fix: Persistent settings

lib/components/settings_switch_list_tile.dart

@@ -0,0 +1,41 @@
+import 'package:flutter/material.dart';
+
+import 'matrix.dart';
+
+class SettingsSwitchListTile extends StatefulWidget {
+  final bool defaultValue;
+  final String storeKey;
+  final String title;
+  final Function(bool) onChanged;
+
+  const SettingsSwitchListTile({
+    Key key,
+    this.defaultValue = false,
+    @required this.storeKey,
+    @required this.title,
+    this.onChanged,
+  }) : super(key: key);
+
+  @override
+  _SettingsSwitchListTileState createState() => _SettingsSwitchListTileState();
+}
+
+class _SettingsSwitchListTileState extends State<SettingsSwitchListTile> {
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder<bool>(
+      future: Matrix.of(context).store.getItemBool(widget.storeKey),
+      builder: (context, snapshot) => SwitchListTile(
+        value: snapshot.data ?? widget.defaultValue,
+        title: Text(widget.title),
+        onChanged: (bool newValue) async {
+          widget.onChanged?.call(newValue);
+          await Matrix.of(context)
+              .store
+              .setItem(widget.storeKey, newValue.toString());
+          setState(() => null);
+        },
+      ),
+    );
+  }
+}