improve message when storage access framework access permission is revoked

src/Kp2aBusinessLogic/Io/AndroidContentStorage.cs

@@ -2,12 +2,15 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Runtime.Serialization;
+using Android;
 using Android.Content;
 using Android.Database;
 using Android.OS;
 using Android.Provider;
 using Java.IO;
 using KeePassLib.Serialization;
+using Console = System.Console;
 
 namespace keepass2android.Io
 {
@@ -51,7 +54,20 @@ namespace keepass2android.Io
 
 		public Stream OpenFileForRead(IOConnectionInfo ioc)
 		{
-			return _ctx.ContentResolver.OpenInputStream(Android.Net.Uri.Parse(ioc.Path));
+		    try
+            { 
+		        return _ctx.ContentResolver.OpenInputStream(Android.Net.Uri.Parse(ioc.Path));
+		    }
+		    catch (Exception e)
+		    {
+		        if (e.Message.Contains("requires that you obtain access using ACTION_OPEN_DOCUMENT"))
+		        {
+		            //looks like permission was revoked.
+		            throw new DocumentAccessRevokedException();
+		        }
+		        throw;
+		    }
+			
 		}
 
 		public IWriteTransaction OpenWriteTransaction(IOConnectionInfo ioc, bool useFileTransaction)
@@ -267,7 +283,26 @@ namespace keepass2android.Io
 
 	}
 
-	class AndroidContentWriteTransaction : IWriteTransaction
+    public class DocumentAccessRevokedException : Exception
+    {
+        public DocumentAccessRevokedException()
+        {
+        }
+
+        public DocumentAccessRevokedException(string message) : base(message)
+        {
+        }
+
+        public DocumentAccessRevokedException(string message, Exception innerException) : base(message, innerException)
+        {
+        }
+
+        protected DocumentAccessRevokedException(SerializationInfo info, StreamingContext context) : base(info, context)
+        {
+        }
+    }
+
+    class AndroidContentWriteTransaction : IWriteTransaction
 	{
 		private readonly string _path;
 		private readonly Context _ctx;

src/Kp2aBusinessLogic/UiStringKey.cs

@@ -63,7 +63,8 @@ namespace keepass2android
 		AskDeletePermanentlyItems,
 		AskDeletePermanentlyItemsNoRecycle,
 		InOfflineMode,
-		DuplicateTitle,
+        DocumentAccessRevoked,
+        DuplicateTitle,
 		TemplateTitle_IdCard,
 		TemplateField_IdCard_Name,
 		TemplateField_IdCard_PlaceOfIssue,

src/keepass2android/Resources/values/strings.xml

@@ -403,6 +403,8 @@
   <string name="IconVisibilityInfo_Android8_btnSettings">Open settings</string>
   <string name="DontCare">I don\'t care</string>
 
+  <string name="DocumentAccessRevoked">The file is no longer accessible to Keepass2Android. Either it was removed or the access permissions have been revoked. Please use re-open the file, e.g. using Change database.</string>
+
 	<string name="PreloadDatabaseEnabled_title">Pre-load database file</string>
 	<string name="PreloadDatabaseEnabled_summary">Start background loading or downloading of the database file during password entry.</string>
 

src/keepass2android/app/App.cs

@@ -714,7 +714,10 @@ namespace keepass2android
 			string errorMessage = e.Message;
 			if (e is OfflineModeException)
 				errorMessage = GetResourceString(UiStringKey.InOfflineMode);
-			return errorMessage;
+		    if (e is DocumentAccessRevokedException)
+		        errorMessage = GetResourceString(UiStringKey.DocumentAccessRevoked);
+
+            return errorMessage;
 		}