AppDelegate

• delegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// app 启动就启动
NSLog(@"%s",__func__);
return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application {
// app将要进入后台
}

- (void)applicationDidEnterBackground:(UIApplication *)application {
// app已经进入后台
}

- (void)applicationWillEnterForeground:(UIApplication *)application {
// app将要打开
}

- (void)applicationDidBecomeActive:(UIApplication *)application {
// app处于活跃状态
}

- (void)applicationWillTerminate:(UIApplication *)application {
// app将要被杀死
}

• 特殊--内存警告的时候

- (void)applicationDidReceiveMemoryWarning:(UIApplication *)application{
// app接受到内存警告的时候滴啊用
// 清空图片
}