CTFontManagerRegisterFontsForURL not work on device

Question

I am trying to use CTFontDescriptorMatchFontDescriptorsWithProgressHandler to download a font. As same as the example provided by Apple: https://developer.apple.com/library/ios/samplecode/DownloadFont/Listings/DownloadFont_ViewController_m.html

It works fine, and I can display the downloaded font in my application, but after I restart my application I can not create the UIFont with fontWithName:size:, and [UIFont familyNames] does not include the downloaded font. To solve this problem, I record the font path and use CTFontManagerRegisterFontsForURL to register the font when start the application. After doing this, everything is OK on simulator, but not works on device!!! Help!!!

Answer 1

Finally, I found the problem is that CTFontManagerRegisterFontsForURL will fail when the font file url is something like: /var/mobile/.../XXX.ttc, and after I fixed the url to be file:///var/mobile/.../XXX.ttc, everything will be OK.