1、应用程序委托对象

在应用程序委托对象中接收内存警告消息，需要重写applicationDidReceiveMemoryWarning:方法。AppDelegate的代码片段：

- (void)applicationDidReceiveMemoryWarning:(UIApplication *)application

{

NSLog(@”AppDelegate中调用applicationDidReceiveMemoryWarning:”);

}



2、视图控制器

在视图控制器中接收内存警告消息，需要重写didReceiveMemoryWarning方法。ViewController的代码片段：

- (void)didReceiveMemoryWarning

{

NSLog(@”ViewController中didReceiveMemoryWarning调用”);

[super didReceiveMemoryWarning];

//释放成员变量

[_listTeams release];

}



注意释放资源代码应该放在[super didReceiveMemoryWarning]语句下面。

3、其它类

在其它类中可以使用通知，在内存警告时候iOS系统会发出UIApplicationDidReceiveMemoryWarningNotification通知，凡是在通知中心注册了

UIApplicationDidReceiveMemoryWarningNotification通知的类都会接收到内存警告通知。ViewController的代码片段：

- (void)viewDidLoad

{

[super viewDidLoad];

NSBundle *bundle = [NSBundle mainBundle];

NSString *plistPath = [bundle pathForResource:@"team"

ofType:@"plist"];

//获取属性列表文件中的全部数据

NSArray *array = [[NSArray alloc] initWithContentsOfFile:plistPath];

self.listTeams = array;

[array release];

    //接收内存警告通知，调用handleMemoryWarning方法处理

    NSNotificationCenter *center = [NSNotificationCenter defaultCenter];

    [center addObserver:self

               selector:@selector(handleMemoryWarning)

                   name:UIApplicationDidReceiveMemoryWarningNotification

                 object:nil];

}

//处理内存警告

-(void) handleMemoryWarning

{

    NSLog(@”ViewController中handleMemoryWarning调用“);

}


我们在viewDidLoad方法中注册UIApplicationDidReceiveMemoryWarningNotification消息，接收到报警信息调用handleMemoryWarning方法。这些代码完全可以写在其它类中，在ViewController中重写didReceiveMemoryWarning方法就可以了，本例这是示意性介绍一下UIApplicationDidReceiveMemoryWarningNotification报警消息。

内存警告在设备上出现并不是经常的，一般我们没有办法模拟，但模拟器上有一个功能可以模拟内存警告，启动模拟器，选择模拟器菜单硬件→模拟内存警告，这个时候我们会在输出窗口中看到内存警告发生了。

2012-11-06 16:49:16.419 RespondMemoryWarningSample[38236:c07] Received memory warning.

2012-11-06 16:49:16.422 RespondMemoryWarningSample[38236:c07] AppDelegate中调用applicationDidReceiveMemoryWarning:

2012-11-06 16:49:16.422 RespondMemoryWarningSample[38236:c07] ViewController中handleMemoryWarning调用

2012-11-06 16:49:16.423 RespondMemoryWarningSample[38236:c07] ViewController中didReceiveMemoryWarning调用