添加设置语言demo

app/src/main/ets/pages/Index.ets

@@ -61,7 +61,8 @@ struct Index {
       name: 'System',
       items: [
         {name: "Scheme", page: 'pages/system/SchemePage'},
-        {name: "MVVM", page: 'pages/mvvm/HomePage'}
+        {name: "MVVM", page: 'pages/mvvm/HomePage'},
+        {name: "SetLanguage", page: 'pages/system/SetLanguagePage'}
       ]
     }
   ];

app/src/main/ets/pages/system/SetLanguagePage.ets

@@ -0,0 +1,38 @@
+import { TitleBar } from '@devwiki/common_ui';
+import { i18n } from '@kit.LocalizationKit';
+
+@Entry
+@Component
+struct SetLanguagePage {
+
+  private readonly languageGroup = "languageGroup"
+  @State selectedIndex: number = 0;
+
+  build() {
+    Column() {
+      TitleBar({
+        title: $r('app.string.set_language_title')
+      });
+      Row() {
+        Text('简体中文');
+        Radio({group: this.languageGroup, value: '简体中文'}).checked(true).onChange(isChecked => {
+          if (isChecked) {
+            this.selectedIndex = 0;
+          }
+        });
+      }
+      Row() {
+        Text('英文');
+        Radio({group: this.languageGroup, value: '英文'}).checked(false).onChange(isChecked => {
+          if (isChecked) {
+            this.selectedIndex = 1;
+          }
+        });
+      }
+
+      Button('修改语言').onClick(() => {
+        i18n.System.setAppPreferredLanguage(this.selectedIndex == 0 ? 'zh-Hans' : 'en-US')
+      })
+    }.width('100%').height('100%')
+  }
+}