How to detect changes on UIPickerView?

Question

I want to detect changes of UIPickerView value.

If UIPickerView respond to addTarget I used a code like this:

-(void) valueChange:(id)sender {
    change = YES;
} 

UIPickerView *questionPicker = [[UIPickerView alloc] init]; 
[questionPicker addTarget:self action:@selector(valueChange:) forControlEvents:UIControlEventValueChanged];

How can I do same things but in a correct way ?

score 61 · Answer 1 · answered Apr 02 '10 at 08:57

61

If you look at the UIPickerViewDelegate it has:

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

Simply set your picker views delegate and implement this.

answered Apr 02 '10 at 08:57

Kevin Sylvestre

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2

Is it possible to update the label in realtime while the picker view is scrolling? I mean it takes time. But the requirement is to get it to work as it works in Android.(Which is flawless) – Ritesh.mlk Sep 01 '18 at 11:26
Old question, but my advice here is, don't try to force iOS to be Android as users of either platform may be used to different functionality. Neither is 'right' or 'wrong', just different. – Ash Jul 16 '20 at 13:27

score 6 · Answer 2 · answered Apr 02 '10 at 08:58

6

UIPickerViewDelegate has pickerView:didSelectRow:inComponent:

answered Apr 02 '10 at 08:58

gammelgul

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score 2 · Answer 3 · answered May 24 '19 at 05:55

Swift 4: Implement picker view delegates:

optional public func pickerView(_ pickerView: UIPickerView, titleForRow row: 
   Int, forComponent component: Int) -> String?

Example:

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, 
forComponent component: Int) -> String? {
            let value = dummyListArray[row]
            if value == "someText"{
              //Perform Action
            }
            return value
}

Or

optional public func pickerView(_ pickerView: UIPickerView, didSelectRow row: 
   Int, inComponent component: Int)

Example:

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, 
inComponent component: Int) {
            let value = dummyListArray[row]
            if value == "someText"{
              //Perform Action
            }        
}

score 1 · Answer 4 · answered Mar 07 '19 at 08:34

1

Better override this function

public override func selectedRow(inComponent component: Int) -> Int {
  let index = super.selectedRow(inComponent: component)
  //call closure or delegate as you want
  return index
}

in UIPickerView class to observe changing in realtime.

answered Mar 07 '19 at 08:34

tylerlantern

85
7

Not worked for me. It is just called on scroll stops. – Douglas Nassif Roma Junior May 30 '19 at 23:09

score 0 · Answer 5 · edited Feb 08 '21 at 10:22

0

You have to use picker view delegate method:

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
}

edited Feb 08 '21 at 10:22

aturan23

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answered Feb 06 '20 at 09:51

Haya Hashmat

137
10

score 0 · Answer 6 · answered Jan 15 '21 at 03:12

0

func pickerView(UIPickerView, didSelectRow: Int, inComponent: Int)

Called by the picker view when the user selects a row in a component.

That allows for instance to update a textfield when selection change, just on the release of a finger.

answered Jan 15 '21 at 03:12

incredever

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How to detect changes on UIPickerView?

6 Answers6