UIViewController的生命周期

//只调用一次

- (void)viewDidLoad {

    [super
viewDidLoad];

    

    [self.view
setBackgroundColor:[UIColor
whiteColor]];

    

    NSLog(@"view完成加载后 viewDidLoad");

}

#pragma mark - 以下在界面切换回后都会调用

-(void)viewWillAppear:(BOOL)animated

{

    [super viewWillAppear:animated];

    

    NSLog(@"view将要显示 viewWillAppear");

}

-(void)viewDidAppear:(BOOL)animated

{

    [super viewDidAppear:animated];

    

    NSLog(@"view显示完成 viewDidAppear");

}

-(void)viewWillDisappear:(BOOL)animated

{

    [super viewWillDisappear:animated];

    

    NSLog(@"view将要消失 viewWillDisappear");

}

-(void)viewDidDisappear:(BOOL)animated

{

    [super viewDidDisappear:animated];

    

    NSLog(@"view消失后 viewDidDisappear");

}

- (void)didReceiveMemoryWarning {

    [super
didReceiveMemoryWarning];

    

    NSLog(@"内存警告");

}

界面切换时的操作

2015-12-13 09:56:54.254 Test[760:14450] view完成加载后 viewDidLoad

2015-12-13 09:56:54.255 Test[760:14450] view将要显示 viewWillAppear

2015-12-13 09:56:54.263 Test[760:14450] view显示完成 viewDidAppear

2015-12-13 09:57:00.110 Test[760:14450] view将要消失 viewWillDisappear

2015-12-13 09:57:00.824 Test[760:14450] view消失后 viewDidDisappear

2015-12-13 09:57:06.957 Test[760:14450] view将要显示 viewWillAppear

2015-12-13 09:57:07.460 Test[760:14450] view显示完成 viewDidAppear