如何设置UIPickerView选择指示器的样式？

Question

我想实现选择指标的风格如下图所示： -

以下是我的代码： -

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
    UILabel* tView = (UILabel*)view;
    if (!tView)
    {
        tView = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, pickerView.frame.size.width, pickerView.frame.size.height)];
        [tView setFont:[UIFont fontWithName:APP_FONT_OPENSANS_LIGHT size:18]];
        [tView setTextColor:[UIColor colorWithRed:65.0f/255.0f green:65.0f/255.0f blue:65.0f/255.0f alpha:1]];
        [tView setTextAlignment:NSTextAlignmentCenter];
        tView.numberOfLines=1;
    }
    // Fill the label text here
    tView.text=@"Hello Moto";
//    pickerView.subviews[1].backgroundColor = [UIColor whiteColor];
//    pickerView.subviews[2].backgroundColor = [UIColor whiteColor];

    return tView;
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{

    UILabel *labelSelected = (UILabel*)[pickerView viewForRow:row forComponent:component];
    labelSelected.layer.cornerRadius = 20.0f;
    [labelSelected setBackgroundColor:[UIColor whiteColor]];

}

它没有给我我想要的东西。任何解决方案都非常感谢。