[IOS]navigation bar 改变按钮和标题

1.改变按钮

在父页面：

UIBarButtonItem *backBtn = [[UIBarButtonItem alloc]init];
    backBtn.title = @"xxxx";
    self.navigationItem.backBarButtonItem = backBtn;

2.改变标题：

在子页面：

UINavigationItem *navItem = self.navigationItem;
navItem.title = @"My Device";

3.取消回退按钮

navItem.hidesBackButton = YES;

4.改变navigation bar颜色：

self.navigationController.navigationBar.barTintColor = [UIColor lightGrayColor];

5.设置back button事件

self.navigationItem.leftBarButtonItem = [[[UIBarButtonItem alloc]
                                              initWithTitle:@"返回"
                                              style:UIBarButtonItemStylePlain
                                              target:self
                                              action:@selector(GoBack:)]
                                              autorelease];