[Android] StreamingAsset problems with XML files

Thanks to

saschandroid

who provided a very crucial piece of information, I was finally able to solve this one. Here is my solution and a few insights, that might help others who are stuck with the same problem.

First of: Make sure you actually have .xml-files and not .txt-files in your project. As arbitrary as that sounds, this can be easy to overlook, when you are testing on your PC. Because, when deserializing .txt-files on the PC, Unitys XMLSerializer is capable of interpreting these as if they were .xml-files. But once you switch over to Android this doesn't seem to work anymore. If you aren't sure, just double-click on the file and it should open in your standard-webbrowser, if your file really is an .xml-file.

Another thing to pay attention to is the top line in your .xml-file. To see that, open your file in any texteditor you want. Some web-browsers don't show it, if you try to open it that way.

 <?xml version="1.0" encoding="utf-8"?>

Make sure, that it says encoding = "utf-8" , so any phone anywhere can really interpret your .xml-file. If you do it like me and generate your .xml-files through code, make sure you use the Streamwriter-class instead of the Filewriter-class, to change your encoding to the desired encoding = "utf-8". Unfortunately the Streamwriter-class will always overwrite a file, that has the same name in your save-to-path, instead of creating a new one. So make sure your save-to-path really is unique, if you don't want to overwrite existing data. Example:

     XmlSerializer serializer = new XmlSerializer(typeof(Levels));
     var encoding = Encoding.GetEncoding("UTF-8");

     //we will use this to give our xml-file a unique number at the end to prevent it from overwriting an existing file
     int uniqueIndex = 1;
 
     //Path you want your xml-files to be saved to
     string newPath = "YOURPATH"+"FILENAME"+uniqueIndex.ToString() + ".xml";

     //if a file with your name is already there, generate a unique name        
     while(File.Exists(newPath))
     {
         uniqueIndex ++;
         newPath = "YOURPATH"+"FILENAME"+uniqueIndex.ToString() + ".xml";
     }

     StreamWriter stream = new StreamWriter(newPath, false, encoding);
     serializer.Serialize(stream, lvls);
     stream.Close();

And last, but certainly not least, use the MemoryStream-class to deserialize on Android. Your Code should look something like this:

 if (Application.platform == RuntimePlatform.Android)
 {
     string streamingAssetsPath =  Application.streamingAssetsPath;
     //Make sure your path doesn't miss any '/'
     string realPath = streamingAssetsPath + "YOURPATH" + "FILENAME" + ".xml";

     WWW reader = new WWW (realPath);
             
     while(!reader.isDone)
     {
         //wait for the reader to finish downloading        
     }
     XmlSerializer serializer = new XmlSerializer(typeof(Levels));

     MemoryStream stream = new MemoryStream(reader.bytes);
             
     if(stream != null)
     {
         lvls = serializer.Deserialize(stream) as Levels;    
     }
     stream.Close();
  }