feat(): 观察者模式完成

聂彬 · 聂彬 · commit 50cb34c30b9c · 2020-04-13T11:43:27.000+08:00
diff --git a/README.md b/README.md
@@ -24,4 +24,5 @@
 15. 解释器模式
 16. 迭代器模式
 17. 中介者模式
-18. 备忘录模式
+18. 备忘录模式
+19. 观察者模式
diff --git a/lib/constant/string_const.dart b/lib/constant/string_const.dart
@@ -58,4 +58,6 @@ class StringConst {
 
   //备忘录模式
   static const String MEMORY_ = "备忘录模式";
+  //备忘录模式
+  static const String OBSERVER_ = "观察者模式";
 }
diff --git a/lib/main.dart b/lib/main.dart
@@ -13,6 +13,7 @@ import 'package:flutter_design/page/interpreter/intepreter_page.dart';
 import 'package:flutter_design/page/iterator/Iterator_page.dart';
 import 'package:flutter_design/page/memory/memory_page.dart';
 import 'package:flutter_design/page/midd/mid_page.dart';
+import 'package:flutter_design/page/observer/observer_page.dart';
 import 'package:flutter_design/page/proxy/proxy_page.dart';
 
 import 'constant/page_const.dart';
@@ -51,6 +52,7 @@ class MyApp extends StatelessWidget {
         PageConst.ITERATOR_PAGE: (context) => IteratorPage(),
         PageConst.MEDIATOR_PAGE: (context) => MidPage(),
         PageConst.MEMENTO_PAGE: (context) => MemoryPage(),
+        PageConst.OBSERVER_PAGE: (context) => ObserverPage(),
       },
     );
   }
diff --git a/lib/page/home_page.dart b/lib/page/home_page.dart
@@ -33,6 +33,7 @@ Map<String, String> map = {
   PageConst.ITERATOR_PAGE: StringConst.ITERATOR_,
   PageConst.MEDIATOR_PAGE: StringConst.MID_,
   PageConst.MEMENTO_PAGE: StringConst.MEMORY_,
+  PageConst.OBSERVER_PAGE: StringConst.OBSERVER_,
 };
 
 class _HomePageState extends State<HomePage> {
diff --git a/lib/page/observer/observer_mode.dart b/lib/page/observer/observer_mode.dart
@@ -0,0 +1,75 @@
+/// Created by NieBin on 2020-04-13
+/// Github: https://github.com/nb312
+/// Email: niebin312@gmail.com
+abstract class ISubject {
+  void attach(IObserver observer);
+
+  void detach(IObserver observer);
+
+  void detachAll();
+
+  void notify();
+}
+
+class RealSubject extends ISubject {
+  List<IObserver> _list;
+  String _name;
+
+  String get name => _name;
+
+  set name(String n) {
+    _name = n;
+    notify();
+  }
+
+  RealSubject() {
+    _list = List();
+  }
+
+  @override
+  void attach(IObserver observer) {
+    if (observer == null) return;
+    if (!_list.contains(observer)) {
+      _list.add(observer);
+    }
+  }
+
+  @override
+  void detach(IObserver observer) {
+    if (_list.contains(observer)) {
+      _list.remove(observer);
+    }
+  }
+
+  @override
+  void detachAll() {
+    _list.clear();
+  }
+
+  @override
+  void notify() {
+    for (IObserver observer in _list) {
+      observer.update(name);
+    }
+  }
+}
+
+abstract class IObserver {
+  void update(String name);
+}
+
+class AObserver extends IObserver {
+  String content;
+
+  @override
+  void update(String name) {
+    print("我是A,收到外星人： $name");
+  }
+}
+
+class BObserver extends IObserver {
+  @override
+  void update(String name) {
+    print("我是B,收到一个东西: $name");
+  }
+}
diff --git a/lib/page/observer/observer_page.dart b/lib/page/observer/observer_page.dart
@@ -0,0 +1,71 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_design/page/observer/observer_mode.dart';
+
+/// Created by NieBin on 2020-04-13
+/// Github: https://github.com/nb312
+/// Email: niebin312@gmail.com
+
+class ObserverPage extends StatefulWidget {
+  @override
+  _ObserverPageState createState() => _ObserverPageState();
+}
+
+class _ObserverPageState extends State<ObserverPage> {
+  List<IObserver> _observers;
+  RealSubject _subject;
+
+  @override
+  void initState() {
+    _observers = List();
+    _subject = RealSubject();
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text("观察者模式"),
+      ),
+      body: Container(
+        child: Column(
+          children: <Widget>[
+            FlatButton(
+              color: Colors.orange,
+              child: Padding(
+                padding: const EdgeInsets.all(8.0),
+                child: Text("添加A型观察者"),
+              ),
+              onPressed: () {
+                _subject.attach(AObserver());
+              },
+            ),
+            SizedBox(height: 10),
+            FlatButton(
+              color: Colors.orange,
+              child: Padding(
+                padding: const EdgeInsets.all(8.0),
+                child: Text("添加B型观察者"),
+              ),
+              onPressed: () {
+                _subject.attach(BObserver());
+              },
+            ),
+            SizedBox(height: 10),
+            FlatButton(
+              color: Colors.orange,
+              child: Padding(
+                padding: const EdgeInsets.all(8.0),
+                child: Text("发个消息通知大家"),
+              ),
+              onPressed: () {
+                _subject.name = "诸国缸体";
+                _subject.notify();
+              },
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}

Original file line number	Diff line number	Diff line change
`@@ -58,4 +58,6 @@ class StringConst {`
`58`	`58`
`59`	`59`	`//备忘录模式`
`60`	`60`	`static const String MEMORY_ = "备忘录模式";`
	`61`	`+ //备忘录模式`
	`62`	`+ static const String OBSERVER_ = "观察者模式";`
`61`	`63`	`}`