Flutter-Pagination.dart

import 'package:flutter/material.dart';
import 'package:oyobill/base/BaseState.dart';
import 'package:oyobill/data/network/APIs.dart';
import 'package:oyobill/data/network/api_response/TopupHistoryResponse.dart';
import 'package:oyobill/ui/history/topup_history/topup_history_contract.dart';
import 'package:intl/intl.dart';

class TopupHistory extends StatefulWidget {

  static const route = "/topup-history";

  @override
  _TopupHistoryState createState() => new _TopupHistoryState();
}

class _TopupHistoryState extends BaseState<TopupHistory>
    implements TopupHistoryView {

  // Pagination
  List<SingleTopup> _hisotories = [];
  final GlobalKey<RefreshIndicatorState> _refreshIndicatorKey = GlobalKey<
      RefreshIndicatorState>();
  ScrollController _scrollController = ScrollController();
  String _nextPageUrl;
  bool _isFirstTimeLoading = false;
  bool _isPaginating = false;

  TopupHistoryPresenterImpl _presenter;


  @override
  void initState() {
    super.initState();
    _scrollController.addListener(() {
      if (_scrollController.position.pixels ==
          _scrollController.position.maxScrollExtent) {
        if (_nextPageUrl != null && _isPaginating == false) {
          loadMoreData();
        }
      }
    });
    _presenter = TopupHistoryPresenterImpl(this);
    _isFirstTimeLoading = true;
    _presenter.getTopUpHistory(APIs.TOPUP_HISTORY);
  }

  @override
  void dispose() {
    _scrollController.dispose();
    super.dispose();
  }

  Widget _buildProgressIndicator() {
    return Padding(
      padding: EdgeInsets.all(8.0),
      child: Center(
        child: Opacity(opacity: _isPaginating ? 1.0 : 00,
            child: CircularProgressIndicator()),
      ),
    );
  }

  Widget _buildItemView(SingleTopup singleTopUp) {
    return Column(
      children: <Widget>[
        Container(
          padding: EdgeInsets.symmetric(vertical: 14, horizontal: 8),
          child: Row(
            children: <Widget>[
              Expanded(
                  child: Center(
                      child: Column(
                        children: <Widget>[
                          Text(DateFormat("dd MMM, yyyy").format(
                              DateFormat("yyyy-MM-dd HH:mm:ss").parse(
                                  singleTopUp.createdAt)),
                              style: TextStyle(fontSize: 12.0,
                                  color: Colors.black,
                                  fontWeight: FontWeight.w500)),
                          Text(DateFormat("hh:mm:ss a").format(
                              DateFormat("yyyy-MM-dd HH:mm:ss").parse(
                                  singleTopUp.createdAt)),
                              style: TextStyle(fontSize: 10.0)),
                        ],
                      )
                  )
              ),
              Expanded(
                  child: Center(
                    child: Column(
                      children: <Widget>[
                        Text(singleTopUp.number.replaceFirst(
                            "88", ""),
                            style: TextStyle(fontSize: 10.0)),
                        Text(singleTopUp.type == 0
                            ? "Prepaid"
                            : "Postpaid",
                            style: TextStyle(fontSize: 10.0))
                      ],
                    ),
                  )
              ),
              Expanded(
                  child: Center(
                    child: Text("${singleTopUp.amount} TK",
                        style: TextStyle(fontSize: 12.0,
                            color: Colors.black,
                            fontWeight: FontWeight.w400)),
                  )
              ), Expanded(
                child: Center(
                  child: Column(
                    children: <Widget>[
                      Text(singleTopUp.status == "1000"
                          ? "SUCCESS"
                          : "FAILED", style: TextStyle(fontSize: 10.0)),
                      Text("${singleTopUp.trxnId}",
                          style: TextStyle(fontSize: 7.0))
                    ],
                  ),
                ),
              )
            ],
          ),
        ),
        Divider(
            height: 5.0
        )
      ],
    );
  }


  Widget _buildList() {
    return RefreshIndicator(
      onRefresh: () async {
        // On Refresh.......
      },
      key: _refreshIndicatorKey,
      child: ListView.builder(
        controller: _scrollController,
        itemCount: _hisotories.length + 1, // +1 For ProgressBar
        physics: const AlwaysScrollableScrollPhysics(),
        itemBuilder: (BuildContext context, int index) {
          if (index == _hisotories.length) {
            if (_nextPageUrl != null)
              return _buildProgressIndicator();
          } else {
            return _buildItemView(_hisotories[index]);
          }
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    buildContext = context;
    return Scaffold(
      key: scaffoldKey,
      appBar: AppBar(
        title: Text('Topup History'),
      ),
      body: _isFirstTimeLoading
          ? Center(
        child: CircularProgressIndicator(),
      )
          : _buildList(),
      resizeToAvoidBottomPadding: false,
    );
  }

  @override
  void loadMoreData() {
    if (!_isPaginating) {
      setState(() {
        _isPaginating = true;
      });
    }
    _presenter.getTopUpHistory(_nextPageUrl);
  }

  @override
  void topUpHistoryDidReceived(TopupHistoryData historyData) {
    this._nextPageUrl = historyData.nextPageUrl;
    if (_isPaginating) {
      setState(() {
        _isPaginating = false;
        _hisotories.addAll(historyData.data);
      });
    } else {
      setState(() {
        _isFirstTimeLoading = false;
        _hisotories = historyData.data;
      });
    }
  }

  @override
  void onNetworkCallStarted(String loadingMsg) {
  }

  @override
  void onNetworkCallEnded() {
  }

}