http://blog.csdn.net/ouy_huan/article/details/30506925 借鉴于此，谢谢
1、这种方法，打完电话后还会回到原来的程序，也会弹出提示，推荐这种
NSMutableString * str=[[NSMutableString alloc] initWithFormat:@"tel:%@",@"182xxxxxxxx"];
UIWebView * callWebview = [[UIWebView alloc] init];
[callWebview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:str]]];
[self.view addSubview:callWebview];
2、这种方法，挂断电话会在原来的应用，而且是直接拨打，不弹出提示
NSMutableString * str=[[NSMutableString alloc] initWithFormat:@"tel:%@", @"电话号码"];
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:str]];
此方法可以自己定义提示信息：
UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:[NSString stringWithFormat:@"拨打该电话按照正常资费由运营商收取：%@", @"182xxxxxxxx"] preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
[alert dismissViewControllerAnimated:YES completion:^{
NSLog(@"取消拨打电话");
}];
}];
UIAlertAction *action2 = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
NSMutableString * str=[[NSMutableString alloc] initWithFormat:@"tel:%@", @"182xxxxxxxx"];
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:str]];
}];
[alert addAction:action1];
[alert addAction:action2];
[self presentViewController:alert animated:YES completion:^{
NSLog(@"弹出拨打电话号码弹框");
}];
3,这种方法也会回去到原来的程序里（注意这里的telprompt），也会弹出提示
NSMutableString * str=[[NSMutableString alloc] initWithFormat:@"telprompt://%@", @"182xxxxxxxx"];
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:str]];
