NSURL *url = [NSURL URLWithString:@"tel://18612345678"];
if ([[UIApplication sharedApplication] canOpenURL:url]) {
[[UIApplication sharedApplication] openURL:url];
}
@"tel://18612345678"
@"mailto:12345678@gmail.com"
@"facetime:12345678@gmail.com"
@"https://itunes.apple.com/cn/app/wei-xin/id414478124"
@"http://maps.apple.com/?ll=114.06667,22.61667"
参考：
https://developer.apple.com/library/ios/featuredarticles/iPhoneURLScheme_Reference/Introduction/Introduction.html#/apple_ref/doc/uid/TP40007891-SW1
