Refactor paginated search widgets

- Implement a base class
- Override specific members

lib/widget/company_list.dart

@@ -5,6 +5,7 @@ import "package:infinite_scroll_pagination/infinite_scroll_pagination.dart";
 
 import "package:inventree/api.dart";
 import "package:inventree/inventree/company.dart";
+import 'package:inventree/inventree/model.dart';
 import "package:inventree/inventree/sentry.dart";
 import "package:inventree/widget/paginator.dart";
 import "package:inventree/widget/refreshable_state.dart";
@@ -56,96 +57,25 @@ class PaginatedCompanyList extends StatefulWidget {
   final Function(int)? onTotalChanged;
 
   @override
-  _CompanyListState createState() => _CompanyListState(filters, onTotalChanged);
+  _CompanyListState createState() => _CompanyListState(filters);
 }
 
-class _CompanyListState extends State<PaginatedCompanyList> {
+class _CompanyListState extends PaginatedSearchState<PaginatedCompanyList> {
 
-  _CompanyListState(this.filters, this.onTotalChanged);
-  
-  static const _pageSize = 25;
-
-  String _searchTerm = "";
-
-  Function(int)? onTotalChanged;
-  
-  final Map<String, String> filters;
-  
-  final PagingController<int, InvenTreeCompany> _pagingController = PagingController(firstPageKey: 0);
-
-  final TextEditingController searchController = TextEditingController();
+  _CompanyListState(Map<String, String> filters) : super(filters);
 
   @override
-  void initState() {
-    _pagingController.addPageRequestListener((pageKey) {
-      _fetchPage(pageKey);
-    });
+  Future<InvenTreePageResponse?> requestPage(int limit, int offset, Map<String, String> params) async {
 
-    super.initState();
+    final page = await InvenTreeCompany().listPaginated(limit, offset, filters: params);
+
+    return page;
   }
 
   @override
-  void dispose() {
-    _pagingController.dispose();
-    super.dispose();
-  }
+  Widget buildItem(BuildContext context, InvenTreeModel model) {
 
-  int resultCount = 0;
-  
-  Future<void> _fetchPage(int pageKey) async {
-    try {
-      Map<String, String> params = filters;
-
-      params["search"] = _searchTerm;
-
-      final page = await InvenTreeCompany().listPaginated(
-          _pageSize, pageKey, filters: params);
-
-      int pageLength = page?.length ?? 0;
-      int pageCount = page?.count ?? 0;
-
-      final isLastPage = pageLength < _pageSize;
-
-      List<InvenTreeCompany> companies = [];
-
-      if (page != null) {
-        for (var result in page.results) {
-          if (result is InvenTreeCompany) {
-            companies.add(result);
-          } else {
-            print(result.jsondata);
-          }
-        }
-      }
-
-      if (isLastPage) {
-        _pagingController.appendLastPage(companies);
-      } else {
-        final int nextPageKey = pageKey + pageLength;
-        _pagingController.appendPage(companies, nextPageKey);
-      }
-
-      if (onTotalChanged != null) {
-        onTotalChanged!(pageCount);
-      }
-
-      setState(() {
-        resultCount = pageCount;
-      });
-    } catch (error, stackTrace) {
-      print("Error! - ${error.toString()}");
-      _pagingController.error = error;
-      
-      sentryReportError(error, stackTrace);
-    }
-  }
-
-  void updateSearchTerm() {
-    _searchTerm = searchController.text;
-    _pagingController.refresh();
-  }
-
-  Widget _buildCompany(BuildContext context, InvenTreeCompany company) {
+    InvenTreeCompany company = model as InvenTreeCompany;
 
     return ListTile(
       title: Text(company.name),
@@ -160,36 +90,4 @@ class _CompanyListState extends State<PaginatedCompanyList> {
       },
     );
   }
-  
-  @override
-  Widget build(BuildContext context) {
-    return Column(
-      mainAxisAlignment: MainAxisAlignment.start,
-      children: [
-        PaginatedSearchWidget(searchController, updateSearchTerm, resultCount),
-        Expanded(
-          child: CustomScrollView(
-            shrinkWrap: true,
-            physics: ClampingScrollPhysics(),
-            scrollDirection: Axis.vertical,
-            slivers: [
-              PagedSliverList.separated(
-                pagingController: _pagingController,
-                builderDelegate: PagedChildBuilderDelegate<InvenTreeCompany>(
-                  itemBuilder: (context, item, index) {
-                    return _buildCompany(context, item);
-                  },
-                  noItemsFoundIndicatorBuilder: (context) {
-                    return NoResultsWidget(L10().companyNoResults);
-                  }
-                ),
-                separatorBuilder: (context, index) => const Divider(height: 1),
-              )
-            ],
-          )
-        )
-      ],
-    );
-  }
-  
 }

lib/widget/paginator.dart

@@ -1,8 +1,147 @@
 import "package:flutter/material.dart";
 import "package:font_awesome_flutter/font_awesome_flutter.dart";
+import 'package:infinite_scroll_pagination/infinite_scroll_pagination.dart';
+import 'package:inventree/inventree/model.dart';
+import 'package:inventree/inventree/sentry.dart';
 import "package:inventree/l10.dart";
 
 
+class PaginatedSearchState<T extends StatefulWidget> extends State<T> {
+
+  PaginatedSearchState(this.filters);
+
+  final Map<String, String> filters;
+
+  static const _pageSize = 25;
+
+  // Search query term
+  String searchTerm = "";
+
+  int resultCount = 0;
+
+  // Text controller
+  final TextEditingController searchController = TextEditingController();
+
+  // Pagination controller
+  final PagingController<int, InvenTreeModel> _pagingController = PagingController(firstPageKey: 0);
+
+  @override
+  void initState() {
+    _pagingController.addPageRequestListener((pageKey) {
+      _fetchPage(pageKey);
+    });
+
+    super.initState();
+  }
+
+  @override
+  void dispose() {
+    _pagingController.dispose();
+    super.dispose();
+  }
+
+  Future<InvenTreePageResponse?> requestPage(int limit, int offset, Map<String, String> params) async {
+
+    print("Blank request page");
+    // Default implementation returns null - must be overridden
+    return null;
+  }
+
+  Future<void> _fetchPage(int pageKey) async {
+    try {
+      Map<String, String> params = filters;
+
+      params["search"] = "${searchTerm}";
+
+      final page = await requestPage(
+        _pageSize,
+        pageKey,
+        params
+      );
+
+      int pageLength = page?.length ?? 0;
+      int pageCount = page?.count ?? 0;
+
+      final isLastPage = pageLength < _pageSize;
+
+      List<InvenTreeModel> items = [];
+
+      if (page != null) {
+        for (var result in page.results) {
+          if (result is InvenTreeModel) {
+            items.add(result);
+          }
+        }
+      }
+
+      if (isLastPage) {
+        _pagingController.appendLastPage(items);
+      } else {
+        final int nextPageKey = pageKey + pageLength;
+        _pagingController.appendPage(items, nextPageKey);
+      }
+
+      setState(() {
+        resultCount = pageCount;
+      });
+    } catch (error, stackTrace) {
+      _pagingController.error = error;
+
+      sentryReportError(error, stackTrace);
+    }
+  }
+
+  void updateSearchTerm() {
+    searchTerm = searchController.text;
+    _pagingController.refresh();
+  }
+
+  Widget buildItem(BuildContext context, InvenTreeModel item) {
+
+    // This method must be overridden by the child class
+    return ListTile(
+      title: Text("*** UNIMPLEMENTED ***"),
+      subtitle: Text("*** buildItem() is unimplemented for this widget!"),
+    );
+  }
+
+  String get noResultsText => L10().noResults;
+
+  @override
+  Widget build (BuildContext context) {
+    return Column(
+        mainAxisAlignment: MainAxisAlignment.start,
+        children: [
+          PaginatedSearchWidget(searchController, updateSearchTerm, resultCount),
+          Expanded(
+              child: CustomScrollView(
+                  shrinkWrap: true,
+                  physics: ClampingScrollPhysics(),
+                  scrollDirection: Axis.vertical,
+                  slivers: <Widget>[
+                    // TODO - Search input
+                    PagedSliverList.separated(
+                      pagingController: _pagingController,
+                      builderDelegate: PagedChildBuilderDelegate<InvenTreeModel>(
+                          itemBuilder: (context, item, index) {
+                            return buildItem(context, item);
+                          },
+                          noItemsFoundIndicatorBuilder: (context) {
+                            return NoResultsWidget(noResultsText);
+                          }
+                      ),
+                      separatorBuilder: (context, item) => const Divider(height: 1),
+                    )
+                  ]
+              )
+          )
+        ]
+    );
+  }
+
+}
+
+
 class PaginatedSearchWidget extends StatelessWidget {
 
   const PaginatedSearchWidget(this.controller, this.onChanged, this.results);

lib/widget/part_list.dart

@@ -1,14 +1,15 @@
-import 'package:flutter/material.dart';
-import 'package:infinite_scroll_pagination/infinite_scroll_pagination.dart';
-import 'package:inventree/inventree/part.dart';
-import 'package:inventree/inventree/sentry.dart';
-import 'package:inventree/widget/paginator.dart';
-import 'package:inventree/widget/part_detail.dart';
-import 'package:inventree/widget/refreshable_state.dart';
+import "package:flutter/material.dart";
+import "package:infinite_scroll_pagination/infinite_scroll_pagination.dart";
+import 'package:inventree/inventree/model.dart';
+import "package:inventree/inventree/part.dart";
+import "package:inventree/inventree/sentry.dart";
+import "package:inventree/widget/paginator.dart";
+import "package:inventree/widget/part_detail.dart";
+import "package:inventree/widget/refreshable_state.dart";
 
-import '../api.dart';
-import '../app_settings.dart';
-import '../l10.dart';
+import "package:inventree/api.dart";
+import "package:inventree/app_settings.dart";
+import "package:inventree/l10.dart";
 
 
 class PartList extends StatefulWidget {
@@ -52,86 +53,21 @@ class PaginatedPartList extends StatefulWidget {
 }
 
 
-class _PaginatedPartListState extends State<PaginatedPartList> {
+class _PaginatedPartListState extends PaginatedSearchState<PaginatedPartList> {
 
-  _PaginatedPartListState(this.filters, this.onTotalChanged);
-
-  static const _pageSize = 25;
-
-  String _searchTerm = "";
+  _PaginatedPartListState(Map<String, String> filters, this.onTotalChanged) : super(filters);
 
   Function(int)? onTotalChanged;
 
-  final Map<String, String> filters;
-
-  final PagingController<int, InvenTreePart> _pagingController = PagingController(firstPageKey: 0);
-
   @override
-  void initState() {
-    _pagingController.addPageRequestListener((pageKey) {
-      _fetchPage(pageKey);
-    });
-
-    super.initState();
-  }
-
-  @override
-  void dispose() {
-    _pagingController.dispose();
-    super.dispose();
-  }
-
-  int resultCount = 0;
-
-  Future<void> _fetchPage(int pageKey) async {
-    try {
-
-      Map<String, String> params = filters;
-
-      params["search"] = _searchTerm;
-
+  Future<InvenTreePageResponse?> requestPage(int limit, int offset, Map<String, String> params) async {
     final bool cascade = await InvenTreeSettingsManager().getBool("partSubcategory", true);
 
     params["cascade"] = "${cascade}";
 
-      final page = await InvenTreePart().listPaginated(_pageSize, pageKey, filters: params);
-      int pageLength = page?.length ?? 0;
-      int pageCount = page?.count ?? 0;
+    final page = await InvenTreePart().listPaginated(limit, offset, filters: params);
 
-      final isLastPage = pageLength < _pageSize;
-
-      // Construct a list of part objects
-      List<InvenTreePart> parts = [];
-
-      if (page != null) {
-        for (var result in page.results) {
-          if (result is InvenTreePart) {
-            parts.add(result);
-          }
-        }
-      }
-
-      if (isLastPage) {
-        _pagingController.appendLastPage(parts);
-      } else {
-        final int nextPageKey = pageKey + pageLength;
-        _pagingController.appendPage(parts, nextPageKey);
-      }
-
-      if (onTotalChanged != null) {
-        onTotalChanged!(pageCount);
-      }
-
-      setState(() {
-        resultCount = pageCount;
-      });
-
-    } catch (error, stackTrace) {
-      print("Error! - ${error.toString()}");
-      _pagingController.error = error;
-
-      sentryReportError(error, stackTrace);
-    }
+    return page;
   }
 
   void _openPart(BuildContext context, int pk) {
@@ -144,7 +80,11 @@ class _PaginatedPartListState extends State<PaginatedPartList> {
     });
   }
 
-  Widget _buildPart(BuildContext context, InvenTreePart part) {
+  @override
+  Widget buildItem(BuildContext context, InvenTreeModel model) {
+
+    InvenTreePart part = model as InvenTreePart;
+
     return ListTile(
       title: Text(part.fullname),
       subtitle: Text("${part.description}"),
@@ -159,43 +99,4 @@ class _PaginatedPartListState extends State<PaginatedPartList> {
       },
     );
   }
-
-  final TextEditingController searchController = TextEditingController();
-
-  void updateSearchTerm() {
-
-    _searchTerm = searchController.text;
-    _pagingController.refresh();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return Column(
-      mainAxisAlignment: MainAxisAlignment.start,
-      children: [
-        PaginatedSearchWidget(searchController, updateSearchTerm, resultCount),
-        Expanded(
-            child: CustomScrollView(
-              shrinkWrap: true,
-              physics: ClampingScrollPhysics(),
-              scrollDirection: Axis.vertical,
-              slivers: [
-                PagedSliverList.separated(
-                  pagingController: _pagingController,
-                  builderDelegate: PagedChildBuilderDelegate<InvenTreePart>(
-                    itemBuilder: (context, item, index) {
-                      return _buildPart(context, item);
-                    },
-                    noItemsFoundIndicatorBuilder: (context) {
-                      return NoResultsWidget(L10().partNoResults);
-                    },
-                  ),
-                  separatorBuilder: (context, index) => const Divider(height: 1),
-                )
-              ],
-            )
-        )
-      ],
-    );
-  }
 }

lib/widget/purchase_order_list.dart

@@ -3,6 +3,7 @@ import "package:flutter/material.dart";
 import "package:infinite_scroll_pagination/infinite_scroll_pagination.dart";
 
 import "package:inventree/inventree/company.dart";
+import 'package:inventree/inventree/model.dart';
 import "package:inventree/inventree/sentry.dart";
 import "package:inventree/widget/paginator.dart";
 import "package:inventree/widget/purchase_order_detail.dart";
@@ -43,117 +44,35 @@ class _PurchaseOrderListWidgetState extends RefreshableState<PurchaseOrderListWi
 
 class PaginatedPurchaseOrderList extends StatefulWidget {
 
-  const PaginatedPurchaseOrderList(this.filters, {this.onTotalChanged});
+  const PaginatedPurchaseOrderList(this.filters);
 
   final Map<String, String> filters;
 
-  final Function(int)? onTotalChanged;
-
   @override
-  _PaginatedPurchaseOrderListState createState() => _PaginatedPurchaseOrderListState(filters, onTotalChanged);
+  _PaginatedPurchaseOrderListState createState() => _PaginatedPurchaseOrderListState(filters);
 
 }
 
 
-class _PaginatedPurchaseOrderListState extends State<PaginatedPurchaseOrderList> {
+class _PaginatedPurchaseOrderListState extends PaginatedSearchState<PaginatedPurchaseOrderList> {
 
-  _PaginatedPurchaseOrderListState(this.filters, this.onTotalChanged);
-
-  static const _pageSize = 25;
-
-  String _searchTerm = "";
-
-  Function(int)? onTotalChanged;
-
-  final Map<String, String> filters;
-
-  final PagingController<int, InvenTreePurchaseOrder> _pagingController = PagingController(firstPageKey: 0);
-
-  final TextEditingController searchController = TextEditingController();
+  _PaginatedPurchaseOrderListState(Map<String, String> filters) : super(filters);
 
   @override
-  void initState() {
-    _pagingController.addPageRequestListener((pageKey) {
-      _fetchPage(pageKey);
-    });
+  Future<InvenTreePageResponse?> requestPage(int limit, int offset, Map<String, String> params) async {
 
-    super.initState();
-  }
-
-  @override
-  void dispose() {
-    _pagingController.dispose();
-    super.dispose();
-  }
-
-  int resultCount = 0;
-
-  Future<void> _fetchPage(int pageKey) async {
-    try {
-      Map<String, String> params = {};
-
-      params["search"] = _searchTerm;
-
-      // Only return results for open purchase orders
     params["outstanding"] = "true";
 
-      // Copy across provided filters
-      for (String key in filters.keys) {
-        params[key] = filters[key] ?? "";
+    final page = await InvenTreePurchaseOrder().listPaginated(limit, offset, filters: params);
+
+    return page;
+
   }
 
-      final page = await InvenTreePurchaseOrder().listPaginated(
-        _pageSize,
-        pageKey,
-        filters: params
-      );
+  @override
+  Widget buildItem(BuildContext context, InvenTreeModel model) {
 
-      int pageLength = page?.length ?? 0;
-      int pageCount = page?.count ?? 0;
-
-      final isLastPage = pageLength < _pageSize;
-
-      List<InvenTreePurchaseOrder> orders = [];
-
-      if (page != null) {
-        for (var result in page.results) {
-          if (result is InvenTreePurchaseOrder) {
-            orders.add(result);
-          } else {
-            print("Result is not valid PurchaseOrder:");
-            print(result.jsondata);
-          }
-        }
-      }
-
-      if (isLastPage) {
-        _pagingController.appendLastPage(orders);
-      } else {
-        final int nextPageKey = pageKey + pageLength;
-        _pagingController.appendPage(orders, nextPageKey);
-      }
-
-      if (onTotalChanged != null) {
-        onTotalChanged!(pageCount);
-      }
-
-      setState(() {
-        resultCount = pageCount;
-      });
-    } catch (error, stackTrace) {
-      print("Error! - ${error.toString()}");
-      _pagingController.error = error;
-
-      sentryReportError(error, stackTrace);
-    }
-  }
-
-  void updateSearchTerm() {
-    _searchTerm = searchController.text;
-    _pagingController.refresh();
-  }
-
-  Widget _buildOrder(BuildContext context, InvenTreePurchaseOrder order) {
+    InvenTreePurchaseOrder order = model as InvenTreePurchaseOrder;
 
     InvenTreeCompany? supplier = order.supplier;
 
@@ -176,35 +95,4 @@ class _PaginatedPurchaseOrderListState extends State<PaginatedPurchaseOrderList>
       },
     );
   }
-
-  @override
-  Widget build(BuildContext context) {
-    return Column(
-      mainAxisAlignment: MainAxisAlignment.start,
-      children: [
-        PaginatedSearchWidget(searchController, updateSearchTerm, resultCount),
-        Expanded(
-            child: CustomScrollView(
-              shrinkWrap: true,
-              physics: ClampingScrollPhysics(),
-              scrollDirection: Axis.vertical,
-              slivers: [
-                PagedSliverList.separated(
-                  pagingController: _pagingController,
-                  builderDelegate: PagedChildBuilderDelegate<InvenTreePurchaseOrder>(
-                      itemBuilder: (context, item, index) {
-                        return _buildOrder(context, item);
-                      },
-                      noItemsFoundIndicatorBuilder: (context) {
-                        return NoResultsWidget(L10().companyNoResults);
-                      }
-                  ),
-                  separatorBuilder: (context, index) => const Divider(height: 1),
-                )
-              ],
-            )
-        )
-      ],
-    );
-  }
 }

lib/widget/stock_list.dart

@@ -2,6 +2,7 @@
 import "package:flutter/cupertino.dart";
 import "package:flutter/material.dart";
 import "package:infinite_scroll_pagination/infinite_scroll_pagination.dart";
+import 'package:inventree/inventree/model.dart';
 import "package:inventree/inventree/sentry.dart";
 import "package:inventree/inventree/stock.dart";
 import "package:inventree/widget/paginator.dart";
@@ -51,84 +52,25 @@ class PaginatedStockItemList extends StatefulWidget {
 }
 
 
-class _PaginatedStockItemListState extends State<PaginatedStockItemList> {
+class _PaginatedStockItemListState extends PaginatedSearchState<PaginatedStockItemList> {
 
-  _PaginatedStockItemListState(this.filters);
-
-  static const _pageSize = 25;
-
-  String _searchTerm = "";
-
-  final Map<String, String> filters;
-
-  final PagingController<int, InvenTreeStockItem> _pagingController = PagingController(firstPageKey: 0);
+  _PaginatedStockItemListState(Map<String, String> filters) : super(filters);
 
   @override
-  String getAppbarTitle(BuildContext context) => L10().stockItems;
-
-  @override
-  void initState() {
-    _pagingController.addPageRequestListener((pageKey) {
-      _fetchPage(pageKey);
-    });
-
-    super.initState();
-  }
-
-  @override
-  void dispose() {
-    _pagingController.dispose();
-    super.dispose();
-  }
-
-  int resultCount = 0;
-
-  Future<void> _fetchPage(int pageKey) async {
-    try {
-
-      Map<String, String> params = filters;
-
-      params["search"] = "${_searchTerm}";
+  Future<InvenTreePageResponse?> requestPage(int limit, int offset, Map<String, String> params) async {
 
     // Do we include stock items from sub-locations?
     final bool cascade = await InvenTreeSettingsManager().getBool("stockSublocation", true);
 
     params["cascade"] = "${cascade}";
 
-      final page = await InvenTreeStockItem().listPaginated(_pageSize, pageKey, filters: params);
+    final page = await InvenTreeStockItem().listPaginated(
+      limit,
+      offset,
+      filters: params
+    );
 
-      int pageLength = page?.length ?? 0;
-      int pageCount = page?.count ?? 0;
-
-      final isLastPage = pageLength < _pageSize;
-
-      // Construct a list of stock item objects
-      List<InvenTreeStockItem> items = [];
-
-      if (page != null) {
-        for (var result in page.results) {
-          if (result is InvenTreeStockItem) {
-            items.add(result);
-          }
-        }
-      }
-
-      if (isLastPage) {
-        _pagingController.appendLastPage(items);
-      } else {
-        final int nextPageKey = pageKey + pageLength;
-        _pagingController.appendPage(items, nextPageKey);
-      }
-
-      setState(() {
-        resultCount = pageCount;
-      });
-
-    } catch (error, stackTrace) {
-      _pagingController.error = error;
-
-      sentryReportError(error, stackTrace);
-    }
+    return page;
   }
 
   void _openItem(BuildContext context, int pk) {
@@ -139,7 +81,11 @@ class _PaginatedStockItemListState extends State<PaginatedStockItemList> {
     });
   }
 
-  Widget _buildItem(BuildContext context, InvenTreeStockItem item) {
+  @override
+  Widget buildItem(BuildContext context, InvenTreeModel model) {
+
+    InvenTreeStockItem item = model as InvenTreeStockItem;
+
     return ListTile(
       title: Text("${item.partName}"),
       subtitle: Text("${item.locationPathString}"),
@@ -159,43 +105,4 @@ class _PaginatedStockItemListState extends State<PaginatedStockItemList> {
       },
     );
   }
-
-  final TextEditingController searchController = TextEditingController();
-
-  void updateSearchTerm() {
-    _searchTerm = searchController.text;
-    _pagingController.refresh();
-  }
-
-  @override
-  Widget build (BuildContext context) {
-    return Column(
-        mainAxisAlignment: MainAxisAlignment.start,
-        children: [
-          PaginatedSearchWidget(searchController, updateSearchTerm, resultCount),
-          Expanded(
-              child: CustomScrollView(
-                  shrinkWrap: true,
-                  physics: ClampingScrollPhysics(),
-                  scrollDirection: Axis.vertical,
-                  slivers: <Widget>[
-                    // TODO - Search input
-                    PagedSliverList.separated(
-                      pagingController: _pagingController,
-                      builderDelegate: PagedChildBuilderDelegate<InvenTreeStockItem>(
-                          itemBuilder: (context, item, index) {
-                            return _buildItem(context, item);
-                          },
-                          noItemsFoundIndicatorBuilder: (context) {
-                            return NoResultsWidget("No stock items found");
-                          }
-                      ),
-                      separatorBuilder: (context, item) => const Divider(height: 1),
-                    )
-                  ]
-              )
-          )
-        ]
-    );
-  }
 }