頁面滾動查看幫助，不同的視圖控制器每頁？

Question

好的，所以我正在嘗試一個pagescrollView，每個視圖控制器有兩個視圖，所以我可以在每個不同的視圖上工作。我得到了蘋果的示例代碼，看起來他們創建了很多不同的視圖，「他們說，懶惰地說」如何更改代碼，以便我可以將第一頁作爲一個視圖控制器，將第二頁作爲另一個視圖控制器？

- (void)applicationDidFinishLaunching:(UIApplication *)application { 
    // view controllers are created lazily 
    // in the meantime, load the array with placeholders which will be replaced on demand 
    NSMutableArray *controllers = [[NSMutableArray alloc] init]; 
    for (unsigned i = 0; i < kNumberOfPages; i++) { 
     [controllers addObject:[NSNull null]]; 
    } 
    self.viewControllers = controllers; 
    [controllers release]; 

    // a page is the width of the scroll view 
    scrollView.pagingEnabled = YES; 
    scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * kNumberOfPages, scrollView.frame.size.height); 
    scrollView.showsHorizontalScrollIndicator = NO; 
    scrollView.showsVerticalScrollIndicator = NO; 
    scrollView.scrollsToTop = NO; 
    scrollView.delegate = self; 

    pageControl.numberOfPages = kNumberOfPages; 
    pageControl.currentPage = 0; 

    // pages are created on demand 
    // load the visible page 
    // load the page on either side to avoid flashes when the user starts scrolling 
    [self loadScrollViewWithPage:0]; 
    [self loadScrollViewWithPage:1]; 
} 

- (void)loadScrollViewWithPage:(int)page { 
    if (page < 0) return; 
    if (page >= kNumberOfPages) return; 

    // replace the placeholder if necessary 
    MyViewController *controller = [viewControllers objectAtIndex:page]; 
    if ((NSNull *)controller == [NSNull null]) { 
     controller = [[MyViewController alloc] initWithPageNumber:page]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 
    } 

    // add the controller's view to the scroll view 
    if (nil == controller.view.superview) { 
     CGRect frame = scrollView.frame; 
     frame.origin.x = frame.size.width * page; 
     frame.origin.y = 0; 
     controller.view.frame = frame; 
     [scrollView addSubview:controller.view]; 
    } 
} 

- (void)scrollViewDidScroll:(UIScrollView *)sender { 
    // We don't want a "feedback loop" between the UIPageControl and the scroll delegate in 
    // which a scroll event generated from the user hitting the page control triggers updates from 
    // the delegate method. We use a boolean to disable the delegate logic when the page control is used. 
    if (pageControlUsed) { 
     // do nothing - the scroll was initiated from the page control, not the user dragging 
     return; 
    } 
    // Switch the indicator when more than 50% of the previous/next page is visible 
    CGFloat pageWidth = scrollView.frame.size.width; 
    int page = floor((scrollView.contentOffset.x - pageWidth/2)/pageWidth) + 1; 
    pageControl.currentPage = page; 

    // load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling) 
    [self loadScrollViewWithPage:page - 1]; 
    [self loadScrollViewWithPage:page]; 
    [self loadScrollViewWithPage:page + 1]; 

    // A possible optimization would be to unload the views+controllers which are no longer visible 
} 

// At the end of scroll animation, reset the boolean used when scrolls originate from the UIPageControl 
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { 
    pageControlUsed = NO; 
} 

- (IBAction)changePage:(id)sender { 
    int page = pageControl.currentPage; 
    // load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling) 
    [self loadScrollViewWithPage:page - 1]; 
    [self loadScrollViewWithPage:page]; 
    [self loadScrollViewWithPage:page + 1]; 
    // update the scroll view to the appropriate page 
    CGRect frame = scrollView.frame; 
    frame.origin.x = frame.size.width * page; 
    frame.origin.y = 0; 
    [scrollView scrollRectToVisible:frame animated:YES]; 
    // Set the boolean used when scrolls originate from the UIPageControl. See scrollViewDidScroll: above. 
    pageControlUsed = YES; 
} 

謝謝如果有人知道如何做到這一點。

Answer 1

要加載不同的視圖控制器的網頁，所有您需要改變的是這個代碼段

MyViewController *controller = [viewControllers objectAtIndex:page]; 
if ((NSNull *)controller == [NSNull null]) 
{ controller = [[MyViewController alloc] initWithPageNumber:page]; 
[viewControllers replaceObjectAtIndex:page withObject:controller]; 
[controller release]; 
} 

初始化每個視圖控制器，你要同一個每次而不是一個，因此代碼看起來像

if(page==0) 
{ 
MyViewControllerZero *controller = [viewControllers objectAtIndex:page]; 
    if ((NSNull *)controller == [NSNull null]) 
    { controller = [[MyViewControllerZero alloc] initWithPageNumber:page]; 
    [viewControllers replaceObjectAtIndex:page withObject:controller]; 
    [controller release]; 
    } 
} 
    if(page==1) 
{ 
MyViewControllerOne *controller = [viewControllers objectAtIndex:page]; 
    if ((NSNull *)controller == [NSNull null]) 
    { controller = [[MyViewControllerOne alloc] initWithPageNumber:page]; 
    [viewControllers replaceObjectAtIndex:page withObject:controller]; 
    [controller release]; 
    } 
} 
//and so on ... 

Answer 2

這是正確的代碼！

- (void)loadScrollViewWithPage:(int)page { 
if (page < 0) return; 
if (page >= kNumberOfPages) return; 

// replace the placeholder if necessary 
if (page == 0){ 
MyViewController *controller = [viewControllers objectAtIndex:page]; 
if ((NSNull *)controller == [NSNull null]) { 
    controller = [[MyViewController alloc] initWithPageNumber:page]; 
    [viewControllers replaceObjectAtIndex:page withObject:controller]; 

} 
    if (nil == controller.view.superview) { 
     CGRect frame = scrollView.frame; 
     frame.origin.x = frame.size.width * page; 
     frame.origin.y = 0; 
     controller.view.frame = frame; 
     [scrollView addSubview:controller.view]; 
} 
} 
if (page == 1){ 
    PageOne *controller = [viewControllers objectAtIndex:page]; 
    if ((NSNull *)controller == [NSNull null]) { 
     controller = [[PageOne alloc] initWithPageNumber:page]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 

    } 
    if (nil == controller.view.superview) { 
     CGRect frame = scrollView.frame; 
     frame.origin.x = frame.size.width * page; 
     frame.origin.y = 0; 
     controller.view.frame = frame; 
     [scrollView addSubview:controller.view]; 
} 
// add the controller's view to the scroll view 

} 

}

THX對於第一answewr她打開我的心！