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lib/widgets/components/Scaffold/ScaffoldState/demo.dart

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+/**
+ * Created with Android Studio.
+ * User: ryan
+ * Date: 2019/1/6
+ * Time: 下午7:33
+ * email: sanfann@alibaba-inc.com
+ * tartget: TabBar 的示例
+ */
+
+import 'package:flutter/material.dart';
+
+class ScaffoldStateDemo extends StatefulWidget {
+  const ScaffoldStateDemo() : super();
+
+  @override
+  State<StatefulWidget> createState() => _ScaffoldStateDemo();
+}
+
+/*
+* AppBar 默认的实例,有状态
+* */
+class _ScaffoldStateDemo extends State with SingleTickerProviderStateMixin {
+
+  int count = 0;
+  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
+  @override
+  Widget build(BuildContext context) {
+    // 如果省略了 leading ，但 AppBar 在带有 Drawer 的 Scaffold 中，则会插入一个 button 以打开 Drawer。
+    // 否则，如果最近的 Navigator 具有任何先前的 router ，则会插入BackButton。
+    // 这种行为可以通过设置来关闭automaticallyImplyLeading 为false。在这种情况下，空的 leading widget 将导致 middle/title widget 拉伸开始。
+    return new SizedBox(
+        height: 500,
+        child:new Scaffold(
+          key:_scaffoldKey,
+          appBar: AppBar(
+            title: Text('ScaffoldState Demo'),
+          ),
+          body:  Center(
+            child: Column(
+              children: <Widget>[
+                RaisedButton(
+                  child: Text('点我试试呼出SnackBar&Drawer'),
+                  onPressed: () {
+                    _scaffoldKey.currentState.openDrawer();
+                    _scaffoldKey.currentState.showSnackBar(const SnackBar(
+                        content: Text("我是通过ScaffoldState的方式呼出的SnackBar.")
+                    ));
+                  },
+                )
+              ],
+            ),
+          ),
+          drawer: Drawer(
+            child: Column(
+              children: <Widget>[
+                const UserAccountsDrawerHeader(
+                  accountName: Text('Peter Widget'),
+                  accountEmail: Text('peter.widget@example.com'),
+                  currentAccountPicture: CircleAvatar(
+                    backgroundImage: AssetImage(
+                      'people/square/peter.png',
+                      package: 'flutter_gallery_assets',
+                    ),
+                  ),
+                  margin: EdgeInsets.zero,
+                ),
+//                MediaQuery.removePadding(
+//                  context: context,
+//                  // DrawerHeader consumes top MediaQuery padding.
+//                  removeTop: true,
+//                  child: const ListTile(
+//                    leading: Icon(Icons.payment),
+//                    title: Text('Placeholder'),
+//                  ),
+//                ),
+              ],
+            ),
+          ),
+
+        )
+
+    );
+  }
+}

lib/widgets/components/Scaffold/ScaffoldState/index.dart

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+/**
+ * Created with Android Studio.
+ * User: 三帆
+ * Date: 07/01/2019
+ * Time: 10:26
+ * email: sanfan.hx@alibaba-inc.com
+ * tartget:  xxx
+ */
+import '../../../../common/widget_demo.dart';
+import 'package:flutter/material.dart';
+import 'demo.dart';
+
+const String _Text0 = """
+### **简介**
+> Scaffold的State对象
+
+通常用来控制**SnackBars**和**BottomSheets**和**Drawer**的显示与隐藏. 
+
+
+
+### **基本用法**
+- 通过为Scaffold定义key属性, 声明_scaffoldState, 通过_scaffoldState直接调用scaffoldState方法
+- 当组件无法直接为Scaffold定义key属性时, 可以通过 **Context**与**Scaffold.of**获取父级scaffoldState
+
+""";
+
+
+class Demo extends StatefulWidget {
+  static const String routeName = '/components/Scaffold/ScaffoldState';
+
+  @override
+  _DemoState createState() => _DemoState();
+}
+
+class _DemoState extends State<Demo> {
+  @override
+  Widget build(BuildContext context) {
+    return WidgetDemo(
+      title: 'ScaffoldState',
+      codeUrl: 'components/Scaffold/ScaffoldState/demo.dart',
+      contentList: [
+        _Text0,
+        ScaffoldStateDemo()
+      ],
+      docUrl: 'https://docs.flutter.io/flutter/material/ScaffoldState-class.html',
+    );
+  }
+}