ios – Swift 2中没有关于segue的后退按钮

override func prepareForSegue(segue: UIStoryboardSegue,sender: AnyObject?) {
    // Get the new view controller using [segue desTinationViewController].
    // Pass the SELEcted object to the new view controller.
    if segue.identifier == "showExercise" {
        if let nav = segue.desTinationViewController as? UINavigationController {
            if let exercisesController = nav.topViewController as? ExercisesController {
                let cell = sender as! WorkoutCell
                if let workout = cell.name!.text {
                    exercisesController.exercises = Workouts[workout]!
                    exercisesController.navigationItem.title = workout
                }
            }
        }
    }
}

之前,父segue的后退按钮用于自动填充.现在,我得到的只是儿童导航vc中的标题