added shared preferences

lib/bottom_navigation_bar_buttons/settings/settings.dart

 import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
-
-import 'package:deggendorf_app/bottom_navigation_bar_buttons/settings/dropdownbutton.dart';
-import 'package:deggendorf_app/bottom_navigation_bar_buttons/settings/standardsettingbutton.dart';
-
+import 'package:shared_preferences/shared_preferences.dart';
 
 class SettingScreen extends StatelessWidget {
   const SettingScreen({Key? key}) : super(key: key);
@@ -33,3 +30,174 @@ class SettingScreen extends StatelessWidget {
     );
   }
 }
+
+class DropdownSettingButton extends StatefulWidget {
+  const DropdownSettingButton({Key? key}) : super(key: key);
+
+  @override
+  State<DropdownSettingButton> createState() => _DropdownSettingButtonState();
+}
+
+class _DropdownSettingButtonState extends State<DropdownSettingButton> {
+  bool _expanded = false;
+  String currentCity = "Deggendorf";
+
+  getCurrentCityFromSharedPreferences() async {
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    String val = prefs.getString('currentCity') ?? "Not Selected";
+    currentCity = val;
+  }
+
+  setCurrentCityInSharedPreferences(String newCity) async{
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    prefs.setString('currentCity', newCity);
+  }
+
+
+  @override
+  Widget build(BuildContext context) {
+    return ExpansionPanelList(
+      animationDuration: Duration(microseconds: 2000),
+      children:[
+        ExpansionPanel(
+            canTapOnHeader: true,
+            isExpanded: _expanded,
+            headerBuilder: (context, isExpanded){
+              return ListTile(
+                title: Text(currentCity,
+                    style: TextStyle(fontSize: 22, color: Color.fromRGBO(
+                        1, 1, 1, 0.49411764705882355))
+                ),
+              );
+            },
+            body: Column(
+              children: <Widget> [
+                TextButton(
+                    onPressed: (){
+                      setCurrentCityInSharedPreferences("Deggendorf");
+                      _expanded = false;
+                      getCurrentCityFromSharedPreferences();
+                      setState(() {
+                      });
+                    },
+                    child: Text(
+                      "Deggendorf", style: TextStyle(fontSize: 20, color: Color.fromRGBO(
+                        1, 1, 1, 0.49411764705882355)),
+                    )
+                ),
+                TextButton(
+                    onPressed: (){
+                      setCurrentCityInSharedPreferences("Plattling");
+                      _expanded = false;
+                      getCurrentCityFromSharedPreferences();
+                      setState(() {
+                      });
+                    },
+                    child: Text(
+                      "Plattling", style: TextStyle(fontSize: 20, color: Color.fromRGBO(
+                        1, 1, 1, 0.49411764705882355)),
+                    )
+                ),
+              ],
+            )
+        )
+      ],
+      expansionCallback: (panelIndex, isExpanded){
+        _expanded = !_expanded;
+        setState(() {
+
+        });
+      },
+    );
+  }
+}
+
+
+class StandardSettingButton extends StatefulWidget {
+  const StandardSettingButton({Key? key,
+    required this.xOffset,
+    required this.title,
+    required this.label
+  }) : super(key: key);
+
+  final double xOffset;
+  final String title;
+  final String label;
+
+  @override
+  State<StandardSettingButton> createState() => _StandardSettingButtonState();
+}
+
+class _StandardSettingButtonState extends State<StandardSettingButton> {
+
+  bool isPassword(){
+    if (widget.title == "Kennwort"){
+      return true;
+    }
+    return false;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return TextButton(
+        onPressed: (){
+          showDialog(
+            context: context,
+            builder: (context) => AlertDialog(
+              title: Text(
+                "Wollen Sie ${widget.title} ändern?",
+                style: TextStyle(
+                    fontSize: 16
+                ),
+              ),
+              content: TextField(
+                obscureText: isPassword() ,
+                decoration: InputDecoration(
+                    hintText: "geben Sie ${widget.title} ein"
+                ),
+              ),
+              actions: [
+                TextButton(
+                    onPressed: (){Navigator.pop(context);},
+                    child: Text("ändern")
+                ),
+                TextButton(
+                    onPressed: (){
+                      Navigator.pop(context);
+                    },
+                    child: Text("abbrechen")
+                )
+              ],
+            ),
+          );
+        },
+        child: Row(
+          children: <Widget>[
+            Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                Text(
+                  widget.title,
+                  style: TextStyle(fontSize: 25, color: Color.fromRGBO(
+                      1, 1, 1, 0.49411764705882355)),
+                ),
+                Text(
+                  "drücken um das ${widget.title} zu ändern",
+                  style: TextStyle(fontSize: 10, color: Color.fromRGBO(
+                      1, 1, 1, 0.3764705882352941)),
+                )
+              ],
+            ),
+            SizedBox(
+              width: widget.xOffset,
+            ),
+            Icon(
+              Icons.keyboard_arrow_right_rounded,
+              color: Color.fromRGBO(1, 1, 1, 0.49411764705882355),
+              size: 40,
+            )
+          ],
+        )
+    );
+  }
+}