UI入门 纯代码 第一节 UIWindow, UIView

 //一下为纯代码写的工程,所以先要删掉左侧的 StoryBoard,然后点击左侧最上面那行,就是你的工程刚进来的时候那个页面,删掉 interface Main中的 Main

 1　　  //初始化window,并设置大小
　 　self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    //设置window背景颜色 白色
    self.window.backgroundColor = [UIColor whiteColor];
    
    [self.window makeKeyAndVisible];
    //设置主视图控制器
    ViewController *rootVier = [[ViewController alloc] init];
    self.window.rootViewController = rootVier;
    
    //1.创建UIView对象
    //初始化aView
    UIView *aView = [[UIView alloc] init];
    
    //2.设置AView背景颜色
    aView.backgroundColor = [UIColor blackColor];
    
    //3.设置frame 位置和大小
    aView.frame = CGRectMake(100, 300, 100, 100);
    
    //4.将aView添加到window视图上
    [self.window addSubview:aView];
    
    UIView *aView2 = [[UIView alloc] init];
    aView2.backgroundColor = [UIColor grayColor];
    aView2.frame = CGRectMake(200, 300, 100, 100);
    [self.window addSubview:aView2];
    
    UIView *aView3 = [[UIView alloc] init];
    aView3.backgroundColor = [UIColor yellowColor];
    aView3.frame = CGRectMake(100, 400, 100, 100);
    [self.window addSubview:aView3];
    
    UIView *aView4 = [[UIView alloc] init];
    aView4.backgroundColor = [UIColor redColor];
    aView4.frame = CGRectMake(200, 400, 100, 100);
    [self.window addSubview:aView4];
    
    UIView *cView = [[UIView alloc] init];
    //设置cView的大小和位置
    cView.frame = CGRectMake(CGRectGetMinX(aView4.frame), CGRectGetMaxY(aView4.frame), CGRectGetWidth(aView4.frame), CGRectGetHeight(aView4.frame));
    [self.window addSubview:cView];
    
    UIView *dView = [[UIView alloc] init];
    dView.backgroundColor = [UIColor yellowColor];
    dView.frame = CGRectMake(30, 10, 50, 50);
    [aView addSubview:dView];
    
    UIView *eView = [[UIView alloc] init];
    eView.backgroundColor = [UIColor redColor];
    eView.frame = CGRectMake(25, 25, 50, 50);
    [aView2 addSubview:eView];