如何使功能於一身的滾動視圖工作視圖

Question

請看看下面的代碼

-(void)viewDidLoad{ 
    self.viewControllers = [NSMutableArray arrayWithCapacity:0]; 
    UIViewController* controller = nil; 

    controller = [[aViewController alloc]initWithNibName:@"aViewController" bundle:nil]; 
    controller.view.frame = CGRectMake(1024*0, 0, 1024, 768); 
    [scrollView1 addSubview:controller.view]; 
    [viewControllers addObject:controller]; 

    controller = [[bViewController alloc]initWithNibName:@"bViewController" bundle:nil]; 
    controller.view.frame = CGRectMake(1024*1, 0, 1024, 768); 
    [scrollView1 addSubview:controller.view]; 
    [viewControllers addObject:controller]; 

    controller = [[cViewController alloc]initWithNibName:@"cViewController" bundle:nil]; 
    controller.view.frame = CGRectMake(1024*2, 0, 1024, 768); 
    [scrollView1 addSubview:controller.view]; 
    [viewControllers addObject:controller]; 

} 

我參觀bViewController現在，我希望當我離開bViewController顯示一個警告，但viewDidUnload不起作用。

- (void)viewWillDisappear:(BOOL)animated也不起作用。

那麼哪個可以工作？

Answer 1

當scrollView.contentOffset.x < 1024.0f時，我可以建議顯示scrollViewDidScroll:方法的警報。