Issue
import 'package:flutter/material.dart';
import 'package:todoapp/data/data.dart';
import 'package:todoapp/data/task.dart';
class TodoHome extends StatefulWidget {TodoHome({Key? key}) : super(key: key);
@override
_TodoHomeState createState() => _TodoHomeState();
}
class _TodoHomeState extends State<TodoHome> {
Color mainColor= Color(0XFF0d0952);
Color secondColor=Color(0XFF212061);
Color btnColor=Color(0XFFff955b);
Color editorColor=Color(0XFF4044CC);
TextEditingController inputcontroller= TextEditingController();
String newTasktxt='';
getTasks()async{
final tasks =await DBProvider.dataBase.getTasks();
print(tasks);
return tasks;
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
elevation: 0.0,
backgroundColor: mainColor,
title: Text("BMS ToDo",style: TextStyle(
fontSize: 20.0,
fontStyle: FontStyle.italic,
),),
centerTitle: true,
),
backgroundColor: mainColor,
body: Column(
children: [
Expanded(child: FutureBuilder(
future: getTasks (),
builder: (_,taskData) {
switch (taskData.connectionState) {
case ConnectionState.waiting:
{
return Center(child: CircularProgressIndicator());
}
case ConnectionState.done:
{
if (taskData.data != Null) {
return Padding(padding: const EdgeInsets.all(9.0),
child: ListView.builder(
itemCount: taskData.data.length,
itemBuilder:( context, index) {
String task= taskData.data [index]['task'].toString();
String day= DateTime.parse(taskData.data [index]['creationDate']).day
.toString();
return Card(
color: secondColor,
child: InkWell(
onTap: (){},
child: Row(
children: [
Container(
margin: EdgeInsets.only(right: 20.0),
padding: EdgeInsets.all(8.0),
decoration: BoxDecoration(
color: Colors.redAccent,
borderRadius: BorderRadius.circular(12.0),
),
child: Text(day),
),
Expanded(child: Padding(
padding: EdgeInsets.all(9.0),
child:
Text(task)),
),
],
),
),
);
},
),
);
} else{
return Center(
child: Text('Enter Your Task'),
);
}
}
case ConnectionState.none:
break;
case ConnectionState.active:
break;
}
}
)),
Container(
padding: EdgeInsets.symmetric(horizontal: 12.0,vertical: 18.0),
decoration: BoxDecoration(color: editorColor,borderRadius: BorderRadius.only(
topLeft: Radius.circular(19.0),
topRight: Radius.circular(19.0),
)),
child: Row(
children: [
Expanded(child:TextField(
controller: inputcontroller,
decoration: InputDecoration(
filled: true,
fillColor: Colors.white70,
hintText: "Enter Your Task",
focusedBorder: InputBorder.none,
),
),),
SizedBox(width: 14.0),
FlatButton.icon(icon: Icon(Icons.add), label: Text("Add Task"),
color: btnColor,
shape: StadiumBorder(),
onPressed: (){
setState(() {
newTasktxt=inputcontroller.text.toString();
inputcontroller.text='';
});
Task newTask=Task(task: newTasktxt,datetime: DateTime.now() );
DBProvider.dataBase. addnewtask(newTask);
},),
],
),
),
],
),
);
}
}
*The body might complete normally, causing ‘null’ to be returned, but the return type is a potentially non-nullable type.
Try adding either a return or a throw statement at the end.
*The property ‘length’ can’t be unconditionally accessed because the receiver can be ‘null’.
Try making the access conditional (using ‘?.’) or adding a null check to the target (‘!’).
*The property ‘length’ can’t be unconditionally accessed because the receiver can be ‘null’.
Try making the access conditional (using ‘?.’) or adding a null check to the target (‘!’).
*The method ‘[]’ can’t be unconditionally invoked because the receiver can be ‘null’.
Try making the call conditional (using ‘?.’) or adding a null check to the target (‘!’).
Solution
On your FutureBuilder, the widget is not returning widget for every possible cases, you need to handle other states, replace Container with your widget.
....
case ConnectionState.none:
return Container();
case ConnectionState.active:
return Container();
default:
return Container();
Second issue is coming from null-safety, you need to check data if it is null , then assign it
like for itemCount
itemCount: taskData.data?.length,
String task = taskData.data == null
? "no data found"
: taskData.data![index]['task'].toString();
Do the same for others.
Check more about null-safety
Answered By – Yeasin Sheikh
Answer Checked By – Pedro (FlutterFixes Volunteer)