UIViewController的生命周期

- (instancetype)init
{
    self = [super init];
    if (self) {
        NSLog(@"%s", __func__);
    }
    return self;
}
- (void)loadView {
    [super loadView];
    NSLog(@"%s", __func__);
}
- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"%s", __func__);
}
- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    NSLog(@"%s", __func__);
}
- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    NSLog(@"%s", __func__);
}
- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    NSLog(@"%s", __func__);
}
- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];
    NSLog(@"%s", __func__);
}
- (void)dealloc
{
    NSLog(@"%s", __func__);
}