When we want to add the bottom navigation bar, using insert will report an error:
The following RangeError was thrown building BottomNavigationBar(dirty, state:
_BottomNavigationBarState#a56dd(tickers: tracking 3 tickers)):
RangeError (index): Invalid value: Not in range 0..2, inclusive: 3
The solution is to:
bottomList = [
//This way direct assignment is fine
BottomNavigationBarItem(icon: Icon(Icons.home), label: "Home"),
BottomNavigationBarItem(icon: Icon(Icons.add), label: "added"),
BottomNavigationBarItem(icon: Icon(Icons.home), label: "item"),
BottomNavigationBarItem(icon: Icon(Icons. home), label: "My"),
];
replace
bottomList.insert(
1, BottomNavigationBarItem(icon: Icon(Icons.add), label: "added"));
Full code:
import 'dart:async';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:getx_shishi/app_config.dart';
import 'package:getx_shishi/tabs/add_index.dart';
import 'package:getx_shishi/tabs/home_index.dart';
import 'package:getx_shishi/tabs/my_index.dart';
import 'package:getx_shishi/tabs/project_index.dart';
class TabsPage extends StatefulWidget {
const TabsPage({super. key});
@override
State<TabsPage> createState() => _TabsPageState();
}
class _TabsPageState extends State<TabsPage> {
// StreamController controller = StreamController();
StreamController<Map> controller = StreamController. broadcast();
List<BottomNavigationBarItem> bottomList = [
BottomNavigationBarItem(icon: Icon(Icons.home), label: "Home"),
BottomNavigationBarItem(icon: Icon(Icons.home), label: "item"),
BottomNavigationBarItem(icon: Icon(Icons. home), label: "My"),
];
List pageList = [];
// current subscript
int currentIndex = 0;
int index = 0;
@override
void initState() {
super.initState();
getData();
}
@override
void dispose() {
// TODO: implement dispose
super.dispose();
// controller. onCancel();
controller.onCancel!();
}
@override
Widget build(BuildContext context) {
print("Come in and rebuild");
print(bottomList. length);
print("The length of the page----${pageList.length}");
return Scaffold(
bottomNavigationBar: BottomNavigationBar(
currentIndex: currentIndex,
type: BottomNavigationBarType. fixed,
onTap: (value) {
// setState(() {
currentIndex = value;
getData();
// });
},
items: bottomList,
),
body: IndexedStack(
index: currentIndex,
children: pageList.map<Widget>((e) => e["widget"]).toList(),
),
);
}
getData() {
if (index == 0) {
pageList = [
//When initializing
{
"have": false,
"title": "Homepage",
"widget": HomeIndexPage(
streamController: controller, // Writing here is the same as defining and initializing at the beginning (there is a variable control)
),
},
{
"have": false,
"title": "Project",
"widget": ProjectIndexPage(
streamController: controller,
),
},
{
"have": false,
"title": "My",
"widget": MyIndexPage(
streamController: controller,
),
},
];
}
if (index == 0) {
AppConfig. originalIndex = true;
AppConfig. currentIndex = true;
// getContent();
}
if (index == 5) {
AppConfig. originalIndex = false;
}
if (index == 10) {
AppConfig. originalIndex = true;
}
//if()
getContent();
index + + ;
controller.add({"title": pageList[currentIndex]["title"]}); // Click the bottom page to refresh
setState(() {});
}
getContent() {
if (index == 0 & amp; & amp;
AppConfig.originalIndex == true & &
AppConfig. currentIndex == true) {
// This is what came in at the beginning
bottomList.insert(
1,
BottomNavigationBarItem(
icon: Icon(Icons.add), label: "Added")); // But it's right at the beginning, and it's wrong to change it halfway
pageList.insert(
1,
{
"have": true,
"title": "Add",
"widget": AddIndexPage(
streamController: controller,
),
},
);
setState(() {});
controller.add({"title": pageList[currentIndex]["title"]});
return;
}
if (index != 0 & amp; & amp; AppConfig. originalIndex != AppConfig. currentIndex) {
if (AppConfig. originalIndex == false) {
List list = pageList
.where((element) => element["have"])
.toList(); //Check if the added page is included
if (list. isNotEmpty) {
bottomList. removeAt(1);
pageList. removeAt(1);
if (currentIndex >= 1) {
currentIndex = currentIndex - 1;
}
}
AppConfig.currentIndex = AppConfig.originalIndex;
return;
}
if (AppConfig. originalIndex = true) {
List list = pageList
.where((element) => element["have"])
.toList(); //Check if the added page is included
if (list. isEmpty) {
// bottomList.insert(
// 1, BottomNavigationBarItem(icon: Icon(Icons.add), label: "added"));
//You can't write like this here, it will report an error, report a subscript error, and I don't know why
// The following RangeError was thrown building BottomNavigationBar(dirty,
// state:
// _BottomNavigationBarState#a56dd(tickers: tracking 3 tickers)):
// RangeError (index): Invalid value: Not in range 0..2, inclusive: 3
bottomList = [
//This way direct assignment is fine
BottomNavigationBarItem(icon: Icon(Icons.home), label: "Home"),
BottomNavigationBarItem(icon: Icon(Icons.add), label: "added"),
BottomNavigationBarItem(icon: Icon(Icons.home), label: "item"),
BottomNavigationBarItem(icon: Icon(Icons. home), label: "My"),
];
pageList.insert(
1,
{
"have": true,
"title": "Add",
"widget": AddIndexPage(
streamController: controller,
),
},
);
AppConfig.currentIndex = AppConfig.originalIndex;
setState(() {
if (currentIndex >= 1) {
currentIndex = currentIndex + 1;
}
});
}
return;
}
}
}
}