IOS 视图生命周期

// 视图加载时调用，还未可见
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(@”视图加载时调用，还未可见”);
}

// 视图可见前调用
- (void)viewWillAppear:(BOOL)animated{
NSLog(@”视图可见前调用”);
}

// 视图可见后调用
- (void)viewDidAppear:(BOOL)animated{
NSLog(@”视图可见后调用”);
}

// 视图不可见前调用
- (void)viewWillDisappear:(BOOL)animated{
NSLog(@”视图不可见前调用”);
}

// 视图不可见后调用
- (void)viewDidDisappear:(BOOL)animated{
NSLog(@”视图不可见后调用”);
}

// 系统低内存时调用
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
NSLog(@”系统低内存时调用”);
}