以编程方式更改UIBarButtonItem的标识符属性

UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd 
                                                                           target:self 
                                                                           action:@selector(doAddAction:)];

如果你想要一个按钮样式:带边框和标识符:相机使用

UIBarButtonItem *btn;
btn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCamera target:self action:@selector(shotAction:)];
btn.style=UIBarButtonItemStyleBordered;

UIBarButtonItem *barButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction
                                                              target:self
                                                              action:@selector(buttonClickedAction:)];

self.navigationItem.rightBarButtonItem = barButton;