OpenPeerChat-flutter/lib/pages/chat_list_screen.dart

import 'package:provider/provider.dart';
import '../database/database_helper.dart';
import 'package:flutter/material.dart';
import '../classes/global.dart';
import 'chat_page.dart';

/// This is ChatListScreen. This screen lists all the Devices with which the
/// device has chat with and keeps all the previous messages records.

class ChatListScreen extends StatefulWidget {
  const ChatListScreen({Key? key}) : super(key: key);

  @override
 State<ChatListScreen> createState() => _ChatListScreenState();
}

class _ChatListScreenState extends State<ChatListScreen> {
  bool isLoading = false;
  List<String> conversers = [];
  List<String> filteredConversers = [];
  TextEditingController searchController = TextEditingController();


  // In the init state, we need to update the cache everytime.
  @override
  void initState() {
    super.initState();
    readAllUpdateCache();
    searchController.addListener(_filterConversers);
  }


  @override
  void dispose() {
    searchController.removeListener(_filterConversers);
    searchController.dispose();
    super.dispose();
  }


  void _filterConversers() {
    setState(() {
      if (searchController.text.isEmpty) {
        filteredConversers = conversers;
      } else {
        filteredConversers = conversers
            .where((converser) =>
            converser.toLowerCase().contains(searchController.text.toLowerCase()))
            .toList();
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    // Whenever the the UI is built, each converser is added to the list
    // from the conversations map that stores the key as name of the device.
    // The names are inserted into the list conversers here and then displayed
    // with the help of ListView.builder.
    conversers = [];
    Provider.of<Global>(context).conversations.forEach((key, value) {
      conversers.add(key);
    });
    if (searchController.text.isEmpty) {
      filteredConversers = conversers;
    }
    return Column(
      children: [
        Padding(
          padding: const EdgeInsets.only(top: 16, left: 16, right: 16),
          child: TextField(
            controller: searchController,
            decoration: InputDecoration(
              hintText: "Search...",
              hintStyle: TextStyle(color: Colors.grey.shade600),
              prefixIcon: Icon(
                Icons.search,
                color: Colors.grey.shade600,
                size: 20,
              ),
              filled: true,
              fillColor: Colors.grey.shade100,
              contentPadding: const EdgeInsets.all(8),
              enabledBorder: OutlineInputBorder(
                borderRadius: BorderRadius.circular(20),
                borderSide: BorderSide(color: Colors.grey.shade100),
              ),
            ),
          ),
        ),
    Expanded(
    child: ListView.builder(
    itemCount: filteredConversers.length,
    shrinkWrap: true,
    itemBuilder: (context, index) {
    return ListTile(
    title: Text(filteredConversers[index]),
    onTap: () {
    // Navigate to the chat page
    Navigator.push(
    context,
    MaterialPageRoute(
    builder: (context) => ChatPage(
    converser: filteredConversers[index],
    ),
    ),
    );
    },
    );
    },
               ),
        )
      ],
    );
  }
}