@interface AppDelegate() @property UILabel* show; @end @implementation AppDelegate - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; // Override point for customization after application launch. self.window.backgroundColor = [UIColor whiteColor]; //创建一个UIViewController 对象 UIViewController* controller = [[UIViewController alloc] init]; //让该程序的窗口加载并显示 viewController 视图控制器关联的用户界面 self.window.rootViewController = controller; //创建一个UIView 对象 UIView* rootView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; //设置 controller 显示 rootView 控件 controller.view = rootView; //创建一个圆角按钮 UIButton* button = [UIButton buttonWithType:UIButtonTypeRoundedRect]; //设置按钮的大小 button.frame = CGRectMake(120, 100, 80, 40); //为按钮设置文本 [button setTitle:@"确定" forState:UIControlStateNormal]; //将按钮添加到 rootView 控件中 [rootView addSubview:button]; //创建一个 UILabel 对象 self.show = [[UILabel alloc] initWithFrame:CGRectMake(60, 40, 180, 30)]; // UILabel* show = [[UILabel alloc] initWithFrame:CGRectMake(60, 40, 180, 30)]; //将UILabel 添加到 rootView 控件中 [rootView addSubview: self.show]; //设置 UILabel 默认显示的文本 self.show.text = @"初始文本"; self.show.backgroundColor = [UIColor grayColor]; //为圆角按钮的触碰事件绑定事件处理方法 [button addTarget:self action:@selector(clickHandler:) forControlEvents:UIControlEventTouchUpInside]; //将该 UIWindow 对象设为主窗口并显示出来 [self.window makeKeyAndVisible]; return YES; }
- (void)clickHandler:(id)sender { self.show.text = @"开始学习 IOS 吧!"; }