详谈UINavigationController

UINavigationController是IOS编程中比较常用的一种容器view controller，很多系统的控件(如UIImagePickerViewController)以及很多有名的APP中(如qq，系统相册等)都有用到。

1.创建第一个视图控制器

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    _window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

    

    //创建第一个视图控制器，并用其创建导航控制器

    FirstViewController *fvc = [[FirstViewController alloc] init];

    UINavigationController *nc = [[UINavigationController alloc] initWithRootViewController:fvc];

    //将导航控制器作为window的根视图控制器

    self.window.rootViewController = nc;

    [fvc release];

    [nc release];

    

    self.window.backgroundColor = [UIColor whiteColor];

    [self.window makeKeyAndVisible];

    return YES;

}

2.设置标题及颜色

- (void)viewDidLoad {

    [super viewDidLoad];

    //设置标题，若不设置下个视图左边默认显示back

    //若显示不完，在下个视图左边仍会显示默认back

    self.title = @"firstViewController";

    self.view.backgroundColor = [UIColor redColor];

    [self createButtons];

}

3.在第一个视图上创建button  用于点击进入下一个视图

- (void)createButtons

{

    NSArray *titles = @[@"next"];

    for (NSUInteger i=0; i<titles.count; i++) {

        UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];

        button.frame = CGRectMake(0, 0, 200, 50);

        button.center = CGPointMake(self.view.frame.size.width/2, 100+80*i);

        button.backgroundColor = [UIColor whiteColor];

        [button setTitle:titles[i] forState:UIControlStateNormal];

        button.titleLabel.font = [UIFont systemFontOfSize:30];

        [button addTarget:self action:@selector(clickHandle:) forControlEvents:UIControlEventTouchUpInside];

        button.tag = 100+i;

        [self.view addSubview:button];

    }

}

4.实现button的方法

- (void)clickHandle:(UIButton *)button

{

    switch (button.tag) {

        case 100:

        {

            //创建第二个视图控制器

            SecondViewController *svc = [[SecondViewController alloc] init];

            //将其压到导航控制器中

            [self.navigationController pushViewController:svc animated:YES];

            [svc release];

        }

            break;

            

        default:

            break;

    }

}

5.创建一个

UINavigationItem

- (void)customNavigationItem

{

    //找到NavigationItem

    UINavigationItem *item =  self.navigationItem;

    //设置标题，与上面self.title = @"second";等价

    //最后设置的有效，会覆盖前面的设置

    item.title = @"第二个";

    //设置标题视图（任意的View）

    UIView *view = [[UIView alloc] init];

    view.frame = CGRectMake(0, 0, 44, 44);

    view.backgroundColor = [UIColor grayColor];

    item.titleView = view;

    [view release];

    //创建UIBarButtonItem

    //系统默认风格

    UIBarButtonItem *barItem1 = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemBookmarks target:self action:@selector(barButtonHandle:)];

    barItem1.tag = 100;

    //通过指定图片创建item

    UIImage *image = [UIImage imageNamed:@"itemImage"];

    //设置图片渲染效果

    image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

    UIBarButtonItem *barItem2 = [[UIBarButtonItem alloc] initWithImage:image style:UIBarButtonItemStylePlain target:self action:@selector(barButtonHandle:)];

    barItem2.tag = 200;

    //通过指定标题创建item

    UIBarButtonItem *barItem3 = [[UIBarButtonItem alloc] initWithTitle:@"title" style:UIBarButtonItemStyleDone target:self action:@selector(barButtonHandle:)];

    barItem3.tag = 300;

    //自定义view创建item

    UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];

    button.frame = CGRectMake(0, 0, 44, 44);

    button.titleLabel.adjustsFontSizeToFitWidth = YES;

    [button setTitle:@"custom" forState:UIControlStateNormal];

    [button addTarget:self action:@selector(barButtonHandle:) forControlEvents:UIControlEventTouchUpInside];

    button.tag = 400;

    UIBarButtonItem *barItem4 = [[UIBarButtonItem alloc] initWithCustomView:button];

    

    //不建议使用

    //item.backBarButtonItem = barItem2;

    

    //设置单个

    //item.leftBarButtonItem = barItem1;

    //设置多个

    item.leftBarButtonItems = @[barItem1,barItem2,barItem3,barItem4];

    [barItem1 release];

    [barItem2 release];

    [barItem3 release];

    [barItem4 release];

    

    //右边设置方式与左边一样，但是item的顺序是与数组相反的

}