UINavigationItem:添加按钮

如何在navigationItem中添加新按钮？需要在右侧按钮附近：

左右按钮：

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:_cancelButton];
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:_shareButton];

再添加一个？

有很多方法可以实现在右侧添加一个按钮，我认为最简单的方法：

UIView *buttonView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 44)];

UIButton *exampleButton1 = [UIButton buttonWithType:UIButtonTypeCustom];
exampleButton1.frame = CGRectMake(0, 2, 30, 40);
[exampleButton1 addTarget:self action:@selector(FirstMethod) forControlEvents:UIControlEventTouchUpInside];
[exampleButton1 setImage:[UIImage imageNamed:@"image1.png"] forState:UIControlStateNormal];
[buttonView addSubview:exampleButton1];
UIButton *exampleButton2 = [UIButton buttonWithType:UIButtonTypeCustom];
exampleButton2.frame = CGRectMake(70, 2, 30, 40);
[exampleButton2 addTarget:self action:@selector(Second method) forControlEvents:UIControlEventTouchUpInside];
[exampleButton2 setImage:[UIImage imageNamed:@"image2.png"] forState:UIControlStateNormal];

[buttonView addSubview:exampleButton2];

 self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:buttonView];

放中间的话可以用

self.navigationItem.titleView=.....