From 64fa91647a779991c804f1a8738713e7b52ea8d7 Mon Sep 17 00:00:00 2001
From: AlexVincent525 <github@alexv525.com>
Date: Wed, 19 Feb 2020 17:58:18 +0800
Subject: [PATCH] :sparkles: Add none connectivity dialog.

---
 lib/constants/instances.dart |  2 +
 lib/main.dart                | 79 +++++++++++++++++++++++++++++++++---
 2 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/lib/constants/instances.dart b/lib/constants/instances.dart
index c8669040..4bf7fa66 100644
--- a/lib/constants/instances.dart
+++ b/lib/constants/instances.dart
@@ -1,6 +1,7 @@
 import 'dart:math' as math;
 
 import 'package:flutter/material.dart';
+import 'package:connectivity/connectivity.dart';
 import 'package:event_bus/event_bus.dart';
 import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 
@@ -22,6 +23,7 @@ class Instances {
   static final EventBus eventBus = EventBus();
   static final navigatorKey = GlobalKey<NavigatorState>();
   static AppLifecycleState appLifeCycleState = AppLifecycleState.resumed;
+  static ConnectivityResult connectivityResult;
 
   static final appsPageStateKey = GlobalKey<AppsPageState>();
   static final courseSchedulePageStateKey = GlobalKey<CourseSchedulePageState>();
diff --git a/lib/main.dart b/lib/main.dart
index 9733b02c..05736a8f 100755
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -1,8 +1,11 @@
+import 'dart:async';
 import 'dart:io';
+import 'dart:ui' as ui;
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/foundation.dart';
+import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import 'package:connectivity/connectivity.dart';
 import 'package:flutter_screenutil/flutter_screenutil.dart';
@@ -48,23 +51,30 @@ class OpenJMUApp extends StatefulWidget {
 }
 
 class OpenJMUAppState extends State<OpenJMUApp> with WidgetsBindingObserver {
-  final connectivitySubscription = Connectivity().onConnectivityChanged.listen(
-    (ConnectivityResult result) {
-      Instances.eventBus.fire(ConnectivityChangeEvent(result));
-      debugPrint('Current connectivity: $result');
-    },
-  );
+  StreamSubscription connectivitySubscription;
 
   int initAction;
 
   Brightness get _platformBrightness => Screens.mediaQuery.platformBrightness ?? Brightness.light;
 
+  ToastFuture connectivityToastFuture;
+
   @override
   void initState() {
     debugPrint('Current platform is: ${Platform.operatingSystem}');
     WidgetsBinding.instance.addObserver(this);
     tryRecoverLoginInfo();
 
+    Connectivity().checkConnectivity().then(checkIfNoConnectivity);
+    connectivitySubscription = Connectivity().onConnectivityChanged.listen(
+      (ConnectivityResult result) {
+        checkIfNoConnectivity(result);
+        Instances.eventBus.fire(ConnectivityChangeEvent(result));
+        Instances.connectivityResult = result;
+        debugPrint('Current connectivity: $result');
+      },
+    );
+
     Instances.eventBus
       ..on<TicketGotEvent>().listen((event) {
         if (!currentUser.isTeacher) {
@@ -159,6 +169,63 @@ class OpenJMUAppState extends State<OpenJMUApp> with WidgetsBindingObserver {
     ));
   }
 
+  void checkIfNoConnectivity(ConnectivityResult result) {
+    if (result == ConnectivityResult.none) {
+      if (mounted) {
+        connectivityToastFuture = showToastWidget(
+          noConnectivityWidget,
+          duration: 999.weeks,
+          handleTouch: true,
+        );
+      } else {
+        SchedulerBinding.instance.addPostFrameCallback((_) {
+          connectivityToastFuture = showToastWidget(
+            noConnectivityWidget,
+            duration: 999.weeks,
+            handleTouch: true,
+          );
+        });
+      }
+    } else {
+      if (Instances.connectivityResult == ConnectivityResult.none) {
+        connectivityToastFuture?.dismiss(showAnim: true);
+      }
+    }
+  }
+
+  Widget get noConnectivityWidget => Material(
+        color: Colors.black26,
+        child: BackdropFilter(
+          filter: ui.ImageFilter.blur(sigmaX: 2.0, sigmaY: 2.0),
+          child: Center(
+            child: Container(
+              width: Screens.width / 2,
+              height: Screens.width / 2,
+              padding: EdgeInsets.all(20.0),
+              decoration: BoxDecoration(
+                color: Theme.of(context).canvasColor,
+                shape: BoxShape.circle,
+              ),
+              child: Column(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: <Widget>[
+                  Icon(
+                    Icons.router,
+                    size: Screens.width / 6,
+                    color: Theme.of(context).iconTheme.color,
+                  ),
+                  SizedBox(height: Screens.width / 20),
+                  Text(
+                    '检查网络连接',
+                    style: Theme.of(context).textTheme.body1.copyWith(fontSize: 20.0),
+                  ),
+                ],
+              ),
+            ),
+          ),
+        ),
+      );
+
   @override
   Widget build(BuildContext context) {
     return MultiProvider(