CODEWITHSUNDEEP
objective-cioscocoa
Roddy
Roddy

Reputation: 2048

UIPickerView - getting the selection from the delegate

I am learning the use of UIPickerView objects and creating one programatically. Given that it uses a delegate to call if a selection is made; what is the standard practise for getting that information to the main view controller that instantiated the picker?

I am thinking that I will use a selector to allow the delegate to send the selected row to the view controller; is there a better way?

Any assistance from someone who uses these objects regularly would be appreciated.

Upvotes: 1

Views: 202

Answers (2)

jmstone617
jmstone617

Reputation: 5707

Typically, your UIViewController that instantiated the UIPickerView will also act as its delegate (and datasource). In this case, you would assign your view controller to be the delegate of the picker, such as

[myPickerView setDelegate:self];

Then, you'll implement the method - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component inside your view controller. When you assign an object to be the delegate of another object, you're saying "Hey, this object knows what to do when it gets sent these delegate messages". In your case, you're saying "My main controller knows what to do when the picker sends it the didSelectRow:inComponent: message".

In doing this, you won't need to do any of that use-a-selector-to-allow-the-delegate-to-send-the-selected-row-to-the-view-controller nonsense. That is the whole point of the delegate! UIPickerView is "delegating" work to some other object (your controller) that knows what to do with the information contained within the selected row of the picker.

Upvotes: 1

Peter Warbo
Peter Warbo

Reputation: 11728

Implement the delegate method - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component so that whenever a row is selected it will call this method.

You can do something like this:

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

    NSLog(@"row %d selected in component %d", row, component);
}

Upvotes: 1

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