fix: 两次返回退出应用 issues #303

lib/pages/main/controller.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 
+import 'package:flutter/services.dart';
 import 'package:flutter_smart_dialog/flutter_smart_dialog.dart';
 import 'package:get/get.dart';
 import 'package:flutter/material.dart';
@@ -66,15 +67,15 @@ class MainController extends GetxController {
     hideTabBar = setting.get(SettingBoxKey.hideTabBar, defaultValue: true);
   }
 
-  Future<bool> onBackPressed(BuildContext context) {
+  void onBackPressed(BuildContext context) {
     if (_lastPressedAt == null ||
         DateTime.now().difference(_lastPressedAt!) >
             const Duration(seconds: 2)) {
       // 两次点击时间间隔超过2秒，重新记录时间戳
       _lastPressedAt = DateTime.now();
       SmartDialog.showToast("再按一次退出Pili");
-      return Future.value(false); // 不退出应用
+      return; // 不退出应用
     }
-    return Future.value(true); // 退出应用
+    SystemNavigator.pop(); // 退出应用
   }
 }

lib/pages/main/view.dart

@@ -94,7 +94,10 @@ class _MainAppState extends State<MainApp> with SingleTickerProviderStateMixin {
     localCache.put('sheetHeight', sheetHeight);
     localCache.put('statusBarHeight', statusBarHeight);
     return PopScope(
-      onPopInvoked: (bool status) => _mainController.onBackPressed(context),
+      canPop: false,
+      onPopInvoked: (bool didPop) async {
+        _mainController.onBackPressed(context);
+      },
       child: Scaffold(
         extendBody: true,
         body: PageView(