改变字体

迅速

//System Font
textView.font = UIFont.systemFont(ofSize: 12)

//Font of your choosing
textView.font = UIFont(name: "Font Name", size: 12)

Objective-C

//System Font
textView.font = [UIFont systemFontOfSize:12];

//Font of your choosing
textView.font = [UIFont fontWithName:@"Font Name" size:12];