ios - 如何使视图功能在滚动视图中工作

Question

请看下面的代码

-(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bViewController现在访问，我想在离开时显示警报bViewController，但viewDidUnload不起作用。

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

那么哪个可以工作？

Answer 1

我可以建议scrollViewDidScroll:在scrollView.contentOffset.x < 1024.0f.