如何使 UIPickerView 组件环绕？

我想在 UIPickerView 组件中显示一组连续数字，但让它像 Clock->Timer 应用程序的秒组件一样环绕。我可以启用的唯一行为类似于计时器应用程序的小时组件，您只能在一个方向上滚动。

将行数设置为较大的数字并使其以较高的值开始也很容易，用户不太可能长时间滚动滚轮 - 即便如此，情况也会更糟发生的情况是他们会触底。

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    // Near-infinite number of rows.
    return NSIntegerMax;
}

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    // Row n is same as row (n modulo numberItems).
    return [NSString stringWithFormat:@"%d", row % numberItems];
}

- (void)viewDidLoad {
    [super viewDidLoad];

    self.pickerView = [[[UIPickerView alloc] initWithFrame:CGRectZero] autorelease];
    // ...set pickerView properties... Look at Apple's UICatalog sample code for a good example.
    // Set current row to a large value (adjusted to current value if needed).
    [pickerView selectRow:currentValue+100000 inComponent:0 animated:NO];
    [self.view addSubview:pickerView];
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSInteger actualRow = row % numberItems;
    // ...
}