missing_list.dart

import 'dart:async';

import 'package:bencana/disaster.dart';
import 'package:bencana/disaster_page.dart';
import 'package:bencana/missing_page.dart';
import 'package:bencana/utilities.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';

class MissingList extends StatefulWidget {
  @override
  _MissingListState createState() => _MissingListState();
}

class _MissingListState extends State<MissingList> {
  var title;
  var timeStamp;
  var disaster;
  var disasterId;

  List<Disaster> disasterList = new List();

  Utilities util = new Utilities();

  final disasterRef = FirebaseDatabase.instance.reference().child('disasters');

  StreamSubscription<Event> _onDisasterAddedSubscription;
  StreamSubscription<Event> _onDisasterChangedSubscription;

  void _onDisasterAdded(Event event) {
    print('On disaster added...');
    disaster = new Disaster.fromSnapshot(event.snapshot);
    title = disaster.title;
    disasterId = disaster.disasterId;
    print('Disaster Length: $disasterList.length');
    setState(() {
      disasterList.add(disaster);
    });
  }

  void _onDisasterChanged(Event event) {
    print('On disaster changed...');
    disaster = new Disaster.fromSnapshot(event.snapshot);
    setState(() {
      disasterList.clear();
      title = disaster.title;
      disasterId = disaster.disasterId;
      print('Disaster Length: $disasterList.length');
      disasterList.add(disaster);
    });
  }


  @override
  void initState() {
    super.initState();
    disasterList.clear();
    _onDisasterAddedSubscription =
        disasterRef.onChildAdded.listen(_onDisasterAdded);
    _onDisasterChangedSubscription =
        disasterRef.onChildChanged.listen(_onDisasterChanged);
  }


  @override
  void dispose() {
    super.dispose();
    _onDisasterAddedSubscription.cancel();
    _onDisasterChangedSubscription.cancel();
  }

  @override
  Widget build(BuildContext context) {

    return Center(
      child: Container(
        color: Colors.grey[300],
        child: disasterList.length == 0
            ? const Center(child: CircularProgressIndicator())
            : ListView.builder(
          itemBuilder: (BuildContext context, int index) {
            print('----------disasterId : $disasterId');
            return GestureDetector(
              onTap: (){
                Navigator.push(context, MaterialPageRoute(builder: (context) => MissingPage(disasterId: disasterList[index].disasterId, disasterName: disasterList[index].title,)));
              },
              child: Card(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        bottom: 10.0,
                        top: 16.0,
                      ),
                      child: Text(
                        disasterList[index].title,
                        style: TextStyle(
                          fontSize: 18.0,
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        top: 5.0,
                        bottom: 5.0,
                      ),
                      child: Text(
                        util.convertTimestamp(
                          disasterList[index].timestamp,
                        ),
                        style: TextStyle(
                          fontSize: 14.0,
                          color: Colors.grey,
                        ),
                      ),
                    ),
//                        RaisedButton(onPressed: null),
                  ],
                ),
              ),
            );
          },
          itemCount: disasterList == null ? 0 : disasterList.length,
        ),
      ),
    );
  }
}