UIScreen（屏幕）、UIWindow（畫框）、UIView(畫布)、didFinishLaunchingWithOptions的概念

 

//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 *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
     //返回的是帶有狀態欄的矩形
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
   
    CGRect bound = [[UIScreen mainScreen]bounds];   //返回的是帶有狀態欄的Rect
    NSLog(@"boundwith:%f    boundheight:%f",bound.size.width,bound.size.height); 
    NSLog(@"boundx:%f    boundy:%f",bound.origin.x,bound.origin.y); 
    //2012-08-03 23:21:45.716 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 = [[UIScreen mainScreen]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);
    //2012-08-03 23:21:45.720 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
  
    MasterViewController *masterViewController = [[[MasterViewController alloc] initWithNibName:@"MasterViewController" bundle:nil] autorelease]; //根據nib文件的名稱來建立一個視圖控制器

    self.navigationController = [[[UINavigationController alloc] initWithRootViewController:masterViewController] autorelease]; //建立一個導航控制器，並指定該導航控制器的根視圖控制器爲上面創建的masterViewController

    self.window.rootViewController = self.navigationController;//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早顯示的視圖。要讓你的視圖控制器的內容顯示在窗體中，須要去設置窗體的根視圖控制器爲你的視圖控制器。
   
     [self.window makeKeyAndVisible]; //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。
    return YES;
}

轉自:http://blog.sina.com.cn/s/blog_74f70b7901017f9t.html