iOS 实现拨打电话

 // 电话号码
    NSMutableString *str=[[NSMutableString alloc] initWithFormat:@"tel:%@",@"18612346979"];
    UIWebView *callWebview = [[UIWebView alloc] init];
    [callWebview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:str]]];
    [self.view addSubview:callWebview];