make loading of databases through third party app possible again (Android < 7) or hide third party app (Android >= 7)

src/keepass2android/FileStorageSelectionActivity.cs

@@ -74,7 +74,7 @@ namespace keepass2android
 				}
 					
 
-				if (context.Intent.GetBooleanExtra(AllowThirdPartyAppGet, false))
+				if ((context.Intent.GetBooleanExtra(AllowThirdPartyAppGet, false)) && (Util.ActionGetContentAvailable))
 					_displayedProtocolIds.Add("androidget");
 				if (context.Intent.GetBooleanExtra(AllowThirdPartyAppSend, false))
 					_displayedProtocolIds.Add("androidsend");

src/keepass2android/Utils/Util.cs

@@ -200,8 +200,10 @@ namespace keepass2android
 		/// is more for one-time access, but therefore allows possibly more available sources.</param>
 		public static void ShowBrowseDialog(Activity activity, int requestCodeBrowse, bool forSaving, bool tryGetPermanentAccess)
 		{
-			var loadAction = IsKitKatOrLater ? 
-							Intent.ActionOpenDocument : Intent.ActionGetContent;
+			var loadAction = (tryGetPermanentAccess && IsKitKatOrLater) || !ActionGetContentAvailable
+				? Intent.ActionOpenDocument
+				: Intent.ActionGetContent;
+
 			if ((!forSaving) && (IsIntentAvailable(activity, loadAction, "*/*", new List<string> { Intent.CategoryOpenable})))
 			{
 				Intent i = new Intent(loadAction);
@@ -230,6 +232,12 @@ namespace keepass2android
 			}
 		}
 
+		public static bool ActionGetContentAvailable
+		{
+			//https://commonsware.com/Android/previews/appendix-b-android-70
+			get { return ((int) Build.VERSION.SdkInt < 24); }
+		}
+
 		public static bool IsKitKatOrLater
 		{
 			get { return (int)Build.VERSION.SdkInt >= 19; }