【程序启动四大对象】UIApplicationDelegate & 程序启动过程

 1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
 2     NSLog(@"app启动完毕的时候调用");
 3     return YES;
 4 }
 5 
 6 - (void)applicationDidReceiveMemoryWarning:(UIApplication *)application {
 7     NSLog(@"app接收到内存警告时调用");
 8 }
 9 
10 - (void)applicationDidEnterBackground:(UIApplication *)application {
11     NSLog(@"app进入后台的时候调用");
12 }
13 
14 - (void)applicationWillResignActive:(UIApplication *)application {
15     NSLog(@"app将要被挂起");
16 }
17 
18 - (void)applicationWillEnterForeground:(UIApplication *)application {
19     NSLog(@"app回到前台");
20 }
21 
22 - (void)applicationDidBecomeActive:(UIApplication *)application {
23     NSLog(@"app激活后");
24 }
25 
26 - (void)applicationWillTerminate:(UIApplication *)application {
27     NSLog(@"app将要关闭");
28 }
29  

1 int main(int argc, char * argv[]) {
2     @autoreleasepool {
3         return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
4     }
5 }