feat: 實作登出

點擊登出按鈕後刪除share preference 資料及跳轉回登入畫面

lib/PersonalInfo.dart

@@ -1,5 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
+import 'package:persistent_bottom_nav_bar_v2/persistent_bottom_nav_bar_v2.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 import 'package:topic/BottomNavBar.dart';
 import 'package:topic/main.dart';
 import 'package:topic/HomePage.dart';
@@ -109,6 +111,19 @@ class _PersonalInfoState extends State<PersonalInfo> {
     }
   }
 
+  void _loginOut() async {
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    // remove all data in share preference(user data which save to identify user or others)
+    prefs.clear();
+    // navbar router setting
+    // replace screen with LoginPage and without navbar
+    pushReplacementWithoutNavBar(
+        context,
+        MaterialPageRoute(
+          builder: (context) => LoginPage(),
+        ));
+  }
+
   //頁面
   @override
   Widget build(BuildContext context) {
@@ -208,7 +223,9 @@ class _PersonalInfoState extends State<PersonalInfo> {
                   width: 60,
                 ),
                 ElevatedButton(
-                  onPressed: () {},
+                  onPressed: () {
+                    _loginOut();
+                  },
                   child: Text('登出'),
                   style: TextButton.styleFrom(
                     backgroundColor: Color(0xFFF5E3C3),

lib/main.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 import 'package:topic/HomePage.dart';
 import 'package:mysql_client/mysql_client.dart';
 import 'package:topic/RegisterPage.dart';
@@ -22,6 +23,7 @@ class _LoginPageState extends State<LoginPage> {
   void initState() {//初始化
     super.initState();
     _fetchData();//連資料庫
+    _CheckPreLoginInfo();//確定有先前有無登入
   }
 
   void _fetchData() async {
@@ -40,6 +42,29 @@ class _LoginPageState extends State<LoginPage> {
     await conn.connect();
   }
 
+  void _CheckPreLoginInfo() async{
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    //get user data from share preference else set empty to check not login before
+    String loginUserEmail = prefs.getString("email") ?? "";
+    //replace screen to HomePage if there are previous data in share preference
+    if(loginUserEmail != ""){
+      Navigator.pushReplacement(
+        context,
+        MaterialPageRoute(
+          builder: (context) => HomePage(
+            email: loginUserEmail,
+          ),
+        ),
+      );
+    }
+  }
+
+  void _setLoginInfo(String email) async{
+    //save user email into share preference to let app can auto login next open
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    prefs.setString("email", email);
+  }
+
   @override
   Widget build(BuildContext context) {
     debugPaintSizeEnabled=false;
@@ -180,6 +205,7 @@ class _LoginPageState extends State<LoginPage> {
         _emailController.clear();
         _ageController.clear();
         // 如果找到匹配的帳號，登入成功，跳轉到主頁
+        _setLoginInfo(email);
         Navigator.pushReplacement(
           context,
           MaterialPageRoute(

pubspec.yaml

@@ -41,6 +41,7 @@ dependencies:
   http: ^1.2.2
   webview_flutter: ^4.8.0
   persistent_bottom_nav_bar_v2: ^5.3.0
+  shared_preferences: ^2.2.3
 
 dev_dependencies:
   flutter_test: