How we set or get focus to any control - and leave the focus in Cocoa

How we set 开发者_Go百科or get focus on any control in cocoa. like setfirstresponder

We have 2 control A and B, A is firstresponder After action I want to set focus ob B control

and also how we get focus on a particular control and how we notify that leave focus..... I need it in validation .... I want to force user to fill a textfield and then go to next field..something like this

Thanks Deepika

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You should use NSWindow’s makeFirstResponder: to change the current first responder. See the NSResponder class reference for details on this.

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For validation, the -becomeFirstResponder and -resignFirstResponder methods can be overridden.

More details in the documentation