Flutter ListView doesnt update when the underlying list is updated - flutter

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!!

Related

Why does my widget rebuild when I use keyboard

I have this issue of rebuilding widget when The keyboards shows up. I tried to use the sizer package but never could figure out how to get it to work
when I go back from this screen everything in the previous screen will rebuild, Please note: If I don't click on the typeaheadwidget such that the keyboard doesn't show up the state is preserved in the previous screen but as soon as the keyboard pops up the widgets get rebuilt
Could you please check ?
class SearchScreen extends StatefulWidget {
#override
_SearchScreenState createState() => _SearchScreenState();
}
class _SearchScreenState extends State<SearchScreen> {
TextEditingController pickUpTextEditingController = TextEditingController();
TextEditingController dropOffTextEditingController = TextEditingController();
#override
void initState() {
super.initState();
}
#override
#mustCallSuper
Widget build(BuildContext context) {
String placeAddress =
Provider.of<AppData>(context).pickUpLocation.placeName ?? "";
pickUpTextEditingController.text = placeAddress;
return Scaffold(
resizeToAvoidBottomInset: false,
body: Stack(
children: [
Container(
height: 250.0,
decoration: BoxDecoration(
color: Colors.white,
boxShadow: [
BoxShadow(
color: Colors.black,
blurRadius: 6.0,
spreadRadius: 0.5,
offset: Offset(0.7, 0.7),
)
],
),
child: Padding(
padding: EdgeInsets.only(
left: 25.0, top: 30.0, right: 25.0, bottom: 20.0),
child: Column(
children: [
SizedBox(height: 5.0),
Stack(
children: [
GestureDetector(
onTap: () {
Navigator.pop(
//send back data
context,
dropOffTextEditingController.text);
},
child: Icon(Icons.arrow_back)),
Center(
child: Text(
"Set Drop Off",
style: TextStyle(
fontSize: 18.0, fontFamily: "Brand-Bold"),
),
)
],
),
SizedBox(height: 16.0),
Row(
children: [
Image.asset("images/images/pickicon.png",
height: 16.0, width: 16.0),
SizedBox(width: 18.0),
Expanded(
child: Container(
decoration: BoxDecoration(
color: Colors.grey[400],
borderRadius: BorderRadius.circular(5.0),
),
child: Padding(
padding: EdgeInsets.all(3.0),
child: TextField(
controller: pickUpTextEditingController,
decoration: InputDecoration(
hintText: "PickUp Location",
fillColor: Colors.grey[400],
filled: true,
border: InputBorder.none,
isDense: true,
contentPadding: EdgeInsets.only(
left: 11.0, top: 8.0, bottom: 8.0),
),
),
),
))
],
),
SizedBox(height: 10.0),
Row(
children: [
Image.asset("images/images/desticon.png",
height: 16.0, width: 16.0),
SizedBox(width: 18.0),
Expanded(
child: Container(
decoration: BoxDecoration(
color: Colors.grey[400],
borderRadius: BorderRadius.circular(5.0),
),
child: Padding(
padding: EdgeInsets.all(3.0),
child: TypeAheadField(
itemBuilder: null,
onSuggestionSelected: null,
suggestionsCallback: null,
),
),
),
),
],
),
],
),
),
),
],
),
);
}
}
You should not try to control when the build method is called. Flutter will call build when it decides it needs to (e.g. keyboard appears, device rotated, parent rebuilds, etc).
Instead, you should make sure that your build method is a "pure" function. In Flutter specifically, this means that you should not perform any action with "side-effects" (basically anything which modifies the state of the app).
For example:
Widget build(BuildContext context) {
final x = 2 + 3; // fine, nothing else is modified
final state = context.watch<MyModel>(); // also fine, only reading data
controller.text = "hello"; // BAD, modifies the state of the app
return ...;
}
Instead, you should move your logic with side effects into other lifecycle methods (e.g. initState(), didChangeDepencencies(), etc).
For example, if you want to set your text field to a particular string when it first appears, you can use initState:
class _SearchScreenState extends State<SearchScreen> {
#override
void initState() {
super.initState();
final data = context.read<AppData>();
controller.text = data.pickUpLocation.placeName ?? "";
}
Widget build(BuildContext context) {
// ...
}
}
Now build() can be called whenever it has to be, without resetting the state of your text field.
Note that, even if there was some way to prevent your widget from being rebuilt, this is also likely not what you want, since the UI would not update to accommodate the keyboard.
the only reason why your widgets got rebuilds after keyboard pop up.
is that one or more of your widgets size depends on MediaQuery.
you can try to ge your screen size from LayoutBuilder as an alternative for MediaQuery.
Give the textfield an initial value like this:
initvalue:Provider.of<AppData>(context).pickUpLocation.placeName ?? ""
and use onchange method in text field instead of text editing controller like this:
onchange(value){
Provider.of<AppData>(context).pickUpLocation.placeName=value;}
I am also facing the same issue, My blocBuidler is getting rebuilt every time when click on textfield or keyboard is appear.
In my case, I was calling the event in parent BlocBuilder so whenever I pressed on textfields the parent BlocBuilder is called the event, so it builds state of child BlocBuilder
Make sure you are also doing the same thing. If you are doing the same thing please check the state whether it is already built or not.
(BlocProvider.of<YourBlocName>(context).state is YouBlocState) ? Print('do nothing'): BlocProvider.of<YourBlocName>(context).add(youBlocEvent);
When you tap the TextField widget, it makes the keyboard show up. And when the keyboard shows up, your screen size changes. This causes the rebuild

How to remove item at the top of List View in Flutter?

I have List View and I have inside each item in the list a button called "Delete item". When I press that button inside each item I want to delete only that item from the list.
But it does not delete item, it just display Toast message that I have specified.
How I can solve this?
This is the code:
Widget build(BuildContext context) {
listItems = buildVCsFromAPI(context);
return Container(
child: ListView.builder(
itemBuilder: (context, index) =>
_buildListItem(context, listItems[index], index),
itemCount: listItems.length,
physics: AlwaysScrollableScrollPhysics()),
);
}
Widget _buildListItem(
BuildContext context, _VerifiableCredentialListItem cert, int index) {
return GestureDetector(
child: AnimatedAlign(
curve: Curves.ease,
duration: Duration(milliseconds: 500),
heightFactor: selectedPosition == index ? factorMax : factorMin,
alignment: Alignment.topCenter,
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.all(Radius.circular(10)), //here
color: Colors.white,
boxShadow: [
BoxShadow(
color: Colors.grey.withOpacity(0.5),
offset: Offset(0, -1),
blurRadius: 10.0)
]),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
HeadingRow(title: cert.fullTitle, appIcon: cert.appIcon),
displayListItem(index, selectedPosition, cert)
],
),
),
),
}
Column displayListItem(
int index, int selectedIndex, _VerifiableCredentialListItem cert) {
CredentialListGroupType groupType = cert.groupType;
return Column(
crossAxisAlignment: CrossAxisAlignment.center,
children: [
SizedBox(
height: UIConstants.s2,
),
buildAnotherWidget(),
SizedBox(
height: UIConstants.s3,
),
buildDeleteAndExportButtons(),
],
);
}
Column buildDeleteAndExportButtons() {
return Column(
children: [
Padding(
padding: EdgeInsets.symmetric(
vertical: UIConstants.s1, horizontal: UIConstants.s2),
child: Row(
children: [
Expanded(
flex: 1,
child: BlueButtonWithIcon(
text: 'Delete item',
icon: 'assets/icons/delete-icon.svg',
onPressed: () {
setState(() {
AppToaster.pop(ToasterType.info, "Delete");
listItems.removeAt(0);
});
},
),
),
SizedBox(width: UIConstants.s1),
Expanded(
flex: 1,
child: BlueButtonWithIcon(
text: 'Export',
icon: 'assets/icons/export.svg',
onPressed: null,
),
)
],
),
),
SizedBox(height: UIConstants.s1)
],
);
}
Calling setState doesn't mean that flutter would actually full repaint the screen it means that it will check your widget tree with the last rendered widget tree and it will paint only the differences and it first compares widgets type and then widget keys to find that there is a difference between the current widget and the previous one and because of this when you remove an item from your list of items flutter checks your returned widgets to the currently rendered widget it doesn't found any difference and it won't repaint the screen and continues showing the last render
So for you to tell the flutter that one of the items in the listView is changed you could assign a uniqueKey key for each list item widget note that for this topic your keys should be unique to the data of that widget otherwise you will face performance issues because if your widget key is changed without any change in the representation of that widget in next time that builds method is called which could happen frequently flutter compares widgets key with the previous widgets key which is rendered to the screen and exist on the render tree and it founds that the keys are different and it repaints that widget which is a redundant operation because your widgets UI and representation are the same
For example, assign a unique id base on the index or content of your data to each data model in the listItems and use that to create a ValueKey() for the widget that is represented by that data
here is a working example of the list which when you click on the list item first list item will be removed
class ListItemDataModel {
final String id;
final Color color;
ListItemDataModel(this.id, this.color);
}
class _MyHomePageState extends State<MyHomePage> {
List<ListItemDataModel> items = [];
#override
void initState() {
super.initState();
items = [
ListItemDataModel("A", Colors.red),
ListItemDataModel("B", Colors.amber),
ListItemDataModel("C", Colors.green),
ListItemDataModel("D", Colors.lightBlueAccent),
ListItemDataModel("E", Colors.pink),
];
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Container(
child: ListView.builder(
itemBuilder: (context, index) {
return GestureDetector(
key: ValueKey(items[index].id),
//Tap to Remove first item from list
onTap: () {
items.removeAt(0);
setState(() {});
},
child: Container(
height: 60,
color: items[index].color,
child: Center(
child: Text(
"This is a unique item with id = ${items[index].id}"),
),
),
);
},
itemCount: items.length,
),
),
);
}
}
So,
We don't have acces to the code above.. so.. where does listItems came from?
Maybe you are retrieving the value of listItems after the init state? if so it's normal that you are retrieving always the same result..
What you should do is the following:
get listItems value from params, global vars, databse ecc
display the list
when you delete a single item you should update the original list
on state updated now the list will be loaded with updated values
If you delete an item from a list but the list is then reloaded in its original form your updates will be lost

Not able to import variable from a different class in Flutter

I am going off of a login screen tempalte,a nd am trying to get a widget class for a button to just show the username input as an alert on the screen. The usernameinput widget is defined but when I import it, it does not work.
class _InputEmailState extends State<InputEmail> {
final myController = new TextEditingController();
This is the part where I define the input, and this is where I import the class in the button widget:
import 'package:login_minimalist/widget/inputEmail.dart';
When I try and reference the myController.text value, I get the error
The getter 'myController' isn't defined for the class '_ButtonLoginState'.
import 'package:flutter/material.dart';
import 'package:login_minimalist/widget/inputEmail.dart';
class ButtonLogin extends StatefulWidget {
#override
ButtonLoginState createState() => ButtonLoginState();
}
class ButtonLoginState extends State<ButtonLogin> {
#override
Here is the button widget code:
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.only(top: 40, right: 50, left: 200),
child: Container(
alignment: Alignment.bottomRight,
height: 50,
width: MediaQuery.of(context).size.width,
decoration: BoxDecoration(
boxShadow: [
BoxShadow(
color: Colors.blue[300],
blurRadius: 10.0, // has the effect of softening the shadow
spreadRadius: 1.0, // has the effect of extending the shadow
offset: Offset(
5.0, // horizontal, move right 10
5.0, // vertical, move down 10
),
),
],
color: Colors.white,
borderRadius: BorderRadius.circular(30),
),
child: FlatButton(
onPressed: () {
return showDialog(
context: context,
builder: (context) {
return AlertDialog(
// Retrieve the text the user has entered by using the
// TextEditingController.
content: Text(InputEmailState.getUsername),
);
},
);
},
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'Sign in',
style: TextStyle(
color: Colors.lightBlueAccent,
fontSize: 14,
fontWeight: FontWeight.w700,
),
),
Icon(
Icons.arrow_forward,
color: Colors.lightBlueAccent,
),
],
),
),
),
);
And here is the Input code:
class InputEmailState extends State<InputEmail> {
final myController = new TextEditingController();
getUsername() {
return(myController.text);
}
#override
void dispose() {
// Clean up the controller when the widget is disposed.
myController.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.only(top: 50, left: 50, right: 50),
child: Container(
height: 60,
width: MediaQuery.of(context).size.width,
child: TextField(
controller: myController,
style: TextStyle(
color: Colors.white,
),
decoration: InputDecoration(
border: InputBorder.none,
fillColor: Colors.lightBlueAccent,
labelText: 'Student ID',
labelStyle: TextStyle(
color: Colors.white70,
fontSize: 20,
),
),
),
),
);
}
If I understand your question correctly, you're trying to access _ButtonLoginState from another class/file. However, in Dart, classes, members, variables, etc. that begin with an underline ("_") are considered private. You can't access them from a different file (except in some special situations with libraries).
To solve this, you can change the name of the class to ButtonLoginState and it should work.
EDIT: In response to more info:
You don't seem to have fully understood the concepts of State in a StatefulWidget. I would strongly recommend taking a good look through the Flutter guide on the subject.
There are many different ways of managing state and what I am going to explain is almost definitely not the best option most of the time (this was the introductory approach some time ago, but I can't even find the example anymore), however, it does work. For a more general option, I recommend Provider.
In your case, the problem starts with this: Text(InputEmailState.getUsername). You're not calling InputEmailState.getUsername, you're simply passing a reference to it. You need to include parentheses to actually call it - InputEmailState.getUsername().
However, this isn't the whole issue. You're trying to access this function using the name of the class, which means you're trying to use it as a static method. However, its an instance method (ie: you need a specific instance of the class to access it. This is the state I was talking about.
To simply get access to the state object of a specific widget, you can use a Key (generally a GlobalKey). You can define this in a parent widget, for example, and pass it as the key parameter of your InputEmail widget and keep a reference in the parent class. Then, to get the username, you can call <key>.currentState.getUsername() which will return the instance value. The exact implementation varies, and I don't have your code to know how it should be implemented.
As I say, this isn't really the recommended approach anymore. I strongly recommend getting to grips with the state concept, then it should be obvious what the best approach is.

Manage multiple form validation in PageView flutter

I have multiple forms inside a PageView, Forms are in different files like registration_form.dart contains the Sign-Up form and so on. In my App, each page contains a different Form. I want that when the user clicks on "Continue", the form will be validated and in an error situation, the user will be warned. I call all the pages in one class called Body as shown below. The "Continue" button is inside of it in the Opacity container. If there is a better approach to follow as a solution I am open to recommendations.
#override
Widget build(BuildContext context) {
return SafeArea(
child: Center(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Container(
height: MediaQuery.of(context).size.height * 0.65,
child: Flex(
direction: Axis.horizontal,
children: [
Flexible(
child: PageView(
controller: _controller,
//physics: new NeverScrollableScrollPhysics(),
children: [
RegisterForm(),
WelcomeForm(),
//CompanyForm(),
//CompanyNextForm(),
//CompanyLogoForm(),
//FinancingDataForm(),
//UtilityForm(),
//MatrixInformationForm(),
//MatrixInformationNextForm(),
//MatrixInformationLastForm(),
//PriceBuildingForm(),
//InstallKitForm(),
//InstallKitDetailedForm(),
//CustomPricingForm(),
//CustomPricingNextForm(),
//FillRow1Form(),
//FillItem1Row1Form(),
//FillItem2Row1Form(),
//FillItem3Row1Form(),
//FillRow2Form(),
//FillItem1Row2Form(),
//FillItem2Row2Form(),
//FillItem3Row2Form(),
//FillRow3Form(),
//FillItem1Row3Form(),
//FillItem2Row3Form(),
//FillItem3Row3Form(),
//InvoicingForm(),
//FinancingForm(),
//FinancingNextForm(),
//FinancingLastForm(),
//FinalizeForm(),
//DoneForm(),
//BookingForm(),
],
),
),
],
),
),
SizedBox(
height: ResponsiveLayout.isSmallScreen(context)
? 10
: ResponsiveLayout.isMediumScreen(context)
? 10
: 10,
),
Opacity(
opacity: 1, //currentIndex == 20 ? 0 : 1,
child: Container(
height: 50,
decoration: BoxDecoration(
color: Color.fromRGBO(16, 88, 198, 1),
borderRadius: BorderRadius.all(Radius.circular(8)),
),
child: GestureDetector(
onTap: () {
_controller.nextPage(
duration: Duration(milliseconds: 300),
curve: Curves.easeIn);
},
child: Container(
width: MediaQuery.of(context).size.width,
height: 100,
decoration: BoxDecoration(
color: Color.fromRGBO(16, 88, 198, 1),
borderRadius: BorderRadius.all(Radius.circular(8)),
),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Container(
height: 100.0,
child: Center(
child: RichText(
text: TextSpan(children: [
WidgetSpan(
child: Text(
'Continue ',
style: TextStyle(
color: Colors.white,
fontSize: ResponsiveLayout
.isSmallScreen(context)
? 12
: ResponsiveLayout.isMediumScreen(
context)
? 12
: 15,
),
)),
WidgetSpan(
child: Icon(
Icons.arrow_forward,
size: ResponsiveLayout.isSmallScreen(
context)
? 12
: ResponsiveLayout.isMediumScreen(
context)
? 12
: 15,
color: Colors.white,
),
),
]),
),
)),
],
),
),
)),
),
],
),
),
);
}
Okay. I was struggling with the same question recently and was looking for a good approach. Maybe this answer will be helpful for any other developer looking for the answer.
Approach
Currently, in my case, I used form keys for validations and function callbacks. This solution did the job for me because I needed to take input as raw text. Others like multiple choice options similar where there were predefined outputs.
To describe my solution more explicitly. Consider this example, we want to get basic details of the user like name, age, city etc. For user input like the name, we can use TextFormField. This will give access to the onChanged callback for validation. To access the response in the PageView widget containing the class. You can use the TextEditingController.
Now, we can then simply add the Form widget at the parent of the basic form widget build method.
Finally for multiple choice questions. We can provide a callback function like onTap to the widget of PageView. This function will be called whenever the user interacts with the dropdown or similar widget.
Note: If we have multiple forms in the PageView widget. You will be needing separate form keys for individual forms.
Code Example
So, we have the main form_screen.dart containing the PageView widget and basic_profile.dart containing our form. Both the files should look something like this:
form_screen.dart
...
// define the variables and keys here
final _basicProfileKey = GlobalKey<FormState>();
final _userName = TextEditingController();
late String _userGender;
...
// callback function that we will be passing to the BasicProfile
// widget on the other page
void _userGender(String value) {
_userGender = value;
}
...
// the submission callback that will be called whenever the user
// clicks on the next or save button available in the class file
// (this file) containing the PageView widget
void _submissionCallback(){
if(_pageViewIndex == 0) {
final validationStatus = _basicProfileKey.currentState?.validate() ?? false;
if(validationStatus) {
// implement your logic here and then move to next page in the pageview
}
}
}
...
// Build method widget tree containing the PageView and BasicProfile
// widgets
child: PageView(
children: [
BasicProfile(
basicProfileKey: _basicProfileKey,
userName: _userName,
userGenderCallback: userGender
),
]
),
basic_profile.dart
...
// declare the variables for this widget which we will be initialised
// via constructor
final GlobalKey<FormState> basicProfileKey;
final TextEditingController userName;
final Function(String) userGenderCallback;
...
#override
void initState(){
// initialise the default values here if any and call the
// callback function received above
userGenderCallback(_defaultValue);
}
...
Widget build(BuildContext context){
...
child: Form(
key: basicProfileKey,
...
TextFieldForm(
onValidate: (){
// do the validation here
}
)
...
DropDown(
onChanged: (value) {
// logic for validation
userGenderCallback(value);
}
)
}
In my approach used setState as the state management solution but other state solutions can also be used for easier state sharing between the widgets.
Hope this helps!

Flutter snackbar alternative or easier method than wrapping everything in Scaffold?

I'm working on my first Flutter app (debugging on my Android phone). I have a list with row items. When you long-press the row, it copies the content into the user's clipboard. This is working great!
But I need to let the user know that the content was copied.
I've attempted to follow many tutorials on trying to get the row surrounded by a build method or inside a Scaffold, but I can't get any to work. Is there an alternative method to notifying the user (simply) that something like "Copied!" took place?
Notice the commented out Scaffold.of(... below. It just seems like there must be an easier method to notifying the user other than wrapping everything in a Scaffold. (and when I try, it breaks my layout).
import 'package:flutter/material.dart';
import 'package:my_app/Theme.dart' as MyTheme;
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/services.dart';
class RowRule extends StatelessWidget {
final DocumentSnapshot ruleGroup;
RowRule(this.ruleGroup);
_buildChildren() {
var builder = <Widget>[];
if (!ruleGroup['label'].isEmpty) {
builder.add(new Text(ruleGroup['label'],
style: MyTheme.TextStyles.articleContentLabelTextStyle));
}
if (!ruleGroup['details'].isEmpty) {
builder.add(new Text(ruleGroup['details'],
style: MyTheme.TextStyles.articleContentTextStyle));
}
return builder;
}
#override
Widget build(BuildContext context) {
return new GestureDetector(
onLongPress: () {
Clipboard.setData(new ClipboardData(text: ruleGroup['label'] + " " + ruleGroup['details']));
// Scaffold.of(context).showSnackBar(SnackBar
// (content: Text('text copied')));
},
child: Container(
margin: const EdgeInsets.symmetric(vertical: 3.0),
child: new FlatButton(
color: Colors.white,
padding: EdgeInsets.symmetric(horizontal: 0.0),
child: new Stack(
children: <Widget>[
new Container(
margin: const EdgeInsets.symmetric(
vertical: MyTheme.Dimens.ruleGroupListRowMarginVertical),
child: new Container(
child: Padding(
padding: EdgeInsets.symmetric(horizontal: 32.0, vertical: 8.0),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: _buildChildren(),
),
)),
)
],
),
),
));
}
}
The goal is to have a page like this (see image), which I have, and it works and scrolls...etc, but I cannot get it to work with a Scaffold, and therefore, haven't been able to use the snackbar. Each "Row" (which this file is for) should show a snackbar on longPress.
You can use GlobalKey to make it work the way you want it.
Since I don't have access to your database stuff, this is how I gave you an idea to do it. Copy and paste this code in your class and make changes accordingly. I also believe there is something wrong in your RowRule class, can you just copy the full code I have given you and run?
void main() => runApp(MaterialApp(home: HomePage()));
class HomePage extends StatelessWidget {
final GlobalKey<ScaffoldState> _key = GlobalKey();
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Color(0xFFFFFFFF).withOpacity(0.9),
key: _key,
body: Column(
children: <Widget>[
Container(
color: Color.fromRGBO(52, 56, 245, 1),
height: 150,
alignment: Alignment.center,
child: Container(width: 56, padding: EdgeInsets.only(top: 12), decoration: BoxDecoration(shape: BoxShape.circle, color: Colors.yellow)),
),
Expanded(
child: ListView.builder(
padding: EdgeInsets.zero,
itemCount: 120,
itemBuilder: (context, index) {
return Container(
color: Colors.white,
margin: const EdgeInsets.all(4),
child: ListTile(
title: Text("Row #$index"),
onLongPress: () => _key.currentState
..removeCurrentSnackBar()
..showSnackBar(SnackBar(content: Text("Copied \"Row #$index\""))),
),
);
},
),
),
],
),
);
}
}
These is a simple plugin replacement for the Snackbar named "Flushbar".
You can get the plugin here - https://pub.dartlang.org/packages/flushbar
You don't have to take care of any wrapping of widgets into scaffold also you get a lot of modifications for you like background gradient, adding forms and so on into Snackbar's and all.
Inside your onLongPressed in GestureDetectore you can do this.
onLongPressed:(){
Clipboard.setData(new ClipboardData(text: ruleGroup['label'] + " " + ruleGroup['details']));
Flushbar(
message: "Copied !!",
duration: Duration(seconds: 3),
)..show(context);
}
This will display the snackbar in you app where you would want to see it also you can get a lot of modification available to you so the you can make it look as per your app.
There are couple of things you need to do, like use onPressed property of the FlatButton it is mandatory to allow clicks, wrap your GestureDetector in a Scaffold. I have further modified the code so that it uses GlobalKey to make things easy for you.
Here is the final code (Your way)
class RowRule extends StatelessWidget {
final GlobalKey<ScaffoldState> globalKey = GlobalKey();
final DocumentSnapshot ruleGroup;
RowRule(this.ruleGroup);
_buildChildren() {
var builder = <Widget>[];
if (!ruleGroup['label'].isEmpty) {
builder.add(new Text(ruleGroup['label'], style: MyTheme.TextStyles.articleContentLabelTextStyle));
}
if (!ruleGroup['details'].isEmpty) {
builder.add(new Text(ruleGroup['details'], style: MyTheme.TextStyles.articleContentTextStyle));
}
return builder;
}
#override
Widget build(BuildContext context) {
return Scaffold(
key: globalKey,
body: GestureDetector(
onLongPress: () {
Clipboard.setData(new ClipboardData(text: ruleGroup['label'] + " " + ruleGroup['details']));
globalKey.currentState
..removeCurrentSnackBar()
..showSnackBar(SnackBar(content: Text('text copied')));
},
child: Container(
margin: const EdgeInsets.symmetric(vertical: 3.0),
child: new FlatButton(
onPressed: () => print("Handle button press here"),
color: Colors.white,
padding: EdgeInsets.symmetric(horizontal: 0.0),
child: new Stack(
children: <Widget>[
new Container(
margin: const EdgeInsets.symmetric(vertical: MyTheme.Dimens.ruleGroupListRowMarginVertical),
child: new Container(
child: Padding(
padding: EdgeInsets.symmetric(horizontal: 32.0, vertical: 8.0),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: _buildChildren(),
),
),
),
)
],
),
),
),
),
);
}
}
I made a dropdown banner package on pub that allows you to easily notify users of errors or confirmation of success. It's a work in progress as I continue to add visually rich features.
I am not sure if your build() method is completed or you are yet to change it, because it consist of many widgets which are just redundant. Like there is no need to have Container in Container and further Padding along with a FlatButton which would make complete screen clickable. Also having Column won't be a good idea because your screen may overflow if you have more data. Use ListView instead.
So, if you were to take my advice, use this simple code that should provide you what you are really looking for. (See the build() method is of just 5 lines.
class RowRule extends StatelessWidget {
final GlobalKey<ScaffoldState> globalKey = GlobalKey();
final DocumentSnapshot ruleGroup;
RowRule(this.ruleGroup);
_buildChildren() {
var builder = <Widget>[];
if (!ruleGroup['label'].isEmpty) {
builder.add(
ListTile(
title: Text(ruleGroup['label'], style: MyTheme.TextStyles.articleContentLabelTextStyle),
onLongPress: () {
globalKey.currentState
..removeCurrentSnackBar()
..showSnackBar(SnackBar(content: Text("Clicked")));
},
),
);
}
if (!ruleGroup['details'].isEmpty) {
builder.add(
ListTile(
title: Text(ruleGroup['details'], style: MyTheme.TextStyles.articleContentTextStyle),
onLongPress: () {
globalKey.currentState
..removeCurrentSnackBar()
..showSnackBar(SnackBar(content: Text("Clicked")));
},
),
);
}
return builder;
}
#override
Widget build(BuildContext context) {
return Scaffold(
key: globalKey,
body: ListView(children: _buildChildren()),
);
}
}
I read your comments on all answers and here is my conslusion:
You need ScaffoldState object that is just above the widget in tree to show Snackbar. You can either get it through GlobalKey as many have suggested. Fairly simple if the Scaffold is created inside build of the widget, but if it is outside the widget (in your case) then it becomes complicated. You need to pass that key, wherever you need it through Constructor arguments of child widgets.
Scaffold.of(context) is a very neat way to just do that. Just like an InheritedWidget, Scaffold.of(BuildContext context) gives you access of the closest ScaffoldState object above the tree. Else it could be a nightmare to get that instance (by passing it through as constructor arguments) if your tree was very deep.
Sorry, to disappoint but I don't think there is any better or cleaner method than this, if you want to get the ScaffoldState that is not built inside build of that widget. You can call it in any widget that has Scaffold as a parent.