设置上一级controller的backBarButtonItem

 

设置上一级controller的backBarButtonItem.

self.navigationItem.backBarButtonItem= [[UIBarButtonItem alloc]initWithTitle:@"返回"
                                                                           style:UIBarButtonItemStylePlain
                                                                          target:nil                                                                       
                                                                           action:@selector(back_event:)];