missing_page.dart

import 'dart:async';

import 'package:bencana/missing_add.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:bencana/missing.dart';
import 'package:bencana/utilities.dart';


class MissingPage extends StatefulWidget {
  final disasterId;
  final disasterName;

  const MissingPage({Key key, this.disasterId, this.disasterName}) : super(key: key);
  @override
  _MissingPageState createState() => _MissingPageState(disasterId, disasterName);
}


class _MissingPageState extends State<MissingPage> {
  final disasterId;
  final disasterName;

  var nama;
  var lokasi;
  var status;
  var umur;
  var deskripsi;
  var jenisKelamin;
  var missing;
  var timestamp;


  List<MissingModel> missingList = new List();
  Utilities util = new Utilities();

  // 3. Buat StreamSubscription untuk mendeteksi perubahan database
  //    Ini perlu import dart:async
  StreamSubscription<Event> _onMissingAddedSubscription;
  StreamSubscription<Event> _onMissingChangedSubscription;

  _MissingPageState(this.disasterId, this.disasterName);

  void _onMissingAdded(Event event) {
    print('On missing added...');
    missing = new MissingModel.fromSnapshot(event.snapshot);
    nama = missing.nama;
    lokasi = missing.lokasi;
    jenisKelamin = missing.jenisKelamin;
    umur = missing.umur;
    deskripsi = missing.deskripsi;
    status = missing.status;
    print('Missing Length: $missingList.length');
    print("Nama: $nama, Lokasi: $lokasi, Jenis Kelamin: $jenisKelamin, Umur: $umur, Deskripsi: $deskripsi, Status: $status");
    setState(() {
      missingList.add(missing);
    });
  }

  void _onMissingChanged(Event event) {
    print('On missing changed...');
    missing = new MissingModel.fromSnapshot(event.snapshot);
    setState(() {
      missingList.clear();
      nama = missing.nama;
      lokasi = missing.lokasi;
      status = missing.status;
      jenisKelamin = missing.jenisKelamin;
      umur = missing.umur;
      deskripsi = missing.deskripsi;
      print('Missing Length: $missingList.length');
      print("Nama: $nama, Lokasi: $lokasi, Jenis Kelamin: $jenisKelamin, Umur: $umur, Deskrips: $deskripsi, Status: $status");
      missingList.add(missing);
    });
  }


  @override
  void initState() {
    super.initState();
    final missingRef = FirebaseDatabase.instance.reference().child('missing').child(disasterId);
    missingList.clear();
    _onMissingAddedSubscription =
        missingRef.onChildAdded.listen(_onMissingAdded);
    _onMissingChangedSubscription =
        missingRef.onChildChanged.listen(_onMissingChanged);
  }

  @override
  void dispose() {
    super.dispose();
    _onMissingAddedSubscription.cancel();
    _onMissingChangedSubscription.cancel();
  }


  @override
  Widget build(BuildContext context) {

    return Scaffold(
      appBar: AppBar(title: Text(disasterName),
        actions: <Widget>[
          IconButton(icon: Icon(Icons.add),
            onPressed: (){
              Navigator.push(context, MaterialPageRoute(builder: (context) => MissingAdd(disasterId: disasterId,)));
            },)
        ],),
      body: Container(
        child: Container(
          color: Colors.grey[300],
          child: missingList.length == 0
              ? const Center(child: CircularProgressIndicator())
              : ListView.builder(
            itemBuilder: (BuildContext context, int index) {
              return Card(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        bottom: 10.0,
                        top: 10.0,
                      ),

                      child: Row(
                        children: <Widget>[
                          Text(
                            missingList[index].nama,
                            style: TextStyle(
                              fontWeight:FontWeight.bold,
                              fontSize: 18.0,
                            ),
                          ),

                        ],
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        bottom: 10.0,
                      ),
                      child: Text(
                        'Lokasi : ${missingList[index].lokasi}',
                        style: TextStyle(
                          fontSize: 14.0,
                          color: Colors.grey,
                        ),
                      ),
                    ),

                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        bottom: 10.0,
                      ),
                      child: Text(
                        'Jenis Kelamin : ${missingList[index].jenisKelamin}',
                        style: TextStyle(
                          fontSize: 14.0,
                          color: Colors.grey,
                        ),
                      ),
                    ),


                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        bottom: 10.0,
                      ),
                      child: Text(
                        'Umur : ${missingList[index].umur}',
                        style: TextStyle(
                          fontSize: 14.0,
                          color: Colors.grey,
                        ),
                      ),
                    ),

                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        bottom: 10.0,
                      ),

                      child: Text(
                        'Status : ${missingList[index].status}',
                        style: TextStyle(
                          fontSize: 14.0,
                          color: Colors.grey,
                        ),
                      ),
                    ),


                    Padding(
                      padding: const EdgeInsets.only(
                        left: 16.0,
                        right: 16.0,
                        bottom: 10.0,
                      ),
                      child: Text(
                        'Deskripsi : ${missingList[index].deskripsi}',
                        style: TextStyle(
                          fontSize: 14.0,
                          color: Colors.grey,
                        ),
                      ),
                    ),
                    SizedBox(height: 8.0,),
                  ],
                ),
              );
            },
            itemCount: missingList == null ? 0 : missingList.length,
          ),
        ),
      ),
    );
  }
}