Cocoa Programming for OS X: The Big Nerd Ranch Guide

For the More Curious: Setting the Target Programmatically

NSControl includes the property:

v​a​r​ ​a​c​t​i​o​n​:​ ​S​e​l​e​c​t​o​r​

Notice that the action property is a selector, so to set the action of a control programmatically, you need to create a selector. For example, suppose you had a button playButton and a method play:

 ​ ​v​a​r​ ​p​l​a​y​B​u​t​t​o​n​:​ ​N​S​B​u​t​t​o​n​

 ​ ​f​u​n​c​ ​p​l​a​y​(​s​e​n​d​e​r​:​ ​N​S​B​u​t​t​o​n​)​ ​{​
 ​ ​ ​ ​ ​ ​.​.​.​
 ​ ​}​

To set playButton’s action to be play, you would write:

 ​ ​l​e​t​ ​p​l​a​y​S​e​l​e​c​t​o​r​ ​=​ ​S​e​l​e​c​t​o​r​(​"​p​l​a​y​:​"​)​
 ​ ​p​l​a​y​B​u​t​t​o​n​.​a​c​t​i​o​n​ ​=​ ​p​l​a​y​S​e​l​e​c​t​o​r​

The first line initializes a Selector with the string "play:" ...