network issues

Pixiview/MainPage.xaml.cs

@@ -6,6 +6,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using Pixiview.UI;
 using Pixiview.Utils;
+using Xamarin.Essentials;
 using Xamarin.Forms;
 
 namespace Pixiview
@@ -34,6 +35,7 @@ namespace Pixiview
         private readonly ParallelOptions parallelOptions = new ParallelOptions { MaxDegreeOfParallelism = Configs.MaxThreads };
 
         private IllustData illustData;
+        private bool loaded;
 
         public MainPage()
         {
@@ -45,12 +47,44 @@ namespace Pixiview
         public override void OnLoad()
         {
             App.DebugPrint($"folder: {Stores.PersonalFolder}");
-            Task.Run(DoLoadIllusts);
+        }
+
+        protected override void OnAppearing()
+        {
+            base.OnAppearing();
+
+            Connectivity.ConnectivityChanged += Connectivity_ConnectivityChanged;
+            if (!loaded && Stores.NetworkAvailable)
+            {
+                loaded = true;
+                Task.Run(DoLoadIllusts);
+            }
+        }
+
+        protected override void OnDisappearing()
+        {
+            base.OnDisappearing();
+
+            Connectivity.ConnectivityChanged -= Connectivity_ConnectivityChanged;
+        }
+
+        private void Connectivity_ConnectivityChanged(object sender, ConnectivityChangedEventArgs e)
+        {
+            if (!loaded && (e.NetworkAccess == NetworkAccess.Internet || e.NetworkAccess == NetworkAccess.ConstrainedInternet))
+            {
+                loaded = true;
+                Task.Run(DoLoadIllusts);
+            }
         }
 
         async void DoLoadIllusts()
         {
             illustData = await Stores.LoadIllustData();
+            if (illustData == null)
+            {
+                App.DebugError("illusts.load", "failed to load illusts data.");
+                return;
+            }
 
             var data = illustData.body.page.follow.Select(i =>
             {

Pixiview/Utils/Stores.cs

@@ -6,6 +6,7 @@ using System.Net.Http;
 using System.Text;
 using System.Threading.Tasks;
 using Newtonsoft.Json;
+using Xamarin.Essentials;
 using Xamarin.Forms;
 
 namespace Pixiview.Utils
@@ -19,6 +20,22 @@ namespace Pixiview.Utils
         private const string userFolder = "user-profile";
         private const string illustFile = "illust.json";
 
+        public static bool NetworkAvailable
+        {
+            get
+            {
+                try
+                {
+                    return Connectivity.NetworkAccess == NetworkAccess.Internet
+                        || Connectivity.NetworkAccess == NetworkAccess.ConstrainedInternet;
+                }
+                catch
+                {
+                    return false;
+                }
+            }
+        }
+
         public static async Task<IllustData> LoadIllustData()
         {
             var file = Path.Combine(PersonalFolder, illustFile);
@@ -144,6 +161,7 @@ namespace Pixiview.Utils
                 catch (Exception ex)
                 {
                     tries++;
+                    System.Threading.Thread.Sleep(400);
                     App.DebugError("try.do", $"tries: {tries}, error: {ex.Message}");
                 }
             }
@@ -163,28 +181,31 @@ namespace Pixiview.Utils
             {
                 BaseAddress = new Uri($"{uri.Scheme}://{uri.Host}")
             };
-            using (var request = new HttpRequestMessage(HttpMethod.Get, uri.PathAndQuery)
+            return TryCount(() =>
             {
-                Version = new Version(2, 0)
+                using (var request = new HttpRequestMessage(HttpMethod.Get, uri.PathAndQuery)
-            })
-            {
-                request.Headers.Referrer = referer == null ? Configs.Referer : new Uri(referer);
-                request.Headers.Add("user-agent", Configs.UserAgent);
-                if (headers != null)
                 {
-                    foreach (var (header, value) in headers)
+                    Version = new Version(2, 0)
+                })
+                {
+                    request.Headers.Referrer = referer == null ? Configs.Referer : new Uri(referer);
+                    request.Headers.Add("user-agent", Configs.UserAgent);
+                    if (headers != null)
                     {
-                        request.Headers.Add(header, value);
+                        foreach (var (header, value) in headers)
+                        {
+                            request.Headers.Add(header, value);
+                        }
                     }
+                    return client.SendAsync(request).Result;
                 }
-                return TryCount(() => client.SendAsync(request).Result);
+            });
-            }
         }
     }
 
     public static class Configs
     {
-        public static readonly WebProxy Proxy = new WebProxy("10.0.10.100", 8088);
+        public static readonly WebProxy Proxy = new WebProxy("router.tsanie.us", 8088);
         public static readonly Uri Referer = new Uri("https://www.pixiv.net/");
 
         public const int MaxThreads = 3;