参考文章：原文🔗

iOS可以动态的为系统下载字体，这些字体都下载到了系统的/private/var/mobile/Library/Assets/com_apple_MobileAsset_Font/目录下，并且可以被其他应用公用。当然，问题是应用的大小倒是没变，而你的手机空间在不知不觉中就变小了。\-.-/～

来看下如何实现动态下载：

CTFontDescriptorRef descRef = CTFontDescriptorCreateWithAttributes((__bridge CFDictionaryRef)@{(NSString *)kCTFontNameAttribute: fontName});
    NSArray *descs = @[(__bridge id)descRef];
    
    CTFontDescriptorMatchFontDescriptorsWithProgressHandler((CFArrayRef)descs, NULL, ^bool(CTFontDescriptorMatchingState state, CFDictionaryRef  _Nonnull progressParameter) {
        
        if (state == kCTFontDescriptorMatchingWillBeginDownloading) {
            NSLog(@"开始下载");
        } else if (state == kCTFontDescriptorMatchingDownloading) {
            double progressValue = [[(__bridge NSDictionary *)progressParameter objectForKey:(id)kCTFontDescriptorMatchingPercentage] doubleValue];
            NSLog(@"下载进度:%0.2lf",progressValue);
        } else if (state == kCTFontDescriptorMatchingDidFinishDownloading) {
            NSLog(@"下载完成");
            
            dispatch_async(dispatch_get_main_queue(), ^{
                self.label.font = [UIFont fontWithName:fontName size:12];
            });
        } else if (state == kCTFontDescriptorMatchingDidBegin) {
            NSLog(@"开始");
        }
        
        return YES;
    });

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