Better fix for the issue #23

letsar · Jan 10, 2019 · a8c2ffa · a8c2ffa
1 parent 7c1e17e
commit a8c2ffa
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.2.7
+### Fixed
+* Better fix for the bug where items are built only once.
+
 ## 0.2.6
 ### Fixed
 * Fix a bug where items are built only once.

diff --git a/README.md b/README.md
@@ -28,7 +28,7 @@ In the `pubspec.yaml` of your flutter project, add the following dependency:
 ```yaml
 dependencies:
   ...
-  flutter_staggered_grid_view: "^0.2.6"
+  flutter_staggered_grid_view: "^0.2.7"
 ```
 
 In your library add the following import:

diff --git a/example/lib/main_issue_21.dart b/example/lib/main_issue_21.dart
@@ -1,152 +1,89 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_staggered_grid_view/flutter_staggered_grid_view.dart';
 
-class DeviceTypeList {
-  String deviceTypeName = 'test';
-}
-
-class DeviceTypeItem extends StatefulWidget {
-  final List<DeviceTypeList> deviceTypes;
-  final Function onSelected;
-
-  DeviceTypeItem(this.deviceTypes, this.onSelected);
+void main() => runApp(MyApp());
 
+class MyApp extends StatelessWidget {
   @override
-  _DeviceTypeItemState createState() => _DeviceTypeItemState();
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'StaggeredGridView Demo',
+      theme: ThemeData(
+        primarySwatch: Colors.blue,
+      ),
+      home: MyScreen(),
+    );
+  }
 }
 
-class _DeviceTypeItemState extends State<DeviceTypeItem> {
-  int _selectIndex = -1;
+class MyScreen extends StatefulWidget {
+  @override
+  _MyScreenState createState() => new _MyScreenState();
+}
 
-  _DeviceTypeItemState();
+class _MyScreenState extends State<MyScreen> {
+  int _count = 0;
 
-  _selectDevice(int index) {
-    setState(() {
-      _selectIndex = index;
-    });
-//    onSelected(deviceTypes[_selectIndex].deviceTypeName);
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: StaggeredTest(_count, _count),
+      floatingActionButton: FloatingActionButton(
+        child: Icon(Icons.add),
+        onPressed: () {
+          setState(() {
+            _count++;
+          });
+        },
+      ),
+    );
   }
+}
 
-  _tmpData() {
-    return List.generate(
-        10,
-        (int index) => GestureDetector(
-              child: Container(
-                child: Text(widget.deviceTypes[0].deviceTypeName),
-                color: _selectIndex == index ? Colors.blue : Colors.brown,
-                padding: EdgeInsets.only(top: 4, bottom: 4),
-                alignment: Alignment.center,
-              ),
-              onTap: () => _selectDevice(index),
-            ));
-  }
+class GridTest extends StatelessWidget {
+  GridTest(this.count, this.value);
+  final int count;
+  final int value;
 
   @override
   Widget build(BuildContext context) {
-    return Container(
-      padding: EdgeInsets.all(12),
-//      child: GridView.count(
-//        crossAxisCount: 3,
-//        children: _tmpData(),
-//        shrinkWrap: true,
-//      ),
-
-      child: StaggeredGridView.count(
+    return GridView.builder(
+      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
         crossAxisCount: 3,
-        children: _tmpData(),
-        staggeredTiles: List.generate(10, (int index) => StaggeredTile.fit(1)),
-        shrinkWrap: true,
+        crossAxisSpacing: 2,
+        mainAxisSpacing: 2,
       ),
+      itemCount: count,
+      itemBuilder: (context, index) {
+        return Container(
+          color: Colors.blue,
+          child: Text('$value'),
+        );
+      },
     );
   }
 }
 
-// import 'package:flutter/material.dart';
-// import 'package:flutter_staggered_grid_view/flutter_staggered_grid_view.dart';
-
-// void main() => runApp(MyApp());
-
-// class MyApp extends StatelessWidget {
-//   @override
-//   Widget build(BuildContext context) {
-//     return MaterialApp(
-//       title: 'StaggeredGridView Demo',
-//       theme: ThemeData(
-//         primarySwatch: Colors.blue,
-//       ),
-//       home: MyScreen(),
-//     );
-//   }
-// }
-
-// class MyScreen extends StatefulWidget {
-//   @override
-//   _MyScreenState createState() => new _MyScreenState();
-// }
-
-// class _MyScreenState extends State<MyScreen> {
-//   int _count = 0;
-
-//   @override
-//   Widget build(BuildContext context) {
-//     return Scaffold(
-//       body: GridTest(_count, _count),
-//       floatingActionButton: FloatingActionButton(
-//         child: Icon(Icons.add),
-//         onPressed: () {
-//           setState(() {
-//             _count++;
-//           });
-//         },
-//       ),
-//     );
-//   }
-// }
-
-// class GridTest extends StatelessWidget {
-//   GridTest(this.count, this.value);
-//   final int count;
-//   final int value;
+class StaggeredTest extends StatelessWidget {
+  StaggeredTest(this.count, this.value);
+  final int count;
+  final int value;
 
-//   @override
-//   Widget build(BuildContext context) {
-//     return GridView.builder(
-//       gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
-//         crossAxisCount: 3,
-//         crossAxisSpacing: 2,
-//         mainAxisSpacing: 2,
-//       ),
-//       itemCount: count,
-//       itemBuilder: (context, index) {
-//         return Container(
-//           color: Colors.blue,
-//           child: Text('$value'),
-//         );
-//       },
-//     );
-//   }
-// }
-
-// class StaggeredTest extends StatelessWidget {
-//   StaggeredTest(this.count, this.value);
-//   final int count;
-//   final int value;
-
-//   @override
-//   Widget build(BuildContext context) {
-//     return StaggeredGridView.countBuilder(
-//       itemCount: count,
-//       crossAxisCount: 3,
-//       crossAxisSpacing: 2,
-//       mainAxisSpacing: 2,
-//       addAutomaticKeepAlives: false,
-//       staggeredTileBuilder: (index) => StaggeredTile.extent(1, 30),
-//       itemBuilder: (context, index) {
-//         return Container(
-//           color: Colors.green,
-//           child: Text('$value'),
-//         );
-//       },
-//     );
-//   }
-// }
+  @override
+  Widget build(BuildContext context) {
+    return StaggeredGridView.countBuilder(
+      itemCount: count,
+      crossAxisCount: 3,
+      crossAxisSpacing: 2,
+      mainAxisSpacing: 2,
+      addAutomaticKeepAlives: false,
+      staggeredTileBuilder: (index) => StaggeredTile.extent(1, 30),
+      itemBuilder: (context, index) {
+        return Container(
+          color: Colors.green,
+          child: Text('$value'),
+        );
+      },
+    );
+  }
+}
diff --git a/lib/src/widgets/sliver.dart b/lib/src/widgets/sliver.dart
@@ -88,6 +88,17 @@ class SliverVariableSizeBoxAdaptorElement extends RenderObjectElement
   @override
   RenderSliverVariableSizeBoxAdaptor get renderObject => super.renderObject;
 
+  @override
+  void update(covariant SliverVariableSizeBoxAdaptorWidget newWidget) {
+    final SliverVariableSizeBoxAdaptorWidget oldWidget = widget;
+    super.update(newWidget);
+    final SliverChildDelegate newDelegate = newWidget.delegate;
+    final SliverChildDelegate oldDelegate = oldWidget.delegate;
+    if (newDelegate != oldDelegate &&
+        (newDelegate.runtimeType != oldDelegate.runtimeType ||
+            newDelegate.shouldRebuild(oldDelegate))) performRebuild();
+  }
+
   // We inflate widgets at two different times:
   //  1. When we ourselves are told to rebuild (see performRebuild).
   //  2. When our render object needs a new child (see createChild).
@@ -129,7 +140,8 @@ class SliverVariableSizeBoxAdaptorElement extends RenderObjectElement
   }
 
   Widget _build(int index) {
-    return _childWidgets[index] = widget.delegate.build(this, index);
+    return _childWidgets.putIfAbsent(
+        index, () => widget.delegate.build(this, index));
   }
 
   @override

diff --git a/pubspec.yaml b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: flutter_staggered_grid_view
 description: A Flutter staggered grid view
-version: 0.2.6
+version: 0.2.7
 author: Romain Rastel <lets4r@gmail.com>
 homepage: https://github.com/letsar/flutter_staggered_grid_view
 dependencies: