UINavigationController 基本用法

#import "MainViewController.h"
#import "SecondViewController.h"
@interface MainViewController ()<UINavigationControllerDelegate,UINavigationBarDelegate>

@end

@implementation MainViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    
    //设置导航栏标题，上下的标题都变（tabbar的也改变）
//    self.title = @"首页";
    
    //只有导航栏的标题改变
    self.navigationItem.title = @"Hello";
    
    //标题上面的小标题(导航栏高度会改变)
//    self.navigationItem.prompt = @"Hello!";

 //导航栏隐藏 导航栏是唯一的
//    self.navigationController.navigationBarHidden = YES ;

    //导航栏的背景颜色，如果设置颜色，模糊效果就会消失
    self.navigationController.navigationBar.barTintColor = [UIColor purpleColor];
    
    //导航栏的透明度(模糊效果)
    /*
     模糊效果打开：视图的坐标原点是屏幕的左上角
     模糊效果关闭：视图的坐标原点是导航栏的左下角
     导航栏高度（包含状态栏）64   状态栏高度是 20
     */
    self.navigationController.navigationBar.translucent = NO ;  //关闭透明度 （默认是打开的）
    
    /*
    
    //导航栏的背景图片
    //高度64  包括状态栏的高度 （图片320 * 64）
    
    [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"NavBar_64.png"] forBarMetrics:UIBarMetricsDefault];
    
    
    // 44 不包括状态栏  （图片320 * 44）
    [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"NavBar_44.png"] forBarMetrics:UIBarMetricsDefault];
    
    
    // 30 平铺 铺满导航栏和状态栏  （图片320 * 30）
    [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"NavBar_30.png"] forBarMetrics:UIBarMetricsDefault];
    
    */
    
    
    //self.navigationItem  每个页面显示在导航栏上的信息
    //系统自带的样式·
    /*
     UIBarButtonSystemItemDone,
     UIBarButtonSystemItemCancel,
     UIBarButtonSystemItemEdit,
     UIBarButtonSystemItemSave,
     UIBarButtonSystemItemAdd,
     UIBarButtonSystemItemFlexibleSpace,
     UIBarButtonSystemItemFixedSpace,
     UIBarButtonSystemItemCompose,
     UIBarButtonSystemItemReply,
     UIBarButtonSystemItemAction,
     UIBarButtonSystemItemOrganize,
     UIBarButtonSystemItemBookmarks,
     UIBarButtonSystemItemSearch,
     UIBarButtonSystemItemRefresh,
     UIBarButtonSystemItemStop,
     UIBarButtonSystemItemCamera,
     UIBarButtonSystemItemTrash,
     UIBarButtonSystemItemPlay,
     UIBarButtonSystemItemPause,
     UIBarButtonSystemItemRewind,
     UIBarButtonSystemItemFastForward,
     */
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemSearch target:self action:@selector(itemAction:)];
    
    
    /*
    //自定义文字标题的BarButtonItem （单个）
    self.navigationItem.leftBarButtonItem =[[UIBarButtonItem alloc]initWithTitle:@"点击" style:UIBarButtonItemStylePlain target:self action:@selector(itemAction:)];
    
    
    //自定义多个BarButtonItem 加在leftItem （多个）
        UIBarButtonItem *leftItem1 = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemSave target:self action:@selector(itemAction:)];
    //
         UIBarButtonItem *leftItem2 = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(itemAction:)];
    //
    //    //同时添加多个BarButtonItem
        self.navigationItem.leftBarButtonItems = @[leftItem1,leftItem2];
    
    */
    
    
    /*
    //自定义左右BarButtonItem
    UIButton *rightButton = [UIButton buttonWithType:UIButtonTypeCustom];
    rightButton.frame = CGRectMake(0, 0, 28, 28);
    [rightButton setImage:[UIImage imageNamed:@"iconfont-card-1"] forState:UIControlStateNormal];
    [rightButton addTarget:self action:@selector(Action:) forControlEvents:UIControlEventTouchUpInside];
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:rightButton];
    
    
    UIButton *leftButton = [UIButton buttonWithType:UIButtonTypeCustom];
    leftButton.frame = CGRectMake(0, 0, 28, 28);
    [leftButton setImage:[UIImage imageNamed:@"iconfont-card-1"] forState:UIControlStateNormal];
    [leftButton addTarget:self action:@selector(Action:) forControlEvents:UIControlEventTouchUpInside];
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:leftButton];

     */
    
    
    
    //渲染为原图  imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithImage:[[UIImage imageNamed:@"iconfont-card-1.png"]imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal] style:UIBarButtonItemStylePlain target:self action:@selector(rightAction:)];
    
    //中间的titleView  可以自定义一个view，label都可以
    self.navigationItem.titleView = [[UISegmentedControl alloc]initWithItems:@[@"控件一",@"控件二"]];
    
    /*
    //导航栏上的原色颜色
    self.navigationController.navigationBar.tintColor = [UIColor redColor];
    
    //返回上一控制器
    [self.navigationController popViewControllerAnimated:YES];
    //返回某一控制器
    [self.navigationController popToViewController:[[UIViewController alloc] init] animated:YES];
    //返回到根视图
    [self.navigationController popToRootViewControllerAnimated:YES];
    //B pop 返回A后，B是否释放要看之后的代码是否再次使用了B，如果后面的代码还使用到了B，则B所占的内存一直保留，有一种情况例外，在内存极度不足的情况下，IOS会遵从一定的策略有可能把B释放，B再次被使用的时候再重新创建另外，即使pop后后面的代码不再使用B了，那么B的内存只是有可能被释放，释放的时机并不一定，这取决于垃圾回收器的回收策略
    */
    
    
    
    
    
    
    
    /*
     　navigationController自带了一个工具栏，通过设置 self.navigationController.toolbarHidden = NO来显示工具栏，工具栏中的内容可以通过viewController的toolbarItems来设置，显示的顺序和设置的NSArray中存放的顺序一致，其中每一个数据都一个UIBarButtonItem对象，可以使用系统提供的很多常用风格的对象，也可以根据需求进行自定义。
     
     　　设置Toolbar内容的例子：
     */
    
    self.navigationController.toolbarHidden = NO ;
    
    UIBarButtonItem *one = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:nil action:nil];
    UIBarButtonItem *two = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemBookmarks target:nil action:nil];
    UIBarButtonItem *three = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:nil action:nil];
    UIBarButtonItem *four = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemEdit target:nil action:nil];
    UIBarButtonItem *flexItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    [self setToolbarItems:[NSArray arrayWithObjects:flexItem, one, flexItem, two, flexItem, three, flexItem, four, flexItem, nil]];
    
    
}

//UINavigationControllerDelegate
//相当于 viewController要显示的时候通知一下外面，给你一个机会进行设置，包含如下两个函数：

-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    
}



-(void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    
}


-(void)rightAction:(UIBarButtonItem *)itemButton{
    
    SecondViewController *secongVC= [[SecondViewController alloc] init];
    
    //从当前视图push到目标视图，如果视图已经存在，则不影响堆栈
    [self.navigationController pushViewController:secongVC  animated:YES];
    
    
}

-(void)Action:(UIButton *)btn
{
    
}