Flutter : unable to reuse views in appdrawer - dart

Question

File:homepage.dart
class _HomePageState extends State<HomePage> {
var _scaffoldBody;
var _scaffoldTitle;
#override
initState() {
_scaffoldTitle=new Text("Wall");
_scaffoldBody=new Center(child:CircularProgressIndicator());
}
#override
Widget build(BuildContext context) {
return Scaffold(
drawer: new Drawer(
child: ListView(
padding: EdgeInsets.zero,
children: <Widget>[
DrawerHeader(
child: Text('Drawer Header'),
decoration: BoxDecoration(
color:Theme.of(context).accentColor,
),
),
ListTile(
title: Text('Home'),
onTap: () {
setState(() {
_scaffoldTitle=new Text("Home");
_scaffoldBody=new Text("Home Page");
});
Navigator.pop(context);
},
),
ListTile(
title: Text('MenuItem1'),
onTap: () {
setState(() {
_scaffoldTitle=new Text("1st Menu");
_scaffoldBody=new TestPage("Page 1");
});
Navigator.pop(context);
},
),
ListTile(
title: Text('MenuItem2'),
onTap: () {
setState(() {
_scaffoldTitle=new Text("2nd Item");
_scaffoldBody=new TestPage("Page 2");
});
Navigator.pop(context);
},
),
],
),
),
appBar: new AppBar(
title: _scaffoldTitle,
elevation: 2.0,
actions: <Widget>[
],
),
body:_scaffoldBody,
);
}
file: TestPage.dart
import 'package:flutter/material.dart';
class TestPage extends StatefulWidget{
final String rollNumber;
TestPage(this.rollNumber);
#override
TestPageState createState() => new TestPageState(rollNumber);
}
class TestPageState extends State<TestPage>{
String rollNumber;
TestPageState(this.rollNumber);
#override
Widget build(BuildContext context) {
return new Text(rollNumber);
}
}
Output:
When I chose : "Home" from drawer it shows "Home Page"
Then I chose : "MenuItem1" it showed "Page 1"
Then I chose : "MenuItem2" it showed same "Page 1" (unexpected)
Then I chose : "Home" it showed "Home Page"
Then I chose : "MenuItem2" it showed correctly as "Page 2"
Then I chose : "MenuItem1" it showed "Page 2" (unexpected)
unable to solve this.Stuck!! Any solutions are appreciated. Thanks in advance!!

Answer 1

Update your TestPart.dart as follow:
import 'package:flutter/material.dart';
class TestPage extends StatefulWidget{
final String rollNumber;
TestPage(this.rollNumber);
#override
TestPageState createState() => new TestPageState();
}
class TestPageState extends State<TestPage>{
#override
Widget build(BuildContext context) {
return new Text(widget.rollNumber);
}
}

Answer 2

My StudentPage Class
import 'package:flutter/material.dart';
import 'package:firebase_database/firebase_database.dart';
import 'calendar_utils.dart';
import 'dart:async';
final mainReference = FirebaseDatabase.instance.reference();
class StudentPage extends StatefulWidget{
final String rollNumber;
StudentPage(this.rollNumber);
#override
StudentPageState createState() => new StudentPageState(rollNumber);
}
class StudentPageState extends State<StudentPage>{
final String currentRoll,currentYear="2018-19";
StudentPageState(this.currentRoll);
List<String> academicMonth=["June","July","August","September","October","November","December",
"January","February","March","April","May"];
int firstHalfYear=2018,secondHalfYear=2019;
List<Widget> _monthListArray=[new ListTile(title:new Text("Academic Year",style: new TextStyle(fontWeight: FontWeight.bold,fontSize: 20.0),),)];
List<Widget> _listView;
int _no_of_working=0;
int _no_of_present=0;
#override
void initState() {
// TODO: implement initState
_listView=[new Center(
child: new CircularProgressIndicator(),
)];
_loadMonths();
}
#override
Widget build(BuildContext context) {
return new RefreshIndicator(child: new ListView(
children: _listView,
), onRefresh: _loadMonths);
}
Future<Null> _loadMonths() async {
_listView.clear();
await mainReference.child("XXXX").child("attendance").child(
widget.rollNumber).child(currentYear).once().then((
DataSnapshot dataSnapshot) {
try {
int monthIndex=5; //monthIndex starts from June
for(var month in academicMonth){
debugPrint("Month:"+month);
monthIndex=(monthIndex+1)%12; //month index cycles throughout 1-12
if(monthIndex==0) monthIndex=12;
List<Widget> _daysList=[];
_monthListArray.add(new Padding(padding: EdgeInsets.all(16.0),child: new Text(month+" "+(monthIndex<6?secondHalfYear:firstHalfYear).toString(),style: new TextStyle(color: Colors.black87,fontWeight: FontWeight.bold,fontSize: 20.0),),)); //initializing the month
_monthListArray.add(new Padding(padding: EdgeInsets.only(top: 10.0,bottom: 10.0),child:
new Row(children: <Widget>[
new Expanded(
child: new Center(child: new Text("S",style: new TextStyle(fontWeight: FontWeight.bold),),),
),
new Expanded(
child: new Center(child: new Text("M",style: new TextStyle(fontWeight: FontWeight.bold),),),
),
new Expanded(
child: new Center(child: new Text("T",style: new TextStyle(fontWeight: FontWeight.bold),),),
),
new Expanded(
child: new Center(child: new Text("W",style: new TextStyle(fontWeight: FontWeight.bold),),),
),
new Expanded(
child: new Center(child: new Text("T",style: new TextStyle(fontWeight: FontWeight.bold),),),
),
new Expanded(
child: new Center(child: new Text("F",style: new TextStyle(fontWeight: FontWeight.bold),),),
),
new Expanded(
child: new Center(child: new Text("S",style: new TextStyle(fontWeight: FontWeight.bold),),),
),
],),));
debugPrint(monthIndex.toString());
int freeSpace=CalendarUtils(1,monthIndex,monthIndex<6?secondHalfYear:firstHalfYear).getDayFromDate();
debugPrint("FreeSpace---"+freeSpace.toString());
if(freeSpace!=0){
for (var i = 0; i < freeSpace; i++) {
_daysList.add(new Text(""));
}
}
debugPrint(monthIndex.toString());
var year=monthIndex<6?secondHalfYear:firstHalfYear;
debugPrint("Year"+year.toString());
debugPrint("Forloop limit:"+CalendarUtils(1,monthIndex,monthIndex<6?firstHalfYear:secondHalfYear).numberOfDays().toString());
for(var day=1;day<=CalendarUtils(1,monthIndex,monthIndex<6?secondHalfYear:firstHalfYear).numberOfDays();day++){
try {
//debugPrint(day.toString()+":"+dataSnapshot.value[month][day].toString());
if (CalendarUtils(day, monthIndex,
monthIndex < 6 ? secondHalfYear: firstHalfYear)
.getDayFromDate() != 0){
if (dataSnapshot.value[month][day].toString() == "1") {
_no_of_working++;
_no_of_present++;
_daysList.add(
new Padding(padding: EdgeInsets.only(left: 10.0,right: 10.0,top: 2.0,bottom: 2.0),
child: new Container(
alignment: Alignment.center,
width: 30.0,
height: 30.0,
decoration: new BoxDecoration(
borderRadius: new BorderRadius.all(new Radius.circular(50.0)),
color: Colors.green),
child: new Text(
day.toString(),
style: new TextStyle(color: Colors.white),
),
),
)
);
}
else if (dataSnapshot.value[month][day].toString() == "0"){
_no_of_working++;
_daysList.add(
new Padding(padding: EdgeInsets.only(left: 10.0,right: 10.0,top: 2.0,bottom: 2.0),
child: new Container(
alignment: Alignment.center,
width: 30.0,
height: 30.0,
decoration: new BoxDecoration(
borderRadius: new BorderRadius.all(new Radius.circular(50.0)),
color: Colors.redAccent),
child: new Text(
day.toString(),
style: new TextStyle(color: Colors.white),
),
),
)
);
}
else {
_daysList.add(
new Padding(padding: EdgeInsets.only(left: 10.0,right: 10.0,top: 2.0,bottom: 2.0),
child: new Container(
alignment: Alignment.center,
width: 30.0,
height: 30.0,
decoration: new BoxDecoration(
borderRadius: new BorderRadius.all(new Radius.circular(50.0)),
),
child: new Text(
day.toString(),
style: new TextStyle(color: Colors.black),
),
),
)
);
}
}else {
_daysList.add(
new Center(child: new Text(day.toString(), style:
new TextStyle(color: Colors.black45),)));
}
}catch (e){
_daysList.add(new Center(child:new Text(day.toString(),style:
new TextStyle(color: Colors.black),) ));
}
}
Widget _daysGrid=new GridView.count(crossAxisCount: 7,
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
childAspectRatio: 1.5,
children: _daysList,
);
_monthListArray.add(_daysGrid);
}
}catch(e){}
_monthListArray.add(new Text((_no_of_present/_no_of_working).toString()));
});
this.setState((){
_listView=_monthListArray;
});
}
}

Answer 3

My HomePage.dart
import 'package:flutter/material.dart';
import 'package:smart_school_parent/TestPage.dart';
import 'package:smart_school_parent/attendance.dart';
import 'package:smart_school_parent/post.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:smart_school_parent/auth.dart';
import 'dart:async';
class HomePage extends StatefulWidget {
final BaseAuth auth;
final VoidCallback onSignOut;
HomePage({Key key, this.auth, this.onSignOut}) : super(key: key);
#override
_HomePageState createState() => new _HomePageState(this.auth);
}
class _HomePageState extends State<HomePage> {
final mainReference = FirebaseDatabase.instance.reference();
List<PostData> post_list = new List();
var _scaffoldBody;
var _loading;
var _currentYear;
var _scaffoldTitle;
List<Widget> _childrenList=[new Text("Profiles",textAlign: TextAlign.left,style: new TextStyle(fontWeight: FontWeight.bold),)];
BaseAuth auth;
_HomePageState(this.auth);
#override
initState() {
//_children=updateChildren();
_updateChildren();
getList();
_loading=true ;
_scaffoldTitle=new Text("Wall");
_scaffoldBody=new Center(child:CircularProgressIndicator());
}
#override
Widget build(BuildContext context) {
return Scaffold(
drawer: new Drawer(
child: ListView(
// Important: Remove any padding from the ListView.
padding: EdgeInsets.zero,
children: <Widget>[
DrawerHeader(
child: Text('XXXXx'),
decoration: BoxDecoration(
color:Theme.of(context).accentColor,
),
),
ListTile(
title: Text('Wall'),
onTap: () {
setState(() {
_scaffoldTitle=new Text("Wall");
_scaffoldBody=new RefreshIndicator(child: _loadWall(), onRefresh: getList);
});
Navigator.pop(context);
},
),
Column(
children: _childrenList,
),
],
),
),
appBar: new AppBar(
title: _scaffoldTitle,
elevation: 2.0,
actions: <Widget>[
],
),
body:_scaffoldBody,
);
}
Future <Null> getList() async {
await mainReference.child("NISE-Coimbatore").child("posts").once().then((DataSnapshot dataSnapshot) {
this.setState(() {
post_list.clear();
if(dataSnapshot.value!=null){
for (var value in dataSnapshot.value.values) {
post_list.add(new PostData.fromJson(value));
//debugPrint(value.toString());
}
}else{
this.setState((){
});
}
});
});
setState(() {
_scaffoldBody=new RefreshIndicator(child: _loadWall(), onRefresh: getList);
});
}
Widget _loadWall(){
return Stack(
children: <Widget>[
new ListView.builder(itemBuilder: (BuildContext context,int index){
return new Post(post_list[index].image,post_list[index].title,post_list[index].content);
},
itemCount: post_list == null ? 0 : post_list.length,)
],
);
}
_updateChildren() async {
_currentYear= await mainReference.child("attendance").child("currentYear").once();
await auth.currentUser().then((String userId) async{
mainReference.child("NISE-Coimbatore").child("parents").child(userId).child('children').once().then((DataSnapshot dataSnapshot){
for (var value in dataSnapshot.value){
this.setState((){
_childrenList.add(
new Padding(
padding: EdgeInsets.only(left: 25.0),
child: ListTile(
title: Text(value.toString()),
onTap: () {
super.setState(() {
_scaffoldTitle=new Text(value.toString());
this._scaffoldBody=new StudentPage(value.toString());
});
Navigator.pop(context);
},
),
),
);
});
//debugPrint("Childrrncount::"+value.toString());
}
});
});
}
}
class PostData{
String title;
String content;
String image;
PostData(this.title, this.content, this.image);
PostData.fromJson(var value) {
this.title = value['title'];
this.content = value['content'];
this.image = value['image'];
}
}
_childrenList has two elements. The datasnapshot.values has [15505,15501] two roll numbers
Both rollnumbers from firebase appear on the drawer box and on tap it is expected to show StudentPage(15501.tostring()) or StudentPage(15505.tostring())
it works as expected if select "Wall" from drawer and then any of the "rollNumbers"
it is not working if i switch from one of the rollNumbers to other rollNumber in the drawer.
Similar to my first post. Only the _scaffoldTitle changes accordingly.