UINavigationController详解与使用(二)页面切换和segmentedController

UINavigationController详解与使用(一)添加UIBarButtonItem是上篇，我们接着讲UINavigationController的重要作用，页面的管理和切换。


运行效果图：
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1、RootView 跳到SecondView

首先我们需要新一个View。新建SecondView，按住Command键然后按N,弹出新建页面，我们新建SecondView

2、为Button 添加点击事件，实现跳转
在RootViewController.xib中和RootViewController.h文件建立连接
在RootViewController.m中实现代码，alloc一个SecondViewController，用pushViewController到navigationController中去，并为

SecondViewController这是title为    secondView.title =@"Second View"; 默认情况下，titie为下个页面返回按钮的名字。

- (IBAction)gotoSecondView:(id)sender {
    SecondViewController *secondView = [[SecondViewController alloc] init];
    [self.navigationController pushViewController:secondView animated:YES];
    secondView.title = @"Second View";
}

3.1、添加segmentedController
     在RootViewController.m的viewDidLoad添加如下代码:

 NSArray *array = [NSArray arrayWithObjects:@"鸡翅",@"排骨", nil];
    UISegmentedControl *segmentedController = [[UISegmentedControl alloc] initWithItems:array];
    segmentedController.segmentedControlStyle = UISegmentedControlSegmentCenter;

    [segmentedController addTarget:self action:@selector(segmentAction:) forControlEvents:UIControlEventValueChanged];
    self.navigationItem.titleView = segmentedController;

3.2[segmentedController addTarget:selfaction:的实现

-(void)segmentAction:(id)sender
{
    switch ([sender selectedSegmentIndex]) {
        case 0:
        {
            UIAlertView *alter = [[UIAlertView alloc] initWithTitle:@"提示" message:@"你点击了鸡翅" delegate:self  cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
            [alter show];

        }
        break;
    case 1:
        {
            UIAlertView *alter = [[UIAlertView alloc] initWithTitle:@"提示" message:@"你点击了排骨" delegate:self  cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
            [alter show];
        }
        break;
        
        default:
            break;
    }
}

4、自定义backBarButtonItem

左上角的返回上级View的barButtonitem的名字是上级目录的Title，如果title或者适合做button的名字，怎么办呢？我们可以自己定义
代码如下：

 UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"根视图" style:UIBarButtonItemStyleDone target:nil action:nil];
    self.navigationItem.backBarBu

我是新手，主意添加位置：RootViewControll.m中
  

- (void)viewDidLoad
{
    [super viewDidLoad];
    //add leftButton 添加左按钮
    UIBarButtonItem *leftButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:@selector(selectLeftAction:)];
    self.navigationItem.leftBarButtonItem = leftButton;
    
    // add rightButton 添加右按钮
    UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd  target:self action:@selector(selectRightAction:)];
    self.navigationItem.rightBarButtonItem = rightButton;
    
    
    // add backButton 添加返回按钮
    UIBarButtonItem *backButton = [[UIBarButtonItem alloc]initWithTitle:@"Root View" style:UIBarButtonItemStyleDone target:self action:nil];
    self.navigationItem.backBarButtonItem = backButton;
    
    //add SegmentedControl on Navigation  添加分段
    NSArray *array = [[NSArray alloc] initWithObjects:@"one",@"two" ,@"three",nil];
    UISegmentedControl *segmentdeController = [[UISegmentedControl alloc] initWithItems:array];
    segmentdeController.segmentedControlStyle = UISegmentedControlSegmentCenter;
    [segmentdeController addTarget:self action:@selector(segmentAction:) forControlEvents:UIControlEventValueChanged];
    self.navigationItem.titleView = segmentdeController;
    
    
    
    
}

5、自定义title
UINavigationController的title可以用别view替代，比如用UIButton UILable等，下面我用UIButton.
在SecondViewController.m中添加下面如下:

- (void)viewDidLoad
{
    [super viewDidLoad];
    UIButton *button = [UIButton buttonWithType: UIButtonTypeRoundedRect];
    [button setTitle: @"自定义title" forState: UIControlStateNormal];
    [button sizeToFit];
    self.navigationItem.titleView = button;}