avoid potential crashes when opening child databases (caused by network on main thread or URLs without username/password), fixes https://github.com/PhilippC/keepass2android/issues/728

src/AndroidFileChooserBinding/AndroidFileChooserBinding.csproj

@@ -52,11 +52,9 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>
-    <LibraryProjectZip Include="..\java\android-filechooser-AS\app\build\outputs\aar\android-filechooser-release.aar">
-      <Link>Jars\android-filechooser-release.aar</Link>
-    </LibraryProjectZip>
     <None Include="Jars\AboutJars.txt" />
     <None Include="Additions\AboutAdditions.txt" />
+    <LibraryProjectZip Include="Jars\android-filechooser-debug.aar" />
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>

src/java/JavaFileStorage/app/src/main/java/keepass2android/javafilestorage/WebDavStorage.java

@@ -71,9 +71,18 @@ public class WebDavStorage extends JavaFileStorageBase {
 
         String scheme = filename.substring(0, filename.indexOf("://"));
         filename = filename.substring(scheme.length() + 3);
-        String userPwd = filename.substring(0, filename.indexOf('@'));
+        int idxAt = filename.indexOf('@');
-        ci.username = decode(userPwd.substring(0, userPwd.indexOf(":")));
+        if (idxAt >= 0)
-        ci.password = decode(userPwd.substring(userPwd.indexOf(":") + 1));
+        {
+            String userPwd = filename.substring(0, idxAt);
+            int idxColon = userPwd.indexOf(":");
+            if (idxColon >= 0);
+            {
+                ci.username = decode(userPwd.substring(0, idxColon));
+                ci.password = decode(userPwd.substring(idxColon + 1));
+            }
+        }
+
         ci.URL = scheme + "://" +filename.substring(filename.indexOf('@') + 1);
         return ci;
     }

src/keepass2android/KeeAutoExec.cs

@@ -335,9 +335,18 @@ namespace keepass2android
 
         private static bool CheckFileExsts(IOConnectionInfo ioc)
         {
+
             try
             {
                 var fileStorage = App.Kp2a.GetFileStorage(ioc);
+
+                //we're assuming that remote files always exist (if we have a file storage, i.e. we check after receiving a file storage)
+                //The SkipIfNotExists switch only makes sense for local files, because remote files either exist for all devices or none
+                //(Ok, there are exceptions like files available in a (W)LAN. But then we still have the device switch and caches.)
+                //We cannot use OpenFileForRead on remote storages because this method is called from the main thread.
+                if (!ioc.IsLocalFile())
+                    return true;
+
                 using (var stream = fileStorage.OpenFileForRead(ioc))
                 {
                 }