iOS - Training (9) - UINavigationController

方便切換UIViewController。為一個stack型態的容器，使用者視角從stack的入口看下去，所以後來放入的view會蓋過舊的view而被使用者看到，相對的回上一個view時，上層的view會被取消掉而不存在：

使用範例：

新增一個繼承UIViewController的類別Controller_A，連同Xib一起產生；同樣的也新增一個Controller_B。在A的Xib中拉入button，定義button的action

#import "Controller_B.h" - (IBAction)callController:(id)sender {     Controller_B* conB = [[Controller_B alloc] initWithNibName:@"Controller_B" bundle:nil];          [self.navigationController pushViewController:conB animated:YES]; // UIViewController中有navigationController這個property，用來將Controller放入UINavigationController的stack中 //    [conB release]; // If no ARC }

先在Delega.h中加入UINavigationController

@interface AppDelegate : UIResponder <UIApplicationDelegate> {     UINavigationController* navController; }

再定義Delega.m

#import "Controller_A.h" - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {     // Override point for customization after application launch.     Controller_A* conA = [[Controller_A alloc] initWithNibName:@"Controller_A" bundle:nil];     navController = [[UINavigationController alloc] initWithRootViewController:conA]; //初始化時將conA物件放入navController     self.window.rootViewController = navController; //將navController放入主畫面中     [self.window makeKeyAndVisible];          return YES; }

自訂UINavigationBar樣式 -----
在採用UINavigateController時，畫面上方會出現條bar，可以自行定義bar裡的內容，分別有leftBarButtonItem、titleView、rightBarButtonItem

titleView：
在UIViewController之中提供navigationItem.title property來設定title

- (void)viewDidLoad {     [super viewDidLoad];     // Do any additional setup after loading the view from its nib.     self.navigationItem.title = @"Controller A"; }

leftBarButtonItem或rightBarButtonItem：
使用UIBarButtonItem，並將navigationItem.rightBarButtonItem指向UIBarButtonItem

- (void)viewDidLoad {     [super viewDidLoad];     // Do any additional setup after loading the view from its nib.     self.navigationItem.title = @"Controller A";          UIBarButtonItem* rightBtn = [[UIBarButtonItem alloc] initWithTitle:@"About" style:UIBarButtonItemStylePlain target:self action:@selector(about:)]; //style參數決定按鈕的樣式，target與action設定呼叫的方法          self.navigationItem.rightBarButtonItem = rightBtn; //將rightBtn指向navigationItem.rightBarButtonItem property } -(void) about:(id) sender {     NSLog(@"Hello I am Controller A"); }

改變back button：
同樣使用UIBarButtonItem來改變原有的back button

- (void)viewDidLoad {     [super viewDidLoad];     // Do any additional setup after loading the view from its nib.     self.navigationItem.title = @"Controller A";          UIBarButtonItem* rightBtn = [[UIBarButtonItem alloc] initWithTitle:@"About" style:UIBarButtonItemStylePlain target:self action:@selector(about:)]; //style參數決定按鈕的樣式，target與action設定呼叫的方法          self.navigationItem.rightBarButtonItem = rightBtn; //將rightBtn指向navigationItem.rightBarButtonItem property     UIBarButtonItem* backBtn = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:nil action:nil]; //style和target為UINavigationController控制，故就算給予定義也不會有反應          self.navigationItem.backBarButtonItem = backBtn; } -(void) about:(id) sender {     NSLog(@"Hello I am Controller A"); }

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資料出處《Object-C與iOS開發入門》