ios知识点杂记

// 在AppDelete实现该方法
- (void)applicationDidEnterBackground:(UIApplication *)application
{ 
   //进入后台
}
// 在AppDelete实现该方法
- (void)applicationDidBecomeActive:(UIApplication *)application{
    // app启动或者app从后台进入前台都会调用这个方法
}
- (void)applicationWillEnterForeground:(UIApplication *)application {
  // app从后台进入前台都会调用这个方法
}

利用通知在控制器里监听app进入前台或者后台
// app启动或者app从后台进入前台都会调用这个方法
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationBecomeActive) name:UIApplicationDidBecomeActiveNotification object:nil];
// app从后台进入前台都会调用这个方法
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationBecomeActive) name:UIApplicationWillEnterForegroundNotification object:nil];
// 添加检测app进入后台的观察者
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationEnterBackground) name: UIApplicationDidEnterBackgroundNotification object:nil];