Can I change the widget using if? - flutter

Question

For example
if TEXT = "text1'
than page = mainpage(),
else if TEXT = "text2'
than page = mainpage2(),
and
after if the TEXT is other source code string various
how can I cording
:<
plz help me
additional
class Categorylist extends StatefulWidget {
#override
_CategorylistState createState() => _CategorylistState();
}
class _CategorylistState extends State<Categorylist> {
int selectedCategory = 0;
List<String> categories = ["통합정보", "지역 구인글", "나를 위한 구인글", "같은 국가 추천업", "같은 국가 커뮤니티"];
#override
Widget build(BuildContext context) {
return Container(
alignment: Alignment.bottomCenter,
margin: EdgeInsets.symmetric(vertical: kDefaultPadding / 2),
height: 61,
child: ListView.builder(
scrollDirection: Axis.horizontal,
itemCount: categories.length,
itemBuilder: (context, index) => buildCategory(index, context),
),
);
}
Padding buildCategory(int index, BuildContext context) {
return Padding(
padding: const EdgeInsets.symmetric(horizontal: kDefaultPadding),
child: GestureDetector(
onTap: () {
setState(() {
selectedCategory = index;
});
},
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(
categories[index],
style: Theme.of(context).textTheme.bodyText1.copyWith(
fontWeight: FontWeight.w500,
color: index == selectedCategory
? kTextColor
: Colors.black.withOpacity(0.4),
),
),
Container(
margin: EdgeInsets.symmetric(vertical: kDefaultPadding / 2),
alignment: Alignment.center,
height: 6,
width: 40,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(10),
color: index == selectedCategory
? kSecondaryColor
: Colors.transparent,
),
)
],
),
),
);
}
}
class ChangePage extends StatelessWidget {
const ChangePage({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Scaffold(
body: ChangeBody(),
);
}
}
class ChangeBody extends StatelessWidget {
const ChangeBody({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
if (categories == '통합정보') [
ChangeBody() = mainpage()
]
else (categories == '지역 구인글')[
ChangeBody() = RegionJob()
],
],
),;
}
}
this is my code to edit by your advice ,
but I need more help to where insert my if code
and my if code is categories ,ChangeBody() = mainpage() is got redline,

Answer 1

Container(
padding: EdgeInsets.all(8.0),
height: 100,
child: Row(
children: [
true
? Text("No button")
: ElevatedButton(onPressed: () {}, child: Text("button"))
],
),
)
OR
Container(
padding: EdgeInsets.all(8.0),
height: 100,
child: Row(
children: [
if (true)
Text("No button")
else
ElevatedButton(onPressed: () {}, child: Text("button")),
],
),
)
OR
Outside the build method declare mywidget method
Container(
padding: EdgeInsets.all(8.0),
height: 100,
child: Row(
children: [
mywidget(),
],
),
)
mywidget() {
if (true)
return Text("No button");
else
return ElevatedButton(onPressed: () {}, child: Text("button"));
}
OR
Outside the build method declare button variable
var button = true
? Text("No button")
: ElevatedButton(onPressed: () {}, child: Text("button"));
Row(
children: [
mywidget(),
button,
true
? Text("No button")
: ElevatedButton(onPressed: () {}, child: Text("button")),
if (true)
Text("No button")
else
ElevatedButton(onPressed: () {}, child: Text("button")),
],
)
FullCode
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
void main() {
WidgetsFlutterBinding.ensureInitialized();
runApp(MaterialApp(home: Mainwidget()));
}
class Mainwidget extends StatefulWidget {
const Mainwidget({Key? key}) : super(key: key);
#override
_MainwidgetState createState() => _MainwidgetState();
}
class _MainwidgetState extends State<Mainwidget> {
#override
Widget build(BuildContext context) {
return Scaffold(
body: SafeArea(
child: Container(
padding: EdgeInsets.all(8.0),
height: 100,
child: Row(
children: [
mywidget(),
button,
true
? Text("No button")
: ElevatedButton(onPressed: () {}, child: Text("button")),
if (true)
Text("No button")
else
ElevatedButton(onPressed: () {}, child: Text("button")),
],
),
),
),
);
}
mywidget() {
if (true)
return Text("No button");
else
return ElevatedButton(onPressed: () {}, child: Text("button"));
}
var button = true
? Text("No button")
: ElevatedButton(onPressed: () {}, child: Text("button"));
}

Answer 2

You can write if condition like below
if(TEXT == "text1"){
page = mainpage()
}else if(TEXT == "text2"){
page = mainpage2()
}else{
// set your code
}

Answer 3

Method 1
if(TEXT == "text1)
{
page = mainpage();
}
else {
page = mainpage2();
}
Method 2 (using ? operator)
TEXT == "text" ?
page = mainpage() :
page = mainpage2();

Answer 4

use switch case wrapped in builder method. Something like this
enum Options { text1, text2 }
Builder(
builder: (context) {
switch (option) {
case Options.text1:
return Page1();
case Options.text2:
return Page2();
default:
return Page1();
}
},
)

Answer 5

The best way to use if else conditoin on widget is,
Column(
children: [
if (yourCondition == true) ...[
Text(""),
] else ...[
Text(""),
],
],
),