Programmatically trigger UIButton action . Calling Method from button @selector.

- (void)sendActionsForControlEvents:(UIControlEvents)controlEvents

Parameters:  controlEvents 

A bitmask whose set flags specify the control events for which action messages are sent. See Control Events for bitmask constants.

Description:Sends action messages for the given control events.UIControl implements this method to send all action messages associated with controlEvents, 

repeatedly invoking sendAction:to:forEvent: in the process. 

The list of targets and actions it looks up is constructed from prior invocations of addTarget:action:forControlEvents:.

Eg:

To call a method  MySecretMethod in newViewController 

[newViewController.button  addTarget: self 

                                              action: @selector (MySecretMethod)  

                                              forControlEvents:  UIControlEventTouchUpInside];

Method 1: declare MySecretMethod in .h of newViewController and call it

 by its object (so it wont be secret as can be accessed from anywhere.)

                 [newViewController MySecretMethod];

Method 2: declare button in .h of newViewController and call button action using following statement

[newViewController.button sendActionsForControlEvents: UIControlEventTouchUpInside];

Looping SuperView 

You can add or change the button action by looping superview view using addTarget:action:forControlEvents:

for(UIButton *aButton in self.view.subviews){

        if([aButton isKindOfClass:[UIButton class]]){

            [aButton addTarget: self 

                     action:@selector(buttonClick:) 

                     forControlEvents: UIControlEventTouchUpInside];

             }

    }

Read More:

UIButton

UIControl