//AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    // Override point for customization after application launch.    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];        self.window.backgroundColor=[UIColor whiteColor];        RootViewController *rootView=[[RootViewController alloc]init];        UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:rootView];        [_window setRootViewController:nav];        [nav release];    [rootView release];            return YES;}

//RootViewController.m- (void)viewDidLoad {    // Do any additional setup after loading the view.    [super viewDidLoad];    // Do any additional setup after loading the view.    [self.navigationController.navigationBar setTranslucent:NO];//設置navigationbar的半透明        self.title = @"RootViewController";//設置navigationbar上顯示的標題        [self.navigationController.navigationBar setBarTintColor:[UIColor purpleColor]];//設置navigationbar的顏色        self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonItemStyleDone target:self action:Nil];//設置navigationbar左邊按鈕        self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonItemStylePlain target:self action:Nil];//設置navigationbar右邊按鈕        [self.navigationController.navigationBar setTintColor:[UIColor whiteColor]];//設置navigationbar上左右按鈕字體顏色         //self.navigationItem.rightBarButtonItem setTarget:<#(id)#>    //動態添加一個按鈕         UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];        button.frame = CGRectMake(0, 300, 300, 50);        [button setTitle:@"新添加的動態按鈕" forState: UIControlStateNormal];        button.backgroundColor = [UIColor clearColor];        button.tag = 2000;        [button addTarget:self action:@selector(clicked:) forControlEvents:UIControlEventTouchUpInside];        [self.view addSubview:button];    }- (void)clicked:(id) sender{    SecondViewController *second = [[SecondViewController alloc]init];    [self.navigationController pushViewController:second animated:YES];    //second.str = @"hello!!";    [second release];}//這個是新按鈕的響應函數-(IBAction) buttonClicked:(id)sender {    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示"                                                    message:@"單擊了動態按鈕！"                                                   delegate:self                                          cancelButtonTitle:@"確定"                                          otherButtonTitles:nil];    [alert show];    [alert release];}