将UIPickerView添加到UIAlertController

Question

我正在尝试向UIPickerVivew添加UIAlertController。我试着做以下事情：

- (void)alertPickerView    
{    
    UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:@"Title" delegate:nil    
                                                    cancelButtonTitle:nil    
                                               destructiveButtonTitle:nil
                                                        otherButtonTitles:nil, nil];
    actionSheet.delegate = self;
    UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 0, 320, 200)];
    pickerView.delegate = self;
    pickerView.showsSelectionIndicator = YES;
    [actionSheet addSubview:pickerView];
}

当我调用该方法时，pickerView和actionSheet没有出现。

（我宁愿UIAlertController，但如果不可能，我会选择actionsheet。）