update pagination listener

2024-01-23 17:48:34 +06:30
parent f3f75a80c6
commit 5ec51c31fd
13 changed files with 186 additions and 181 deletions
--- a/lib/domain/entities/pickup.dart
+++ b/lib/domain/entities/pickup.dart
@@ -80,20 +80,20 @@ class Pickup {
    return Pickup(
        id: id,
        pickupDate: _pickupDate.toDate().toLocal(),
-        pickupNumber: map['pickup_number'],
+        pickupNumber: map['pickup_number'] ?? "",
        pickupAddress: _da,
        fromTime: _fromTime?.toDate().toLocal() ?? null,
        toTime: _toTime?.toDate().toLocal() ?? null,
-        staffId: map['pickup_staff_id'],
-        staffName: map['pickup_staff_name'],
-        customerID: map['customer_id'],
-        customerName: map['customer_name'],
+        staffId: map['pickup_staff_id'] ?? "",
+        staffName: map['pickup_staff_name'] ?? "",
+        customerID: map['customer_id'] ?? "",
+        customerName: map['customer_name'] ?? "",
        customerRemark: map['customer_remark'] ?? "",
        completeRemark: map['complete_remark'] ?? "",
-        rescheduleRemark: map['reschedule_remark'],
-        zoneID: map['zone_id'],
-        zoneName: map['zone_name'],
-        status: map['status'],
+        rescheduleRemark: map['reschedule_remark'] ?? "",
+        zoneID: map['zone_id'] ?? "",
+        zoneName: map['zone_name'] ?? "",
+        status: map['status'] ?? "",
        photoUrls: _photoUrls);
  }

--- a/lib/pages/carton/model/carton_model.dart
+++ b/lib/pages/carton/model/carton_model.dart
@@ -81,7 +81,7 @@ class CartonModel extends BaseModel {

  set selectedIndexFilter(int index) {
    _selectedIndexFilter = index;
-    _loadCartonsByFilter(
+    _loadPaginationCartons(
        _selectedIndexFilter == 1 ? "carton_weight" : "user_name");
    notifyListeners();
  }
@@ -109,12 +109,8 @@ class CartonModel extends BaseModel {
  Future<void> _initData() async {
    logout();
    _selectedIndexFilter = 1;
-    cartonsByFilter = PaginatorListener<Carton>(
-        (data, id) => Carton.fromMap(data, id), onChange: () {
-      notifyListeners();
-    }, rowPerLoad: 30, insertNewByListener: true);

-    _loadCartonsByFilter(
+    _loadPaginationCartons(
        _selectedIndexFilter == 1 ? "carton_weight" : "user_name");
  }

@@ -146,30 +142,26 @@ class CartonModel extends BaseModel {
    }
  }

-  Future<void> _loadCartonsByFilter(String orderName) async {
+  _loadPaginationCartons(String orderName) {
    if (user == null || !user!.hasCarton()) return null;
    String path = "/$cartons_collection";

-    try {
-      Query listenerQuery = FirebaseFirestore.instance
-          .collection("$path")
-          .where("carton_type", whereIn: [
-        carton_from_packages,
-        carton_from_cartons
-      ]).where("status", isEqualTo: carton_packed_status);
+    Query col = FirebaseFirestore.instance.collection(path).where("carton_type",
+        whereIn: [
+          carton_from_packages,
+          carton_from_cartons
+        ]).where("status", isEqualTo: carton_packed_status);
+    Query pageQuery = FirebaseFirestore.instance
+        .collection(path)
+        .where("carton_type",
+            whereIn: [carton_from_packages, carton_from_cartons])
+        .where("status", isEqualTo: carton_packed_status)
+        .orderBy(orderName, descending: true);

-      Query pageQuery = FirebaseFirestore.instance
-          .collection("$path")
-          .where("carton_type",
-              whereIn: [carton_from_packages, carton_from_cartons])
-          .where("status", isEqualTo: carton_packed_status)
-          .orderBy(orderName, descending: true);
-
-      cartonsByFilter!
-          .refresh(listeningQuery: listenerQuery, pageQuery: pageQuery);
-    } catch (e) {
-      log.warning("Error!! $e");
-    }
+    cartonsByFilter?.close();
+    cartonsByFilter = PaginatorListener<Carton>(
+        col, pageQuery, (data, id) => Carton.fromMap(data, id),
+        rowPerLoad: 30);
  }

  Paginator? _getDelivered() {
--- a/lib/pages/customer/model/customer_model.dart
+++ b/lib/pages/customer/model/customer_model.dart
@@ -7,8 +7,11 @@ import 'package:fcs/domain/entities/user.dart';
 import 'package:fcs/pages/main/model/base_model.dart';
 import 'package:logging/logging.dart';

+import '../../../pagination/paginator_listener.dart';
+
 class CustomerModel extends BaseModel {
  final log = Logger('CustomerModel');
+  PaginatorListener<User>? getCustomers;

  List<User> customers = [];
  List<User> invitations = [];
@@ -28,8 +31,11 @@ class CustomerModel extends BaseModel {
    if (invitationListener != null) invitationListener!.cancel();
    customers = [];
    invitations = [];
+    getCustomers?.close();
  }

+  
+
  Future<void> inviteUser(String userName, String phoneNumber) {
    return Services.instance.userService.inviteUser(userName, phoneNumber);
  }
--- a/lib/pages/package/model/package_model.dart
+++ b/lib/pages/package/model/package_model.dart
@@ -26,8 +26,8 @@ class PackageModel extends BaseModel {
  set menuSelectedIndex(int index) {
    _menuSelectedIndex = index;

-    _loadPackages(_menuSelectedIndex == 2);
-    _loadCustomerPackages(_menuSelectedIndex == 2);
+    _loadPaginationPackages(_menuSelectedIndex == 2);
+    _loadPaginationCustomerPackages(_menuSelectedIndex == 2);

    notifyListeners();
  }
@@ -41,24 +41,11 @@ class PackageModel extends BaseModel {
  }

  Future<void> _initData() async {
-    logout();
    _menuSelectedIndex = 1;
-    packages = PaginatorListener<Package>(
-        (data, id) => Package.fromMap(data, id), onChange: () {
-      notifyListeners();
-    }, rowPerLoad: 30, insertNewByListener: true);
-    customerPackages = PaginatorListener<Package>(
-        (data, id) => Package.fromMap(data, id), onChange: () {
-      notifyListeners();
-    }, rowPerLoad: 30, insertNewByListener: true);
-    activePackages = PaginatorListener<Package>(
-        (data, id) => Package.fromMap(data, id), onChange: () {
-      notifyListeners();
-    }, rowPerLoad: 30, insertNewByListener: true);

-    _loadPackages(_menuSelectedIndex == 2);
-    _loadCustomerPackages(_menuSelectedIndex == 2);
-    _loadActivePackages();
+    _loadPaginationPackages(_menuSelectedIndex == 2);
+    _loadPaginationCustomerPackages(_menuSelectedIndex == 2);
+    _loadPaginationActivePackages();
  }

  @override
@@ -68,71 +55,68 @@ class PackageModel extends BaseModel {
    if (activePackages != null) activePackages!.close();
  }

-  Future<void> _loadPackages(bool isDelivered) async {
+  _loadPaginationPackages(bool isDelivered) {
    if (user == null) return;
    if (!((user!.hasPackages() ||
        user!.hasReceiving() ||
        user!.hasProcessing()))) return;
    String path = "/$packages_collection";

-    try {
-      Query listenerQuery = FirebaseFirestore.instance
-          .collection(path)
-          .where("is_delivered", isEqualTo: isDelivered);
-      Query pageQuery = FirebaseFirestore.instance
-          .collection(path)
-          .where("is_delivered", isEqualTo: isDelivered);
+    Query col = FirebaseFirestore.instance
+        .collection(path)
+        .where("is_delivered", isEqualTo: isDelivered);
+    Query pageQuery = FirebaseFirestore.instance
+        .collection(path)
+        .where("is_delivered", isEqualTo: isDelivered)
+        .orderBy("update_time", descending: true);

-      pageQuery = pageQuery.orderBy("update_time", descending: true);
-      packages!.refresh(listeningQuery: listenerQuery, pageQuery: pageQuery);
-    } catch (e) {
-      log.warning("Error!! $e");
-    }
+    packages?.close();
+    packages = PaginatorListener<Package>(
+        col, pageQuery, (data, id) => Package.fromMap(data, id),
+        rowPerLoad: 30);
  }

-  Future<void> _loadCustomerPackages(bool isDelivered) async {
+  _loadPaginationCustomerPackages(bool isDelivered) {
    if (user == null) return;
    String path = "/$packages_collection";

-    try {
-      Query listenerQuery = FirebaseFirestore.instance
-          .collection(path)
-          .where("is_delivered", isEqualTo: isDelivered)
-          .where("user_id", isEqualTo: user!.id);
-      Query pageQuery = FirebaseFirestore.instance
-          .collection(path)
-          .where("is_delivered", isEqualTo: isDelivered)
-          .where("user_id", isEqualTo: user!.id)
-          .orderBy("update_time", descending: true);
+    Query col = FirebaseFirestore.instance
+        .collection(path)
+        .where("is_delivered", isEqualTo: isDelivered)
+        .where("user_id", isEqualTo: user!.id);

-      customerPackages!
-          .refresh(listeningQuery: listenerQuery, pageQuery: pageQuery);
-    } catch (e) {
-      log.warning("Error!! $e");
-    }
+    Query pageQuery = FirebaseFirestore.instance
+        .collection(path)
+        .where("is_delivered", isEqualTo: isDelivered)
+        .where("user_id", isEqualTo: user!.id)
+        .orderBy("update_time", descending: true);
+
+    customerPackages?.close();
+    customerPackages = PaginatorListener<Package>(
+        col, pageQuery, (data, id) => Package.fromMap(data, id),
+        rowPerLoad: 30);
  }

-  Future<void> _loadActivePackages() async {
+  _loadPaginationActivePackages() {
    if (user == null) return;
    if (!((user!.hasPackages() ||
        user!.hasReceiving() ||
        user!.hasProcessing()))) return;
    String path = "/$packages_collection";

-    try {
-      Query listenerQuery = FirebaseFirestore.instance
-          .collection(path)
-          .where("is_delivered", isEqualTo: false);
-      Query pageQuery = FirebaseFirestore.instance
-          .collection(path)
-          .where("is_delivered", isEqualTo: false);
+    Query col = FirebaseFirestore.instance
+        .collection(path)
+        .where("is_delivered", isEqualTo: false);

-      pageQuery = pageQuery.orderBy("update_time", descending: true);
-      activePackages!
-          .refresh(listeningQuery: listenerQuery, pageQuery: pageQuery);
-    } catch (e) {
-      log.warning("Error!! $e");
-    }
+    Query pageQuery = FirebaseFirestore.instance
+        .collection(path)
+        .where("is_delivered", isEqualTo: false)
+        .orderBy("update_time", descending: true);
+
+    activePackages?.close();
+    activePackages = PaginatorListener<Package>(
+        col, pageQuery, (data, id) => Package.fromMap(data, id),
+        rowPerLoad: 30);
  }

  Future<Package?> getPackage(String id) async {
--- a/lib/pages/package/package_list.dart
+++ b/lib/pages/package/package_list.dart
@@ -85,11 +85,8 @@ class _PackageListState extends State<PackageList> {
          ),
          body: PaginatorListView<Package>(
            paginatorListener: packages!,
-            rowBuilder: (p) => PackageListRow(
-              key: ValueKey(p.id),
-              package: p,
-              isCustomer: widget.forCustomer,
-            ),
+            rowBuilder: (p) =>
+                PackageListRow(package: p, isCustomer: widget.forCustomer),
            color: primaryColor,
          )),
    );
--- a/lib/pages/pickup/model/pickup_model.dart
+++ b/lib/pages/pickup/model/pickup_model.dart
@@ -27,12 +27,7 @@ class PickupModel extends BaseModel {
  }

  Future<void> _initData() async {
-    logout();
-    pickups = PaginatorListener<Pickup>((data, id) => Pickup.fromMap(data, id),
-        onChange: () {
-      notifyListeners();
-    }, rowPerLoad: 30, insertNewByListener: true);
-    _loadPickups();
+    _loadPaginationPickups();
  }

  @override
@@ -40,20 +35,18 @@ class PickupModel extends BaseModel {
    if (pickups != null) pickups!.close();
  }

-  Future<void> _loadPickups() async {
+  _loadPaginationPickups() {
    if (user == null) return;
    String path = "/$pickup_collection";
+    Query col = FirebaseFirestore.instance.collection(path);
+    Query pageQuery = FirebaseFirestore.instance
+        .collection(path)
+        .orderBy("update_time", descending: true);

-    try {
-      Query listenerQuery = FirebaseFirestore.instance.collection(path);
-      Query pageQuery = FirebaseFirestore.instance
-          .collection(path)
-          .orderBy("update_time", descending: true);
-
-      pickups!.refresh(listeningQuery: listenerQuery, pageQuery: pageQuery);
-    } catch (e) {
-      log.warning("Error!! $e");
-    }
+    pickups?.close();
+    pickups = PaginatorListener<Pickup>(
+        col, pageQuery, (data, id) => Pickup.fromMap(data, id),
+        rowPerLoad: 30);
  }

  Future<void> complete(
--- a/lib/pages/pickup/pickup_list.dart
+++ b/lib/pages/pickup/pickup_list.dart
@@ -65,7 +65,7 @@ class _PickupListState extends State<PickupList> {
          ),
          body: PaginatorListView<Pickup>(
            paginatorListener: pickups!,
-            rowBuilder: (p) => PickupListRow(key: ValueKey(p.id), pickup: p),
+            rowBuilder: (p) => PickupListRow(pickup: p),
            color: primaryColor,
          )),
    );
--- a/lib/pages/processing/processing_list.dart
+++ b/lib/pages/processing/processing_list.dart
@@ -74,10 +74,7 @@ class _ProcessingListState extends State<ProcessingList> {
          ),
          body: PaginatorListView<Package>(
            paginatorListener: packages!,
-            rowBuilder: (p) => ProcessingListRow(
-              key: ValueKey(p.id),
-              package: p,
-            ),
+            rowBuilder: (p) => ProcessingListRow(package: p),
            color: primaryColor,
          )),
    );
--- a/lib/pages/processing_old/processing_list.dart
+++ b/lib/pages/processing_old/processing_list.dart
@@ -65,10 +65,7 @@ class _ProcessingListState extends State<ProcessingList> {
          ),
          body: PaginatorListView<Package>(
            paginatorListener: packages!,
-            rowBuilder: (p) => ProcessingListRow(
-              key: ValueKey(p.id),
-              package: p,
-            ),
+            rowBuilder: (p) => ProcessingListRow(package: p),
            color: primaryColor,
          )),
    );
--- a/lib/pages/receiving/receiving_list.dart
+++ b/lib/pages/receiving/receiving_list.dart
@@ -73,13 +73,9 @@ class _ReceivingListState extends State<ReceivingList> {
            backgroundColor: primaryColor,
          ),
          body: PaginatorListView<Package>(
-            paginatorListener: packages!,
-            rowBuilder: (p) => ReceivingListRow(
-              key: ValueKey(p.id),
-              package: p,
-            ),
-            color: primaryColor,
-          )),
+              paginatorListener: packages!,
+              rowBuilder: (p) => ReceivingListRow(package: p),
+              color: primaryColor)),
    );
  }

--- a/lib/pages/widgets/local_dropdown.dart
+++ b/lib/pages/widgets/local_dropdown.dart
@@ -1,5 +1,4 @@
 import 'package:fcs/helpers/theme.dart';
-import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';

 import 'local_text.dart';
--- a/lib/pagination/paginator_listener.dart
+++ b/lib/pagination/paginator_listener.dart
@@ -1,9 +1,11 @@
 import 'dart:async';

 import 'package:cloud_firestore/cloud_firestore.dart';
-import 'package:fcs/pages/widgets/callbacks.dart';
+import 'package:flutter/foundation.dart';
 import 'package:logging/logging.dart';

+import '../pages/widgets/callbacks.dart';
+
 typedef ToObj = Function(Map<String, dynamic> data, String id);

 /*
@@ -11,7 +13,7 @@ typedef ToObj = Function(Map<String, dynamic> data, String id);
 * and listen to document change based on 'update_time' and 'delete_time' fields
 * of the document
 */
-class PaginatorListener<T> {
+class PaginatorListener<T> extends ChangeNotifier {
  final log = Logger('PaginatorListener');

  List<String> ids = [];
@@ -25,15 +27,18 @@ class PaginatorListener<T> {
  CallBack? onChange;

  StreamSubscription<QuerySnapshot>? listener;
-  Query? listeningQuery;
-  Query? pageQuery;
+  Query listeningQuery;
+  Query pageQuery;
+  bool Function(T obj)? removeOnDataChange;

-  PaginatorListener(this.toObj,
-      {this.onChange, this.rowPerLoad = 10, this.insertNewByListener = false});
+  PaginatorListener(this.listeningQuery, this.pageQuery, this.toObj,
+      {this.rowPerLoad = 10,
+      this.insertNewByListener = true,
+      this.removeOnDataChange}) {
+    refresh();
+  }

-  Future<bool> refresh({Query? listeningQuery, Query? pageQuery}) {
-    this.listeningQuery = listeningQuery ?? this.listeningQuery;
-    this.pageQuery = pageQuery ?? this.pageQuery;
+  Future<bool> refresh() {
    _clearState();
    _initListener();
    return _load();
@@ -45,8 +50,9 @@ class PaginatorListener<T> {
    data = [];
    ended = false;
    isLoading = false;
-    if (listener != null) listener!.cancel();
+    listener?.cancel();
    listener = null;
+    notifyListeners();
  }

  void close() {
@@ -58,26 +64,25 @@ class PaginatorListener<T> {
  final String isDeletedField = 'is_deleted';
  void _initListener() {
    Query _query =
-        listeningQuery!.orderBy(updateTimeField, descending: true).limit(1);
+        listeningQuery.orderBy(updateTimeField, descending: true).limit(1);
    _query
-        .get(GetOptions(source: Source.server))
+        .get(const GetOptions(source: Source.server))
        .then((QuerySnapshot snapshot) {
      int count = snapshot.docs.length;
      int updateTime = 0;
      if (count == 1) {
-        Map<String, dynamic> data =
-            snapshot.docs[0].data()! as Map<String, dynamic>;
-        updateTime = data[updateTimeField];
+        updateTime =
+            (snapshot.docs[0].data() as Map<String, dynamic>)[updateTimeField];
      }

-      Query _queryListener = listeningQuery!
+      Query _queryListener = listeningQuery
          .where(updateTimeField, isGreaterThan: updateTime)
+          // .where(deleteTimeField, isEqualTo: 0)
          .orderBy(updateTimeField, descending: true);

-      if (listener != null) listener!.cancel();
      listener =
          _queryListener.snapshots(includeMetadataChanges: true).listen((qs) {
-        qs.docChanges.forEach((c) {
+        for (var c in qs.docChanges) {
          switch (c.type) {
            case DocumentChangeType.added:
              _update(c.doc.id, c.doc.data() as Map<String, dynamic>);
@@ -91,7 +96,8 @@ class PaginatorListener<T> {
            default:
          }
          if (onChange != null) onChange!();
-        });
+          notifyListeners();
+        }
      });
    });
  }
@@ -104,11 +110,15 @@ class PaginatorListener<T> {
      if ((deleted ?? 0) > 0 || (isDeleted ?? false)) {
        data.removeAt(ids.indexOf(id));
        ids.remove(id);
+      } else if (removeOnDataChange != null && removeOnDataChange!(t)) {
+        data.removeAt(ids.indexOf(id));
+        ids.remove(id);
      } else {
        data.removeAt(ids.indexOf(id));
        data.insert(ids.indexOf(id), t);
      }
    } else if (insertNewByListener) {
+      if (removeOnDataChange != null && removeOnDataChange!(t)) return;
      data.insert(0, t);
      ids.insert(0, id);
    }
@@ -130,37 +140,38 @@ class PaginatorListener<T> {
  }

  Future<bool> loadMore() {
-    return this._load();
+    return _load();
  }

  Future<bool> _load({CallBack? onStarted, CallBack? onFinished}) async {
    if (ended) return ended;
    Query _query =
-        prev != null ? pageQuery!.startAfterDocument(prev!) : pageQuery!;
+        prev != null ? pageQuery.startAfterDocument(prev!) : pageQuery;
    try {
      isLoading = true;
      if (onStarted != null) {
        onStarted();
      }
      if (onChange != null) onChange!();
-      await _query
-          .where(isDeletedField, isEqualTo: false)
+      notifyListeners();
+      QuerySnapshot snapshot = await _query
+          .where(deleteTimeField, isEqualTo: 0)
          .limit(rowPerLoad)
-          .get(GetOptions(source: Source.server))
-          .then((QuerySnapshot snapshot) {
-        int count = snapshot.docs.length;
-        ended = count < rowPerLoad;
-        prev = count > 0 ? snapshot.docs[count - 1] : prev;
-        snapshot.docs.forEach((e) {
-          _add(e.id, e.data() as Map<String, dynamic>);
-        });
-      });
+          .get(const GetOptions(source: Source.server));
+
+      int count = snapshot.docs.length;
+      ended = count < rowPerLoad;
+      prev = count > 0 ? snapshot.docs[count - 1] : prev;
+      for (var e in snapshot.docs) {
+        _add(e.id, e.data() as Map<String, dynamic>);
+      }
    } catch (e) {
      log.warning("Error!! $e");
    } finally {
      isLoading = false;
      if (onFinished != null) onFinished();
      if (onChange != null) onChange!();
+      notifyListeners();
    }
    return ended;
  }
--- a/lib/pagination/paginator_listview.dart
+++ b/lib/pagination/paginator_listview.dart
@@ -1,4 +1,3 @@
-import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';

@@ -6,20 +5,25 @@ import 'paginator_listener.dart';

 typedef RowBuilder = Widget Function(dynamic);
 typedef OnScroll = void Function(bool down);
+typedef OnRemove = Function(dynamic t);

-class PaginatorListView<T> extends StatelessWidget {
+class PaginatorListView<T> extends StatefulWidget {
  final PaginatorListener<T> paginatorListener;
  final RowBuilder rowBuilder;
  final OnScroll? onScroll;
  final ScrollController _scrollController;
  final Color color;
+  final OnRemove? onRemove;
+  final Widget? noMoreData;

  PaginatorListView(
      {Key? key,
      required this.paginatorListener,
      required this.rowBuilder,
      this.onScroll,
-      this.color = Colors.blueAccent})
+      this.color = Colors.blueAccent,
+      this.noMoreData,
+      this.onRemove})
      : _scrollController = ScrollController(),
        super(key: key) {
    _scrollController.addListener(() async {
@@ -35,10 +39,37 @@ class PaginatorListView<T> extends StatelessWidget {
    });
  }

+  @override
+  State<PaginatorListView<T>> createState() => _PaginatorListViewState<T>();
+}
+
+class _PaginatorListViewState<T> extends State<PaginatorListView<T>> {
+  late PaginatorListener<T> _paginatorListener;
+  @override
+  initState() {
+    super.initState();
+    initListener();
+  }
+
+  @override
+  void didUpdateWidget(covariant PaginatorListView<T> oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    initListener();
+  }
+
+  initListener() {
+    _paginatorListener = widget.paginatorListener;
+    widget.paginatorListener.addListener(() {
+      if (mounted) {
+        setState(() {});
+      }
+    });
+  }
+
  @override
  Widget build(BuildContext context) {
-    bool ended = paginatorListener.ended;
-    int count = paginatorListener.data.length;
+    bool ended = _paginatorListener.ended;
+    int count = _paginatorListener.data.length;
    if (ended) count++;

    return Column(
@@ -46,12 +77,12 @@ class PaginatorListView<T> extends StatelessWidget {
        Expanded(
          child: RefreshIndicator(
            onRefresh: () {
-              return paginatorListener.refresh();
+              return _paginatorListener.refresh();
            },
            child: ListView.separated(
                separatorBuilder: (context, index) =>
                    Divider(height: 1, color: Colors.black),
-                controller: _scrollController,
+                controller: widget._scrollController,
                scrollDirection: Axis.vertical,
                physics: const AlwaysScrollableScrollPhysics(),
                shrinkWrap: true,
@@ -60,22 +91,24 @@ class PaginatorListView<T> extends StatelessWidget {
                  if (ended && index == count - 1) {
                    return Padding(
                      padding: const EdgeInsets.all(8.0),
-                      child: Center(child: Text("No more data")),
+                      child: Center(
+                          child:
+                              widget.noMoreData ?? const Text("No more data")),
                    );
                  }
-                  T t = paginatorListener.data[index];
-                  return rowBuilder(t);
+                  T t = _paginatorListener.data[index];
+                  return widget.rowBuilder(t);
                }),
          ),
        ),
-        paginatorListener.isLoading ? _loadingRow() : Container()
+        _paginatorListener.isLoading ? _loadingRow() : Container()
      ],
    );
  }

  Widget _loadingRow() {
    return Container(
-      padding: EdgeInsets.all(8),
+      padding: const EdgeInsets.all(8),
      color: Colors.transparent,
      child: Row(
        mainAxisAlignment: MainAxisAlignment.center,
@@ -83,10 +116,10 @@ class PaginatorListView<T> extends StatelessWidget {
          Column(
            children: [
              CircularProgressIndicator(
-                  valueColor: new AlwaysStoppedAnimation<Color>(color)),
+                  valueColor: AlwaysStoppedAnimation<Color>(widget.color)),
              Text(
                "Loading...",
-                style: TextStyle(color: color),
+                style: TextStyle(color: widget.color),
              )
            ],
          ),