Add an item at bottom in listview in Flutter-CodePudding

I'm making an app similar to to-do's app and i can able to add an item from textfield to listview.builder. In this whenever i add a new item it comes below of the todo's list in listview.builder. Now the problem is i make reverse: true inside listview.builder and if i add an item this time it is coming at the top instead at bottom. How can i display the new item at bottom even if it is reverse: true inside listview.builder.

CodePudding user response：

this works, if this is what you wants

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  List<TodoItem> items = [
    TodoItem('first name', ' first body'),
    TodoItem('second name', ' second body'),
    TodoItem('third name', ' third body'),
    TodoItem('fourh name', ' fourh body'),
  ];

  int newCount = 0;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Material App',
      home: Scaffold(
          floatingActionButton: FloatingActionButton(onPressed: () {
            //items.add(TodoItem('${newCount.toString()} new ', ' added ${newCount.toString()} '));
            items.insert(0, TodoItem('${newCount.toString()} new ', ' added ${newCount.toString()} '));
            newCount  ;
            setState(() {});
          }),
          appBar: AppBar(
            title: const Text('Material App Bar'),
          ),
          body: ListView.builder(
              itemCount: items.length,
              reverse: true,
              itemBuilder: ((context, index) {
                return ListTile(
                  title: Text(items[index].name),
                  subtitle: Text(items[index].body),
                );
              }))),
    );
  }
}

class TodoItem {
  final String name;
  final String body;

  TodoItem(this.name, this.body);
}

CodePudding user response：

Say you have a boolean (for reverse) stored in your state, you could then, when adding the item, add it either to the front or the back depending on this value

// State variables
bool isReverse;
List<Todo> todos;

void addListItem(Todo item) {
  if (isReverse) {
    // add to the front of the original array
    todos.insert(0, item);
  } else {
    // add to the back (default case)
    todos.add(item);
  }
}

Though I'd intuitively say that when the list is reversed, you expect new items to end up at the top.

Order example

To illustrate this insertion at index 0 and reverse, I've put the following code and ran it on https://dartpad.dev/

void main() {
  List<String> todos = [];
  
  todos.addAll(['Clean Bedroom', 'Do dishes', 'Cook food']);
  
  print('Normal order: $todos');
  print('Reversed order: ${todos.reversed.toList()}');
  
  // Add item at index 0 (start of the normal list, end of the reversed list)
  todos.insert(0, 'Buy Groceries');
  
  print('Normal order with groceries: $todos');
  print('Reversed order with groceries: ${todos.reversed.toList()}');
}

The output of which is

Normal order: [Clean Bedroom, Do dishes, Cook food]
Reversed order: [Cook food, Do dishes, Clean Bedroom]
Normal order with groceries: [Buy Groceries, Clean Bedroom, Do dishes, Cook food]
Reversed order with groceries: [Cook food, Do dishes, Clean Bedroom, Buy Groceries]