UIWindow UIScreen UIViewController UIView之間的關係

轉自：

http://blog.csdn.net/heng615975867/article/details/39053695

UIScreen(屏幕，一直存在)
---》UIWindow(畫框)
---》UIViewController(視圖控制器)
---》UIView(視圖)

//didFinishLaunchingWithOptions 方法：顧名思義。在app開始運行時會調用裏面的方法。

-(BOOL)application:(UIApplication *)applicationdidFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    //返回的是帶有狀態欄的矩形
    self.window = [[[UIWindow alloc]initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

   //返回的是帶有狀態欄的Rect 
  CGRect bound = [[UIScreen mainScreen]bounds]; 
    NSLog(@"boundwith:%f    boundheight:%f",bound.size.width,bound.size.height); 
  NSLog(@"boundx:%f    boundy:%f",bound.origin.x,bound.origin.y); 
    //2012-08-0323:21:45.716 DinkMixer[599:c07]boundwith:320.000000    boundheight:480.000000
    //2012-08-03 23:21:45.719 DinkMixer[599:c07] boundx:0.000000    boundy:0.000000

    CGRect appBound = [[UIScreenmainScreen]applicationFrame];  //返回的是不帶有狀態欄的Rect
    NSLog(@"appBoundwith:%f    boundheight:%f",appBound.size.width,appBound.size.height); 
  NSLog(@"appBoundx:%f    boundy:%f",appBound.origin.x,appBound.origin.y);
    //2012-08-0323:21:45.720 DinkMixer[599:c07]appBoundwith:320.000000    boundheight:460.000000
  //2012-08-03 23:21:45.720 DinkMixer[599:c07]appBoundx:0.000000    boundy:20.000000
    //很明顯狀態欄佔用了空間20像素

    //根據nib文件的名稱來創建一個視圖控制器
    MasterViewController*masterViewController = [[[MasterViewController alloc]initWithNibName:@"MasterViewController" bundle:nil] autorelease];

   //創建一個導航控制器，並指定該導航控制器的根視圖控制器爲上面建立的masterViewController
    self.navigationController= [[[UINavigationController alloc]initWithRootViewController:masterViewController] autorelease];
  //窗體（window）有一個根視圖控制器——這個視圖控制器負責配置當窗體顯示時最先顯示的視圖。要讓你的視圖控制器的內容顯示在窗體中，需要去設置窗體的根視圖控制器爲你的視圖控制器。
    self.window.rootViewController = self.navigationController;
   

    //這行代碼會讓包含了視圖控制器視圖的Window窗口顯示在屏幕上。
    [self.window makeKeyAndVisible];
    return YES;
}

---》UIView(視圖)(視圖)