IOS AppDelegate.m 詳解

今天在學習 IOS 中 Storyboard 的使用中，操作都是沒問題的，就是啟動后一直出現的是 白色 界面，不能進行跳轉操作。找了好久也沒找到方法，最后，問了老大，發現了問題所在，原來是 AppDelegate.m 文件中的， 該注釋掉的沒注釋掉 ：

 

 
- (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];
    //[self.window makeKeyAndVisible];
    return YES;
}

 

因為之前一直對 IOS 中的  AppDelegate.m 不太了解，才會導致這個問題，所以這次一定要徹底的搞明白  AppDelegate.m  這個重要的文件，這將極大的幫助你了解 Xcode 中 IOS 的開發~

 

關於 AppDelegate，有一個國外的用戶，總結的特別好：

 

AppDelegate.h/m define a class that manages the application overall. The app will create one instance of that class and send that object messages that let the delegate influence the app's behavior at well-defined times. For example, -application:didFinishLaunchingWithOptions: is sent when the app has finished launching and is ready to do something interesting. Take a look at the   UIApplicationDelegate reference page  for a list of messages that the app delegate can implement to modify the behavior of the application.

 

看到了吧，如果通過上面的解釋，可以看出來，AppDelegate.h/m 是一個很重要的文件，如果你做過 Asp.Net 開發，那么這個文件就類似於 .Net 中的 Global.ascx 文件，就是做一些全局變量的控制的。

 

本文禁止任何網站轉載，嚴厲譴責那些蛀蟲們。
本文首發於，博客園，請搜索：博客園 - 尋自己，查看原版文章
本文首發地址：IOS AppDelegate.m 詳解 - www.cnblogs.com/xunziji/archive/2012/09/17/2689184.html

 

下面就過一下，AppDelegate.h/m 中默認的方法：

 

 

1. application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

 

Tells the delegate when the application has launched and may have additional launch options to handle.

 

在應用程序啟動后，要執行的委托調用。

 

 

 

2. applicationWillResignActive:(UIApplication *)application

 

Tells the delegate that the application is about to become inactive.This method is called to let your application know that it is about to move from the active to inactive state.After calling this method, the application also posts a UIApplicationWillResignActiveNotification notification to give interested objects a chance to respond to the transition.

 

在應用程序將要由活動狀態切換到非活動狀態時候，要執行的委托調用，如 按下 home 按鈕，返回主屏幕，或全屏之間切換應用程序等。

 

 

本文禁止任何網站轉載，嚴厲譴責那些蛀蟲們。
本文首發於，博客園，請搜索：博客園 - 尋自己，查看原版文章
本文首發地址：IOS AppDelegate.m 詳解 - www.cnblogs.com/xunziji/archive/2012/09/17/2689184.html

 

3. applicationDidEnterBackground:(UIApplication *)application

 

Tells the delegate that the application is now in the background.Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.

 

在應用程序已進入后台程序時，要執行的委托調用。

 

 

 

4. applicationWillEnterForeground:(UIApplication *)application

 

Tells the delegate that the application is about to enter the foreground.Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.

 

在應用程序將要進入前台時(被激活)，要執行的委托調用，剛好與 applicationWillResignActive 方法相對應。

 

 

 

5. applicationDidBecomeActive:(UIApplication *)application

 

Tells the delegate that the application has become active.Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.

 

在應用程序已被激活后，要執行的委托調用，剛好與   applicationDidEnterBackground 方法相對應。

 

 

6. applicationWillTerminate:(UIApplication *)application

 

Tells the delegate when the application is about to terminate.Called when the application is about to terminate. Save data if appropriate.

 

本文禁止任何網站轉載，嚴厲譴責那些蛀蟲們。
本文首發於，博客園，請搜索：博客園 - 尋自己，查看原版文章
本文首發地址：IOS AppDelegate.m 詳解 - www.cnblogs.com/xunziji/archive/2012/09/17/2689184.html

在應用程序要完全推出的時候，要執行的委托調用。

 

 

有沒有發現，IOS 中的 AppDelegate.m/h 文件是很重要的呢，因為它是對 Application 的整個生命周期進行管理的，有木有~

 

本文禁止任何網站轉載，嚴厲譴責那些蛀蟲們。
本文首發於，博客園，請搜索：博客園 - 尋自己，查看原版文章
本文首發地址：IOS AppDelegate.m 詳解 - www.cnblogs.com/xunziji/archive/2012/09/17/2689184.html