UIViewController的创建、加载和卸载

一. UIViewController的创建和初始化         1. 通过NIB文件初始化         [ [UIViewController alloc] initWithNibName:nibName bundle:nibBundle];

        - (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle;         2. 通过UIStoryboard初始化               - (id)instantiateViewControllerWithIdentifier:(NSString *)identifier;         3. 重载loadView方法          self.view = [ [UIView alloc] initWithFrame: aRect]; 二.  加载视图  loadView->viewDidLoad->viewWillAppear->viewWillLayoutSubviews->viewDidLayoutSubviews->viewDidAppear        - (void)loadView;                    注：NIB文件中若关联了view，则不用重载该方法        - (void)viewDidLoad;        - (void)viewWillAppear:(BOOL) animated;        - (void)viewWillLayoutSubviews;        - (void)viewDidLayoutSubviews;        - (void)viewDidAppear:(BOOL) animated; 三. 卸载视图 viewWillDisappear->viewDidDisappear->dealloc

      - (void)viewWillDisappear:(BOOL)animated;

      - (void)viewDidDisappear:(BOOL)animated;

      - (void)dealloc;