在這里的fontString / fontString1就是當前設(shè)置的系統(tǒng)文字字號大小
UIFont *font = [UIFont preferredFontForTextStyle:UIFontTextStyleBody];
UIFontDescriptor *ctFont = font.fontDescriptor;
NSNumber *fontString = [ctFont objectForKey:@"NSFontSizeAttribute"];
NSNumber *fontString1 = [ctFont objectForKey:UIFontDescriptorSizeAttribute];
NSLog(@"%@:%@",fontString1,fontString);