UIViewController生命周期需要注意的

@property(nonatomic,retain)
UIView *view;
// The getter first invokes [self loadView] if the view hasn't been set yet. Subclasses must call super if they override the setter or getter.

如果没有生成view，那么self.view会先调用[self loadView],然后。。。

(void)viewDidLoad;
// Called after the view has been loaded. For view controllers created in code, this is after -loadView. For view controllers unarchived from a nib, this is after the view is set.

然后调用viewDidLoad，注意this is after -loadView.

总结，self.view->[self loadView]->[self viewDidLoad]。