How can I reset my UI when the user presses a button?

I have 开发者_运维百科1 scrollview that contain 18 buttons.

1) when a user taps on any button, a button is added to a second UIScrollView.

2) Then, when a user taps on that button on second scrollview the button is removed from second scrollview.

both uiscrollviews contain a list of their buttons.

Afree both of these steps, I have to reload my scrollview.

Can I do the same task by adding observer, so that it will automatically reload when any action done on button, and if yes then how?

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You should look into the NSNotificationCenter class and notifications for this. You can post a notification and have the appropriate class respond to that notification. Here is a reference from Apple:

Basically, your parent view will add itself as an observer of a notification. You generally define the constant that represents your notification. Then, add code to your buttons or scroll views to post the Notification at the appropriate time(s).