From c9669dba15af635f2389816effc4f4572bedfd1d Mon Sep 17 00:00:00 2001
From: Tristan Roux <tr.tristan-roux@outlook.fr>
Date: Tue, 16 Apr 2019 21:48:46 +0200
Subject: [PATCH] Adding permission request support in the preference screen.

---
 Opus/MainActivity.cs                         |  4 +-
 Opus/Resources/Portable Class/Preferences.cs | 53 ++++++++++++++++++--
 2 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/Opus/MainActivity.cs b/Opus/MainActivity.cs
index 38261bd..a8b36bf 100644
--- a/Opus/MainActivity.cs
+++ b/Opus/MainActivity.cs
@@ -67,7 +67,7 @@ namespace Opus
         public bool SkipStop = false;
         public PlayerBehavior SheetBehavior;
 
-        private const int RequestCode = 8539;
+        public const int RequestCode = 8539;
         private const int WriteRequestCode = 2659;
         public const int NotifUpdateID = 4626;
         private const string versionURI = "https://raw.githubusercontent.com/AnonymusRaccoon/Opus/master/Opus/Assets/Version.txt";
@@ -794,7 +794,7 @@ namespace Opus
         public async Task<bool> GetWritePermission()
         {
             const string permission = Manifest.Permission.WriteExternalStorage;
-            if (Android.Support.V4.Content.ContextCompat.CheckSelfPermission(this, permission) == (int)Permission.Granted)
+            if (ContextCompat.CheckSelfPermission(this, permission) == (int)Permission.Granted)
             {
                 return true;
             }
diff --git a/Opus/Resources/Portable Class/Preferences.cs b/Opus/Resources/Portable Class/Preferences.cs
index f6bc044..53e6859 100644
--- a/Opus/Resources/Portable Class/Preferences.cs	
+++ b/Opus/Resources/Portable Class/Preferences.cs	
@@ -1,11 +1,15 @@
-using Android.App;
+using Android;
+using Android.App;
 using Android.Content;
+using Android.Content.PM;
 using Android.Content.Res;
 using Android.Gms.Auth.Api;
 using Android.Gms.Auth.Api.SignIn;
+using Android.Graphics;
 using Android.OS;
 using Android.Preferences;
 using Android.Runtime;
+using Android.Support.Design.Widget;
 using Android.Support.V7.App;
 using Android.Support.V7.Preferences;
 using Android.Views;
@@ -13,6 +17,7 @@ using Android.Widget;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Threading.Tasks;
 using AlertDialog = Android.Support.V7.App.AlertDialog;
 using Preference = Android.Support.V7.Preferences.Preference;
 using PreferenceManager = Android.Support.V7.Preferences.PreferenceManager;
@@ -25,6 +30,7 @@ namespace Opus.Resources.Portable_Class
     {
         public static Preferences instance;
         public Toolbar toolbar;
+        private bool? PermissionGot;
 
         protected override void OnCreate(Bundle savedInstanceState)
         {
@@ -78,9 +84,42 @@ namespace Opus.Resources.Portable_Class
             instance = null;
         }
 
+        public async Task<bool> GetReadPermission()
+        {
+            if (MainActivity.instance.HasReadPermission())
+                return true;
+
+            PermissionGot = null;
+            string[] permissions = new string[] { Manifest.Permission.ReadExternalStorage };
+            RequestPermissions(permissions, MainActivity.RequestCode);
+
+            while (PermissionGot == null)
+                await Task.Delay(10);
+
+            return (bool)PermissionGot;
+        }
+
+        public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Permission[] grantResults)
+        {
+            if (requestCode == MainActivity.RequestCode)
+            {
+                if (grantResults.Length > 0)
+                {
+                    if (grantResults[0] == Permission.Granted)
+                        PermissionGot = true;
+                    else
+                    {
+                        PermissionGot = false;
+                        Snackbar snackBar = Snackbar.Make(FindViewById(Resource.Id.PreferenceFragment), Resource.String.no_permission, Snackbar.LengthLong);
+                        snackBar.View.FindViewById<TextView>(Resource.Id.snackbar_text).SetTextColor(Color.White);
+                        snackBar.Show();
+                    }
+                }
+            }
+        }
+
         protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)
         {
-            base.OnActivityResult(requestCode, resultCode, data);
             if (requestCode == 5981)
             {
                 GoogleSignInResult result = Auth.GoogleSignInApi.GetSignInResultFromIntent(data);
@@ -95,6 +134,7 @@ namespace Opus.Resources.Portable_Class
                     MainActivity.instance.waitingForYoutube = false;
                 }
             }
+            base.OnActivityResult(requestCode, resultCode, data);
         }
 
         protected override void OnResume()
@@ -202,10 +242,13 @@ namespace Opus.Resources.Portable_Class
         }
 
         #region Download location
-        private void DownloadClick(object sender, Preference.PreferenceClickEventArgs e)
+        private async void DownloadClick(object sender, Preference.PreferenceClickEventArgs e)
         {
-            Preferences.instance.SupportFragmentManager.BeginTransaction().Replace(Resource.Id.PreferenceFragment, DownloadFragment.NewInstance(path)).AddToBackStack(null).Commit();
-            Preferences.instance.toolbar.Title = "Download Location";
+            if(await Preferences.instance.GetReadPermission())
+            {
+                Preferences.instance.SupportFragmentManager.BeginTransaction().Replace(Resource.Id.PreferenceFragment, DownloadFragment.NewInstance(path)).AddToBackStack(null).Commit();
+                Preferences.instance.toolbar.Title = "Download Location";
+            }
         }
         #endregion