iOS——实现调用拨打电话

NSMutableString * str=[[NSMutableString alloc] initWithFormat:@"tel:%@",@"183********"];

    UIWebView * callWebview = [[UIWebView alloc] init];

    [callWebview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:str]]];

    [self.view addSubview:callWebview];