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.

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;     // ... }