ios - How do you make an UIPickerView component wrap around?

Question

I would like to show a set of consecutive numbers in a UIPickerView component but have it wrap around like the seconds component of the Clock->Timer application. The only behavior I can enable looks like the hours component of the Timer application, where you can scroll in only one direction.

question from:https://stackoverflow.com/questions/214441/how-do-you-make-an-uipickerview-component-wrap-around

Answer 1

It's just as easy to set the number of rows to a large number, and make it start at a high value, there's little chance that the user will ever scroll the wheel for a very long time -- And even then, the worse that will happen is that they'll hit the bottom.

- (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;
    // ...
}