初识UI

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

    UIWindow * window = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];

    self.window = window;

    window.backgroundColor = [UIColor grayColor];

    [self.window makeKeyAndVisible];

    CGRect rect = self.window.frame;

    NSLog(@"%@",NSStringFromCGRect(rect));// 获取当前window尺寸

    

    // 1. 创建一个视图并且显示到window

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

    view.frame = CGRectMake(200, 100, 100, 190);// 控制当前视图的位置宽高

    view.backgroundColor = [UIColor greenColor];// 设置子控件的颜色

    

    [self.window addSubview:view];// 添加子控件到父视图

    // 子视图frame

    NSLog(@"%@",NSStringFromCGRect(view.frame));

    // 子视图bounds

    NSLog(@"%@",NSStringFromCGRect(view.bounds));

    // 子视图中心

    NSLog(@"%@",NSStringFromCGPoint(view.center));

    

// 创建myView

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

    CGRect  myRect = CGRectMake(120, 220, 30, 40);

    myView.frame = myRect;

    myView.backgroundColor = [UIColor brownColor];

    [self.window addSubview:myView];

// 创建mySecondView    

    UIView * mySecondView = [[UIView alloc]initWithFrame:CGRectMake(100, 200, 290, 40)];

    mySecondView.backgroundColor = [UIColor purpleColor];

    [self.window addSubview:mySecondView];

    UIView，window，UIColor，CGRect，CGPoint，oc    

// 创建myThirdView

    // 视图插入到当前的索引位置

    UIView * myThirdView = [[UIView alloc]initWithFrame:CGRectMake(150, 170, 90, 40)];

    myThirdView.backgroundColor = [UIColor cyanColor];

    UIView，window，UIColor，CGRect，CGPoint，oc    

    [self.window insertSubview:myThirdView atIndex:2];// 将视图插入到下标的位置

    [self.window insertSubview:myView aboveSubview:myThirdView];// 将视图myView移到myThirdView之上

    [self.window bringSubviewToFront:view];// 将视图view移到最上面

UIView，window，UIColor，CGRect，CGPoint，oc    

    [self.window sendSubviewToBack:myView];// 将视图view移到最下面

    UIView，window，UIColor，CGRect，CGPoint，oc    

    [self.window exchangeSubviewAtIndex:2 withSubviewAtIndex:0];// 将两位视图的下标交换，来交换两个视图的位置

    [view removeFromSuperview]; // 将子视图从父视图中删除掉

    UIView，window，UIColor，CGRect，CGPoint，oc    

UIView，window，UIColor，CGRect，CGPoint，oc    

    return YES;

}