I can't use application simplified chinese font file under Windows. This is because after I add the font file using QFontDatabase::addApplicationFont(), the font family name returned by QFontDatabase::applicationFontFamilies() is an english name, but the internally registered font family name is a localized version name. It will fail to use the english name to access the font.
The sample program to reproduce this issue is attached. Before run the program, copy the attached test.tff font file to D:/test.tff, then run the program and you can see the character is not rendered in the font family I choose.