Xcode Objective-C: Download a custom font and display it in a UILabel - objective-c

Question

First of all: Is it possible to download a custom font and display it in a UILabel?
I'm using this code to download a custom font from internet and display it in a UILabel but it does not work.
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize txt_UserName;
- (void)viewDidLoad {
[super viewDidLoad];
// 1
NSString *dataUrl = #"https://dl.dafont.com/dl/?f=stars_fighters";
NSURL *url = [NSURL URLWithString:dataUrl];
// 2
NSURLSessionDataTask *downloadTask = [[NSURLSession sharedSession] dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
// 4: Handle response here
if (error == nil) {
NSLog(#"no error!");
if (data != nil) {
NSLog(#"There is data!");
[self loadFont:data];
}
} else {
NSLog(#"%#", error.localizedDescription);
}
}];
// 3
[downloadTask resume];
}
- (void)loadFont:(NSData *)data
{
NSData *inData = data;
CFErrorRef error;
CGDataProviderRef provider = CGDataProviderCreateWithCFData((CFDataRef)data);
CGFontRef font = CGFontCreateWithDataProvider(provider);
if(!CTFontManagerRegisterGraphicsFont(font, &error)){
CFStringRef errorDescription = CFErrorCopyDescription(error);
NSLog(#"Failed to load font: %#", errorDescription);
// CFRelease(errorDescription);
}
// CFRelease(font);
// CFRelease(provider);
CTFontRef ctFont = CTFontCreateWithGraphicsFont(font, 30, NULL, NULL);
UIFont *uiFont = CFBridgingRelease(ctFont);
dispatch_async(dispatch_get_main_queue(), ^{
[self.txt_UserName setFont:uiFont];
});
[self fontTest];
}
- (void)fontTest
{
NSArray *fontFamilies = [UIFont familyNames];
for (int i = 0; i < [fontFamilies count]; i++) {
NSString *fontFamily = [fontFamilies objectAtIndex:i];
NSArray *fontNames = [UIFont fontNamesForFamilyName:[fontFamilies objectAtIndex:i]];
NSLog (#"%#: %#", fontFamily, fontNames);
}
}
#end
Anyway I'm getting this error: Failed to load font: The operation couldn’t be completed. Invalid argument
At the place of the custom font I get a default iOS font.

Answer 1

Of course it's possible to download a custom font and display it in a UILabel,here is my code that works well:
step 1: Assuming the font file has been saved in the sandbox path Documents / StarsFighters.ttf, load the font and get font name（in YOUR_CLASS .m file）:
+ (NSString *)loadFontAndReturnFontName {
NSString *imgFilePath = [NSString stringWithFormat:#"%#/Documents/StarsFighters.ttf",NSHomeDirectory()];
NSURL *fontUrl = [NSURL fileURLWithPath:imgFilePath];
CGDataProviderRef fontDataProvider = CGDataProviderCreateWithURL((__bridge CFURLRef)fontUrl);
CGFontRef fontRef = CGFontCreateWithDataProvider(fontDataProvider);
CGDataProviderRelease(fontDataProvider);
CTFontManagerRegisterGraphicsFont(fontRef, NULL);
NSString *fontName = CFBridgingRelease(CGFontCopyPostScriptName(fontRef));
return fontName;
}
step2: use custom font
NSString *fontname = [YOUR_CLASS loadFontAndReturnFontName];
//fontname is #"StarsFighters",best set it to a global variable or save it
YOUR_LABEL.font = [UIFont fontWithName:fontname size:18.0];