UINavigationController与UITabBarController是iOS开发中最常用的两种视图控制器,它们都属于UIViewController的子类,继承关系如下:
@interface UITabBarController : UIViewController
@interface UINavigationController : UIViewController
UINavigationController:同级页面之间的跳转,界面典型的特点就是页面上部有一UINavigationBar导航条,导航条可以设置标题、左上角的按钮(一般用于返回),右上角的按钮,也可以自定义这些元素。
UITabBarController:父子页面之间的嵌套关系,界面典型的特点是耍耍下部有一UITabBar选项组,通过点击Tab,可切换上面的视图的变换。
UIViewController、UINavigationController、UITabBarController三者的整合使用,可以开发出大部分的App应用页面框架。
一、在我们项目AppDelegate中添加UIViewController
//把UIViewController添加的应用中:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
SplashViewController *splashViewController = [[SplashViewController alloc] initWithNibName:@"SplashViewController" bundle:nil];
self.window.rootViewController = splashViewController;
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
二、UIViewController之间的跳转与传参
一般的应用程序都不会只有一个页面,而页面之间的跳转,可以这样调用:
//从UIViewController跳转到另一个UIViewController
LoginViewController *loginViewController = [[LoginViewController alloc] initWithNibName:@"LoginViewController" bundle:nil];
[self presentViewController:loginViewController animated:true completion:^{}];
//从UIViewController返回上一个UIViewController
[self dismissViewControllerAnimated:true completion:^{}];
很多从Android开发转过来的同事,都会问一个问题:两个页面之间怎么传递参数?
其实,Android通过Intent对象来跳转和传递参数,当前页面是拿不到下一个页面的实例;而在iOS中,我们是通过直接创建的方式创建下一个页面实例的,所以,你可以在下一个UIViewController实例中提供一个方法,供当前页面去给它设置参数就行。
在Android中,返回上一个页面,还是通过Intent来回传参数;而在iOS中,可通过设置代理的方式来传参。具体使用下面的例子中会看到。
三、由UIViewController跳转到UITabBarController
//从UIViewController跳转到UINavigationController
HomeViewController *homeViewController = [[HomeViewController alloc] initWithNibName:@"HomeViewController" bundle:nil];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:homeViewController];
[self presentViewController:navigationController animated:true completion:^{}];
//HomeViewController是一个UITabBarController子类
@interface HomeViewController : UITabBarController
@end
在本例中,这个UITabBarController还属于UINavigationController导航链中的一个环节,故可以调用导航控制器相应的方法。
UITabBarController本身可以嵌套多个子页面的,每个页面可以由一个UIViewController来提供。代码如下:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
//设置导航标题
self.title = @"Message";
//设置导航左上角的按钮
UIBarButtonItem *leftBtn = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStylePlain target:self action:@selector(onLeftBtnClick:)];
self.navigationItem.leftBarButtonItem = leftBtn;
//设置导航右上角的按钮
UIImage *img = [UIImage imageNamed:@"msgIcon"];
UIBarButtonItem *rightBtn = [[UIBarButtonItem alloc] initWithImage:img style:UIBarButtonItemStyleBordered target:self action:nil];
self.navigationItem.rightBarButtonItem = rightBtn;
//新建Tab页面
UserListViewController *userListViewController = [[UserListViewController alloc] initWithNibName:@"UserListViewController" bundle:nil];
MessageListViewController *messageListViewController = [[MessageListViewController alloc] initWithNibName:@"MessageListViewController" bundle:nil];
//添加Tab耍耍到Tab控制器
self.viewControllers = @[messageListViewController, userListViewController];
//设置UITabBarControllerDelegate代理
self.delegate = self;
}
return self;
}
HomeViewController实现了UITabBarControllerDelegate协议,可用于Tab切换时执行某此操作,如下:
//实现协议方法,用于切换Tab时,更改页面的标题
-(void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
NSInteger index = tabBarController.selectedIndex;
NSString *title;
switch (index) {
case 0:
title = @"Message";
break;
case 1:
title = @"User List";
break;
}
self.title = title;
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
self.tabBarItem.title = @"User List";
self.tabBarItem.image = [UIImage imageNamed:@"chatIcon01"];
}
return self;
}
从UITabBarController子页面跳转到UINavigationController的下一个页面,注意:前提是UITabBarController是属于UINavigationController导航链中的一个节点。
//从UITabBarController的子页面跳转到UINavigationController的下一个页面:
ChatViewController *chatViewController = [[ChatViewController alloc] initWithNibName:@"ChatViewController" bundle:nil];
UITabBarController *homeController = self.tabBarController;
[chatViewController setHomeDelegate:homeController];
[self.tabBarController.navigationController pushViewController:chatViewController animated:true];
@protocol HomeDelegate
-(void) onComeback:(NSString*) message;
@end
@interface ChatViewController : UIViewController
@property (weak) id homeDelegate;
@end
@implementation ChatViewController
@synthesize homeDelegate;
@end
要从ChatViewController返回到上一个页面,可执行下面代码:
[homeDelegate onComeback:@"Hello"];
[self.navigationController popViewControllerAnimated:true];
UINavigationController的页面回退的两个常用方法:
//返回导航的上一个页面
[self.navigationController popViewControllerAnimated:true];
//返回导航的第一个页面
[self.navigationController popToRootViewControllerAnimated:true];
@容新华技术博客 - http://blog.csdn.net/rongxinhua - 原创文章,转载请注明出处