UIAlertController* alertController=[UIAlertController alertControllerWithTitle:@"您的选择" message:[NSString stringWithFormat:@"%@",sender] preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* defaultAction=[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
}];//一个UIAlertAction 是UIAlertController的一个按钮
[alertController addAction:defaultAction];
[self presentViewController:alertController animated:YES completion:nil];
