Observing change in UIDatePicker

I noticed that there is no delegate to observe changes in UIDatePicker. Is there a way to detect when a change is made in the picker without confirming anything, like the moment it spins and lands on a new number I want to be able to detect that. I thought about key value observing, but I don't think there's a property that changes on the spot

4 Answers

You need to add to your UIDatePicker the UIControlEventValueChanged event to handle date changes:

[myDatePicker addTarget:self action:@selector(dateIsChanged:) forControlEvents:UIControlEventValueChanged]; 

Then the implementation:

- (void)dateIsChanged:(id)sender{ NSLog(@"Date changed"); } 

Go to IB and drag from the UIDatePicker to your .h file. Then select

Handle this however you want in your .m file; XCode will add the method below for you.

Swift 4.2 | Xcode 10.1

@objc func handleDatePicker(_ datePicker: UIDatePicker) { textField.text = datePicker.date.formatted } override func viewDidLoad() { super.viewDidLoad() datePicker.addTarget(self, action: #selector(handleDatePicker), for: .valueChanged) } 

extension Date { static let formatter: DateFormatter = { let formatter = DateFormatter() formatter.dateFormat = "EEEE, dd MMM yyyy HH:mm:ss Z" return formatter }() var formatted: String { return Date.formatter.string(from: self) } } 

Here is a proposal for a KVO-compliant date picker:

@interface LNKVODatePicker : UIDatePicker @end @implementation LNKVODatePicker - (void)willMoveToWindow:(UIWindow *)newWindow { [super willMoveToWindow:newWindow]; [self removeTarget:self action:@selector(_didChangeDate) forControlEvents:UIControlEventValueChanged]; if(newWindow != nil) { [self addTarget:self action:@selector(_didChangeDate) forControlEvents:UIControlEventValueChanged]; } } - (void)dealloc { [self removeTarget:self action:@selector(_didChangeDate) forControlEvents:UIControlEventValueChanged]; } - (void)_didChangeDate { [self willChangeValueForKey:@"date"]; [self didChangeValueForKey:@"date"]; } @end