app系统程序调用过程

/**
 *  app加载完毕的时候调用(一般只调用一次)
 *
 */
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    NSLog(@"didFinishLaunchingWithOptions");
    return YES;
}

/**
 *  app失去焦点的时候调用(UI控件不能正常使用)
 */
- (void)applicationWillResignActive:(UIApplication *)application
{
    NSLog(@"applicationWillResignActive");
}

/**
 *  app进入后台的时候调用(app消失不见)
 */
- (void)applicationDidEnterBackground:(UIApplication *)application
{
    NSLog(@"applicationDidEnterBackground");
}

/**
 *  app进入前台的时候调用(app显示出来)
 */
- (void)applicationWillEnterForeground:(UIApplication *)application
{
    NSLog(@"applicationWillEnterForeground");
}

/**
 *  当app获得焦点的时候调用(这时候整个app的UI控件都能正常使用)
 */
- (void)applicationDidBecomeActive:(UIApplication *)application
{

    NSLog(@"applicationDidBecomeActive");
}

//app进入后台:休眠,  不能接受事情(比如关闭)
/**
 *  app关闭的时候调用(一般情况下不会调用)
 */
- (void)applicationWillTerminate:(UIApplication *)application
{
    NSLog(@"applicationWillTerminate");
}