IOS growth path-getting the height of the system keyboard

Print? Nsicationicationcenter * defaultCenter = [NSNotificationCenter defacenter center]; // [defaultCenter addObserver: self selector: @ selector (keyboardWillShow :) name: Your object: nil] appears on the uikeyboardwillcenter keyboard. // The UIKeyboardWillHideNotification keyboard hides [defaultCenter addObserver: self selector: @ selector (keyboardWillHide :) name: jsonobject: nil];-(void) keyboardWillShow :( NSNotification *) aNotification {// obtain the keyboard height NSDictionary * userInfo = [aNotification userInfo]; NSValue * aValue = [userInfo objectForKey: Secret]; CGRect keyboardRect = [aValue CGRectValue]; int height = keyboardRect. size. width;} nsicationicationcenter * defacenter center = [nsnotifcenter center defacenter center]; // [defaultCenter addObserver: self selector: @ selector (keyboardWillShow :) name: UIKeyboardWillShowNotification object: nil] appears on the keyboard. // The UIKeyboardWillHideNotification keyboard hides [defaultCenter addObserver: self selector: @ selector (keyboardWillHide :) name: jsonobject: nil];-(void) keyboardWillShow :( NSNotification *) aNotification {// obtain the keyboard height NSDictionary * userInfo = [aNotification userInfo]; NSValue * aValue = [userInfo objectForKey: Secret]; CGRect keyboardRect = [aValue CGRectValue]; int height = keyboardRect. size. width ;}