Merge pull request #44 from FlutterOpen/dev

add the StreamBuilder widget to build a list.

Author: nb312

lib/const/page_item_const.dart

@@ -277,4 +277,9 @@ const PAGE_ITEMS = [
     "img": PageImage.FLUTTER_OPEN,
     "click": PageName.ASYNC_FUTURE,
   },
+  {
+    "title": PageName.ASYNC_STREAM_BUILDER,
+    "img": PageImage.FLUTTER_OPEN,
+    "click": PageName.ASYNC_STREAM_BUILDER,
+  },
 ];

lib/const/page_name_const.dart

@@ -61,4 +61,5 @@ class PageName {
   static const INTER_POINTER = "AbsorbPointer";
   static const INTER_SCROLLABLE = "Scrollable";
   static const ASYNC_FUTURE = "FutureBuilder";
+  static const ASYNC_STREAM_BUILDER = "StreamBuilder";
 }

lib/main.dart

@@ -74,6 +74,7 @@ class FlutterOpenApp extends StatelessWidget {
         PageName.INTER_DISMISSIBLE: (context) => DismissiblePage(),
         PageName.INTER_POINTER: (context) => PointerPage(),
         PageName.ASYNC_FUTURE: (context) => FuturePage(),
+        PageName.ASYNC_STREAM_BUILDER: (context) => StreamBuilderPage(),
       },
     );
   }

lib/page/async/FuturePage.dart

@@ -20,7 +20,7 @@ class _FutureState extends State<FuturePage> {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: Text("Hello world"),
+        title: Text(PageName.ASYNC_FUTURE),
       ),
       body: Container(
         child: FutureBuilder<String>(
@@ -36,8 +36,7 @@ class _FutureState extends State<FuturePage> {
                 if (snapshot.hasError) return Text('Error: ${snapshot.error}');
                 return Text('Result: ${snapshot.data}');
             }
-            return RefreshIndicator(
-                child: null, onRefresh: null); // unreachable
+            return null; // unreachable
           },
         ),
       ),

lib/page/async/StreamBuilderPage.dart

@@ -0,0 +1,81 @@
+///
+/// Created by NieBin on 2019/6/13
+/// Github: https://github.com/nb312
+/// Email: niebin312@gmail.com
+import "package:flutter/material.dart";
+import 'package:flutter_widgets/const/_const.dart';
+
+class StreamBuilderPage extends StatefulWidget {
+  @override
+  _StreamBuilderState createState() => _StreamBuilderState();
+}
+
+class _StreamBuilderState extends State<StreamBuilderPage> {
+  Stream<List<String>> _stream() =>
+      Stream<List<String>>.fromFuture(_futureList());
+
+  Future<List<String>> _futureList() async {
+    return _listData;
+  }
+
+  List<String> _listData = [
+    "Hello",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+    "World",
+  ];
+
+  Widget _streamBuildList() => StreamBuilder(
+        builder: (BuildContext context, AsyncSnapshot<List<String>> snapshot) {
+          switch (snapshot.connectionState) {
+            case ConnectionState.none:
+              return Text('Press button to start.');
+            case ConnectionState.active:
+            case ConnectionState.waiting:
+              return Text('Awaiting result...');
+            case ConnectionState.done:
+              if (snapshot.hasError) return Text('Error: ${snapshot.error}');
+              return ListView.builder(
+                  itemCount: snapshot.data.length,
+                  itemBuilder: (context, index) => Container(
+                        constraints: BoxConstraints.expand(height: 100),
+                        color: index % 2 == 0 ? RED_LIGHT : PURPLE,
+                        child: Text(
+                          snapshot.data[index],
+                          style: TextStyle(color: TEXT_BLACK, fontSize: 20),
+                        ),
+                      ));
+          }
+          return null; // unreachable
+        },
+        stream: _stream(),
+      );
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(PageName.ASYNC_STREAM_BUILDER),
+      ),
+      body: _streamBuildList(),
+    );
+  }
+}

lib/page/async/_async.dart

@@ -4,3 +4,4 @@
 /// Email: niebin312@gmail.com
 ///
 export "FuturePage.dart";
+export 'StreamBuilderPage.dart';