From ff322cd2dd5f1e89683f34ee8b2832eaae03e58a Mon Sep 17 00:00:00 2001
From: Matt Smith <me@mattthedev.codes>
Date: Wed, 8 Jul 2020 14:09:08 -0500
Subject: [PATCH] Modified Permissions Flow (#1005)

Permissions flow for Android was causing the white screen on initial permission grant on occasion. Moved permission grant to pre-TOTP page load.
---
 src/Android/MainActivity.cs             |  4 ++--
 src/App/Pages/Vault/AddEditPage.xaml.cs |  8 ++++++++
 src/App/Utilities/PermissionManager.cs  | 21 +++++++++++++++++++++
 3 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 src/App/Utilities/PermissionManager.cs

diff --git a/src/Android/MainActivity.cs b/src/Android/MainActivity.cs
index d36a6df89..1cf8ba7fb 100644
--- a/src/Android/MainActivity.cs
+++ b/src/Android/MainActivity.cs
@@ -18,6 +18,7 @@ using Android.Nfc;
 using Bit.App.Utilities;
 using System.Threading.Tasks;
 using AndroidX.Core.Content;
+using ZXing.Net.Mobile.Android;
 
 namespace Bit.Droid
 {
@@ -193,8 +194,7 @@ namespace Bit.Droid
             else
             {
                 Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);
-                ZXing.Net.Mobile.Forms.Android.PermissionsHandler.OnRequestPermissionsResult(
-                    requestCode, permissions, grantResults);
+                PermissionsHandler.OnRequestPermissionsResult(requestCode, permissions, grantResults);
             }
             base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
         }
diff --git a/src/App/Pages/Vault/AddEditPage.xaml.cs b/src/App/Pages/Vault/AddEditPage.xaml.cs
index 654159c40..3a8d9cc06 100644
--- a/src/App/Pages/Vault/AddEditPage.xaml.cs
+++ b/src/App/Pages/Vault/AddEditPage.xaml.cs
@@ -1,12 +1,14 @@
 using Bit.App.Abstractions;
 using Bit.App.Models;
 using Bit.App.Resources;
+using Bit.App.Utilities;
 using Bit.Core;
 using Bit.Core.Abstractions;
 using Bit.Core.Enums;
 using Bit.Core.Utilities;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using Xamarin.Essentials;
 using Xamarin.Forms;
 using Xamarin.Forms.PlatformConfiguration;
 using Xamarin.Forms.PlatformConfiguration.iOSSpecific;
@@ -243,6 +245,12 @@ namespace Bit.App.Pages
         {
             if (DoOnce())
             {
+                var cameraPermission = await PermissionManager.CheckAndRequestPermissionAsync(new Permissions.Camera());
+                if (cameraPermission != PermissionStatus.Granted)
+                {
+                    return;
+                }
+
                 var page = new ScanPage(key =>
                 {
                     Device.BeginInvokeOnMainThread(async () =>
diff --git a/src/App/Utilities/PermissionManager.cs b/src/App/Utilities/PermissionManager.cs
new file mode 100644
index 000000000..8af2ecff2
--- /dev/null
+++ b/src/App/Utilities/PermissionManager.cs
@@ -0,0 +1,21 @@
+using System.Threading.Tasks;
+using Xamarin.Essentials;
+using static Xamarin.Essentials.Permissions;
+
+namespace Bit.App.Utilities
+{
+    public static class PermissionManager
+    {
+        public static async Task<PermissionStatus> CheckAndRequestPermissionAsync<T>(T permission)
+            where T : BasePermission
+        {
+            var status = await permission.CheckStatusAsync();
+            if (status != PermissionStatus.Granted)
+            {
+                status = await permission.RequestAsync();
+            }
+
+            return status;
+        }
+    }
+}