How can I manage DropDownButton depending on tab? - flutter

Question

I'm trying to make two tabs and put a DropDownButton besidse them.
`
However, I should make DropDownButton dependging on what tab I choose.
For example, if I click tab1, DropDownList1 should apply to DropDownButton, and click Tab2, DropDownList2 should apply to DropDown Button.
I think about use 'int whichTab=1' to manage which tab I choose but I don't know where can I put this variable.
Can you give me some idea to handle it?
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:practice/controller/tabController.dart';
class TabPage extends GetView<TabController> {
const TaboPage ({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Obx(
() =>
DefaultTabController(
length: 3,
child: Scaffold(
backgroundColor: Color(0xff0F9F9F9),
appBar: AppBar(
leading: IconButton(
icon: Icon(
Icons.keyboard_arrow_left_rounded, color: blackcolor),
onPressed: () => Get.back(),
),
titleSpacing: 0,
elevation: 0,
title: const Text(
'tab page',
style: TextStyle(fontSize: 19, fontWeight: FontWeight.bold),
),
bottom: TabBar(
labelColor: Colors.black,
labelStyle: TextStyle(fontWeight: FontWeight.bold),
unselectedLabelStyle: TextStyle(fontWeight: FontWeight.normal),
indicator: UnderlineTabIndicator(
borderSide: BorderSide(width: 2.0, color: maincolor),
insets: EdgeInsets.symmetric(horizontal:30.0),
),
tabs: [
Tab(text: 'Tab1',),
Tab(text: 'Tab2',),
DropdownButtonHideUnderline(
child: DropdownButton<RxString>(
onChanged: (newValue) {
controller.tab1Selected(newValue.toString());
},
value: controller.tab1Selected,
items: [
for (var value in controller.tab1Type)
DropdownMenuItem(
child: Text(value),
value: value.obs,
),
]),)
]
)
),
body: TabBarView(
children: [
SingleChildScrollView(
child: Padding(
padding: EdgeInsets.all(12),
child: Column(
children:[
Box(),
]
)
),
),
SingleChildScrollView(
child: Padding(
padding: EdgeInsets.all(12),
child: Column(
children:[
Box(),
]
)
),
),
],
),
),
),
);
}
Widget Box(context){
return Container();
}
}
import 'package:get/get.dart';
class TabController extends GetxController {
RxInt whichTab=1.obs; //I tried to use it like 1: tab1, 2: tab2
final tab1Type = [
'apple',
'banana',
'mango'
].obs;
RxString tab2Selected = "apple".obs;
final tab2Type = [
'apple',
'banana',
'mango',
'melon'
].obs;
RxString tab2Selected = "apple".obs;
}