add pagination for pages

lib/pages/fcs_shipment/fcs_shipment_list.dart

@@ -4,10 +4,12 @@ import 'package:fcs/pages/widgets/local_popup_menu_button.dart';
 import 'package:fcs/pages/widgets/local_popupmenu.dart';
 import 'package:fcs/pages/widgets/local_text.dart';
 import 'package:fcs/pages/widgets/progress.dart';
+import 'package:fcs/pagination/paginator_listview.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
+import '../../domain/entities/fcs_shipment.dart';
 import 'fcs_shipment_editor.dart';
 import 'fcs_shipment_list_row.dart';
 
@@ -18,18 +20,21 @@ class FcsShipmentList extends StatefulWidget {
 
 class _FcsShipmentListState extends State<FcsShipmentList> {
   bool _isLoading = false;
-  var _controller = ScrollController();
+  int _selectedIndex = 1;
 
   @override
   void initState() {
     super.initState();
+    _init();
+  }
 
-    _controller.addListener(() async {
-      if (_controller.position.pixels == _controller.position.maxScrollExtent) {
-        Provider.of<FcsShipmentModel>(context, listen: false).loadMore();
-      }
-    });
-    Provider.of<FcsShipmentModel>(context, listen: false).initData();
+  _init() {
+    var model = context.read<FcsShipmentModel>();
+    _selectedIndex = model.selectedIndex;
+    model.loadFcsShipments(_selectedIndex);
+    if (mounted) {
+      setState(() {});
+    }
   }
 
   @override
@@ -47,9 +52,12 @@ class _FcsShipmentListState extends State<FcsShipmentList> {
             textKey: "FCSshipment.popupmenu.shipped",
             selected: shipmentModel.selectedIndex == 2)
       ],
-      popupMenuCallback: (p) => this.setState(() {
-        shipmentModel.selectedIndex = p.id;
-      }),
+      popupMenuCallback: (p) {
+        setState(() {
+          _selectedIndex = p.id;
+        });
+        context.read<FcsShipmentModel>().onChanged(_selectedIndex);
+      },
     );
 
     return LocalProgress(
@@ -67,51 +75,17 @@ class _FcsShipmentListState extends State<FcsShipmentList> {
               actions: [popupMenu],
             ),
             floatingActionButton: FloatingActionButton.extended(
-              onPressed: () {
-                _newShipment();
-              },
-              icon: Icon(Icons.add),
-              label: LocalText(context, "FCSshipment.add", color: Colors.white),
-              backgroundColor: primaryColor,
-            ),
-            body: Column(
-              children: <Widget>[
-                Expanded(
-                  child: RefreshIndicator(
-                    child: ListView.separated(
-                        physics: AlwaysScrollableScrollPhysics(),
-                        controller: _controller,
-                        separatorBuilder: (context, index) => Divider(
-                              color: Colors.black,
-                              height: 1,
-                            ),
-                        scrollDirection: Axis.vertical,
-                        shrinkWrap: true,
-                        itemCount: shipmentModel.fcsShipments.length,
-                        itemBuilder: (BuildContext context, int index) {
-                          return FcsShipmentListRow(
-                              key: ValueKey(
-                                  shipmentModel.fcsShipments[index].id),
-                              shipment: shipmentModel.fcsShipments[index]);
-                        }),
-                    onRefresh: () => shipmentModel.refresh(),
-                  ),
-                ),
-                shipmentModel.isLoading
-                    ? Container(
-                        padding: EdgeInsets.all(8),
-                        color: primaryColor,
-                        child: Row(
-                          mainAxisAlignment: MainAxisAlignment.center,
-                          children: [
-                            Text("Loading...",
-                                style: TextStyle(color: Colors.white)),
-                          ],
-                        ),
-                      )
-                    : Container(),
-              ],
-            )));
+                onPressed: () {
+                  _newShipment();
+                },
+                icon: Icon(Icons.add),
+                label:
+                    LocalText(context, "FCSshipment.add", color: Colors.white),
+                backgroundColor: primaryColor),
+            body: PaginatorListView<FcsShipment>(
+                paginatorListener: shipmentModel.fcsShipments!,
+                rowBuilder: (p) => FcsShipmentListRow(shipment: p),
+                color: primaryColor)));
   }
 
   _newShipment() {

lib/pages/fcs_shipment/model/fcs_shipment_model.dart

@@ -4,100 +4,48 @@ import 'package:cloud_firestore/cloud_firestore.dart';
 import 'package:fcs/data/services/services.dart';
 import 'package:fcs/domain/constants.dart';
 import 'package:fcs/domain/entities/fcs_shipment.dart';
-import 'package:fcs/helpers/paginator.dart';
 import 'package:fcs/pages/main/model/base_model.dart';
 import 'package:logging/logging.dart';
 
+import '../../../pagination/paginator_listener.dart';
+
 class FcsShipmentModel extends BaseModel {
   final log = Logger('FcsShipmentModel');
-
-  StreamSubscription<QuerySnapshot>? listener;
-  List<FcsShipment> _fcsShipments = [];
-  List<FcsShipment> get fcsShipments => _selectedIndex == 1
-      ? _fcsShipments
-      : List<FcsShipment>.from(_shipped!.values);
-
-  Paginator? _shipped;
+  PaginatorListener<FcsShipment>? fcsShipments;
   bool isLoading = false;
-  int _selectedIndex = 1;
-  set selectedIndex(int index) {
-    _selectedIndex = index;
+  int selectedIndex = 1;
+
+  onChanged(int index) {
+    selectedIndex = index;
+    loadFcsShipments(selectedIndex);
     notifyListeners();
   }
 
-  int get selectedIndex => _selectedIndex;
-
-  @override
-  void privilegeChanged() {
-    super.privilegeChanged();
-    _loadFcsShipments();
-  }
-
-  initData() {
-    _selectedIndex = 1;
-    _loadFcsShipments();
-
-    if (_shipped != null) _shipped!.close();
-    _shipped = _getShipped();
-    _shipped!.load();
-  }
-
-  Future<void> _loadFcsShipments() async {
+  loadFcsShipments(int index) {
     if (user == null || !user!.hasFcsShipments()) return;
-    String path = "/$fcs_shipment_collection/";
-    if (listener != null) listener!.cancel();
-    _fcsShipments = [];
-    try {
-      listener = FirebaseFirestore.instance
-          .collection("$path")
-          .where("status", isEqualTo: fcs_shipment_confirmed_status)
-          .where("is_deleted", isEqualTo: false)
-          .orderBy("shipment_number", descending: true)
-          .snapshots()
-          .listen((QuerySnapshot snapshot) {
-        _fcsShipments.clear();
-        _fcsShipments = snapshot.docs.map((documentSnapshot) {
-          var s = FcsShipment.fromMap(
-              documentSnapshot.data() as Map<String, dynamic>,
-              documentSnapshot.id);
-          return s;
-        }).toList();
-        notifyListeners();
-      });
-    } catch (e) {
-      log.warning("Error!! $e");
+
+    String path = "/$fcs_shipment_collection";
+    Query col = FirebaseFirestore.instance.collection(path);
+    Query pageQuery = FirebaseFirestore.instance.collection(path);
+
+    if (index == 1) {
+      col = col.where("status", isEqualTo: fcs_shipment_confirmed_status);
+      pageQuery =
+          pageQuery.where("status", isEqualTo: fcs_shipment_confirmed_status);
     }
-  }
 
-  Paginator _getShipped() {
-    if (user == null || !user!.hasFcsShipments()) throw "No Privilege";
+    if (index == 2) {
+      col = col.where("status", isEqualTo: fcs_shipment_shipped_status);
+      pageQuery =
+          pageQuery.where("status", isEqualTo: fcs_shipment_shipped_status);
+    }
 
-    var pageQuery = FirebaseFirestore.instance
-        .collection("/$fcs_shipment_collection")
-        .where("status", isEqualTo: fcs_shipment_shipped_status)
-        .where("is_deleted", isEqualTo: false)
-        .orderBy("shipment_number", descending: true);
-    var paginator = new Paginator(pageQuery, rowPerLoad: 20, toObj: (data, id) {
-      return FcsShipment.fromMap(data, id);
-    });
-    return paginator;
-  }
+    pageQuery = pageQuery.orderBy("shipment_number", descending: true);
 
-  Future<void> loadMore() async {
-    if (_shipped!.ended || _selectedIndex == 1) return;
-    isLoading = true;
-    notifyListeners();
-    await _shipped!.load(onFinished: () {
-      isLoading = false;
-      notifyListeners();
-    });
-  }
-
-  Future<void> refresh() async {
-    if (_selectedIndex == 1) return;
-    await _shipped!.refresh(onFinished: () {
-      notifyListeners();
-    });
+    fcsShipments?.close();
+    fcsShipments = PaginatorListener<FcsShipment>(
+        col, pageQuery, (data, id) => FcsShipment.fromMap(data, id),
+        rowPerLoad: 30);
   }
 
   Future<List<FcsShipment>> getActiveFcsShipments() async {
@@ -157,9 +105,7 @@ class FcsShipmentModel extends BaseModel {
 
   @override
   logout() async {
-    if (listener != null) await listener!.cancel();
-    if (_shipped != null) _shipped!.close();
-    _fcsShipments = [];
+    fcsShipments?.close();
   }
 
   Future<void> create(FcsShipment fcsShipment) {