist is the actual list of widgets or cards which gets updated by clicking some other buttons in the app.
the list is updated by this method exactly
void ggiveCardToCurrentPlayer(int howMuch){
for(int i=0;i<howMuch;i++)
ggetPlayerWithCurrentTurn().ownList.add(gplayingCards.removeLast());
notifyListeners();
}
Now after the "notifylisteners" is called, I am 100% sure that the Consumer is updated with the new data, because the print statement in the build method prints the newly added cards.
Finally, the issue is that the listView itself doesn't update while the list it renders has those added cards.
I checked out a few posts regarding a similar issue and they suggest that one add keys to the Data items, in my case the data items are my cards, and I added keys to them. No change.
class RegularUnoCard extends StatelessWidget{
final Color _color;
final String _value;
final Key _key;
RegularUnoCard(this._color, this._value,this._key);
#override
Widget build(BuildContext context) {
return Container(
key: _key,
margin: EdgeInsets.symmetric(
vertical: _cardMarginVer, horizontal: _cardMarginHor),
padding: EdgeInsets.all(15),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(_cardCornerRadii),
border: Border.all(color: _color, width: 4, style: BorderStyle.solid),
boxShadow: [
BoxShadow(
color: _color,
spreadRadius: (_value == plus2) ? 8 : 2,
blurRadius: 5)
],
color: Colors.white,
),
child: Container(
height: _cardHeight,
width: _cardWidth,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(60),
color: _color,
),
child: Center(
child: getLogo(),
),
),
);
}
I hope this the correct way of putting keys in the Cards.
I also read that one must call setState() but I dont have any place to call Setstate from within my listView.
I have tried replacing the ownList logic with Provider.of(context).playerlist[0].ownlist etc etc but that too doesnt work
I hope I have supplied enough data for this evaluation. Please comment if more information is required. Thanks a lot for your time and suggestions.
I read more about the problem, the source which was helpful was this
Basically my list was being updated but I was providing the reference of the array, and since flutter works on immutable data, it did not detect my array change. So all I had to do was to build a new list from the existing reference array.
children: List<Widget>.from(gameState.gcurrentPlayers[0].ownList),
The final ListView should look like
#override
Widget build(BuildContext context) {
return Consumer<GameState>(builder: (context, gameState, child) {
print('lower list ${gameState.gcurrentPlayers[0].ownList}');
return Expanded(
flex: 34,
child: Container(
color: Colors.white,
child:ListView(
children: List<Widget>.from(gameState.gcurrentPlayers[0].ownList),
scrollDirection: Axis.horizontal,
),
),
);
},key: UniqueKey(),);
}
}
Now my card game is updating with the new cards!!
I am building an app in Flutter,that supposed to be a social network app-similar to faceboook.
I have implemented a like button-when pressed is sending the server the request,and then depending on the status code it sets the state.My problem begins when the setState() is rendering again the avatar picture,or creating it again from scratch(the avatar is stored in a 64base String).
the likePress is a future that sends the request and then sets the boolean isLiked accordingly.
this is the creating of the like button:
buildLikeButton(int ownerId, int postId) {
return RepaintBoundary(
child: FutureBuilder<bool>(
future: getLike(ownerId, postId),
builder: (BuildContext context, AsyncSnapshot<bool> snapshot) {
IconButton likeButton;
if (snapshot.hasData) {
isLiked = snapshot.data;
likeButton = createLikeButton(ownerId, postId);
} else if (snapshot.hasError) {
isLiked = false;
likeButton = createLikeButton(ownerId, postId);
print('the snapshot has an error ${snapshot.error}');
} else {
isLiked = false;
likeButton = createLikeButton(ownerId, postId);
}
return likeButton;
}));
}
createLikeButton(int ownerId, int postId) {
return IconButton(
icon: returnLikeIcon(isLiked),
color: Theme.of(context).accentColor,
onPressed: () async {
if (this.mounted) {
setState(() {
Future lol = likePress(ownerId, postId).then((onValue) {});
});
}
},
);
}
and this is the creation of the avatar:
createAvatar(BuildContext context, avatar_base64, int ownerId) {
Uint8List bytes = base64Decode(avatar_base64.split(',').last);
return RepaintBoundary(
child: CircleAvatar(
radius: 25.0,
backgroundImage: MemoryImage(bytes),
backgroundColor: Colors.transparent,
));
}
The widget that displays them together is the Post widget which i have created for this project,and this is it's build function:
Widget build(BuildContext context) {
return InkWell(
borderRadius: BorderRadius.circular(0.2),
child: Container(
decoration: BoxDecoration(boxShadow: [
BoxShadow(
color: Theme.of(context).primaryColor,
blurRadius: 1.0,
spreadRadius: 1.0, // has the effect of extending the shadow
offset: Offset(
5.0, // horizontal, move right 10
5.0, // vertical, move down 10
),
),
]),
child: Card(
elevation: 10.0,
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Flexible(
fit: FlexFit.loose,
child: postInfo(context, time, ownerId)),
Divider(
thickness: 1.0,
height: 10.0,
indent: 10.0,
endIndent: 10.0,
),
postContent(content),
Divider(
thickness: 1.0,
height: 10.0,
indent: 10.0,
endIndent: 10.0,
),
createButtonBar(ownerId, postId),
],
)),
));
}
postInfo is just a FutureBuilder that builds the ListTile that adds up the avatar and the name, and createButtonBar creates the like button and 2 more buttons.
I would like to change the icon when the user presses the like button,but only if the server has responded with the right status code and without rendering and creating the whole Post widget over again.Thank you for the trouble!
This means that the avatar is beneath the point where you are calling setState(() {}). In your case, the method is probably inside that particular widget and the widget is being rebuilt.
I suggest for you to solve the problem to move the creation of the avatar above. In this way, if you need to rebuild the object the avatar will not be created anew but simply placed within the new widget. Place some debugPrints around to speed up the process and try to refactor the code to see if you missed something.
After taking a better look at my code,I decided to create a different Widget for each part of the post,so I can initialize everything that will not be built again outside of the build method.
so if you want to exclude a widget from the setState() method, you need to move it outside the current widget(by creating a widget for it) and just create an instance of it as a parameter in the constructor.
In more detail,I created a class named PostHeader and there i created the avatar and the ListTile containing it,then i created an instance of it inside the Post class,so it is not created inside the build method of the Post class.