How to save a file on Android? (Firemonkey)

Instead of using System.SysUtils.PathDelim, you may use

System.IOUtils.TPath.Combine(System.IOUtils.tpath.getdocumentspath,'test.txt');

Combine chooses between the windows \ and the Linux /

System.IOUtils must be used in this line instead of setup in the uses clause because there are probably more Tpath initials.

According to the document Creating an Android App, get the documents path like this:

System.IOUtils.TPath.GetDocumentsPath + System.SysUtils.PathDelim + 'myfile';