滚动视图中的Iphone Web视图

Question

我有一个小应用程序与一些细节控制器。详细控制器是把滚动视图内的Web视图： 下面是详细视图控制器的代码：

- (void)loadScrollViewWithPage:(int)page 

{

if (page < 0) 
    return; 
if (page >= detailTotalJobs) 
    return; 

// replace the placeholder if necessary 
SearchJobDetailWebViewController *controller = [viewControllers objectAtIndex:page]; 
if ((NSNull *)controller == [NSNull null]) 
{ 



    NSLog(@"Vytvaram web controller: %d", page + 1); 

    if (detailJobIndex == page) { 

     controller = [[SearchJobDetailWebViewController alloc] initWithNibName:@"SearchJobDetailWebViewController" bundle:nil page:page url:detailExportUrl]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 

    } else if (detailJobIndex + 1 == page) { 

     controller = [[SearchJobDetailWebViewController alloc] initWithNibName:@"SearchJobDetailWebViewController" bundle:nil page:page url:detailNextExportUrl]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 

    } else { 

     [self performSelector:@selector(downloadData:) withObject:[NSNumber numberWithInt:page] afterDelay:0.1]; 
     //[self downloadData:[NSNumber numberWithInt:page]]; 

     controller = [[SearchJobDetailWebViewController alloc] initWithNibName:@"SearchJobDetailWebViewController" bundle:nil page:page url:nextArray.exportUrl]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 

    } 

} 

// add the controller's view to the scroll view 
if (controller.view.superview == nil) 
{ 

    CGRect frame = scrollView.frame; 
    frame.origin.x = frame.size.width * page; 
    frame.origin.y = 0; 
    controller.view.frame = frame; 
    [scrollView addSubview:controller.view]; 

    //NSDictionary *numberItem = [self.contentList objectAtIndex:page]; 
    //controller.numberImage.image = [UIImage imageNamed:[numberItem valueForKey:ImageKey]]; 
    //controller.myLabel.text = @"Test"; 
} 

}

- (void)scrollViewDidScroll:(UIScrollView *)sender 

{// 我们不不需要UIPageControl和滚动代理之间的“反馈循环” //其中滚动事件是从用户点击页面控制触发从 //委托方法更新。当使用页面控件时，我们使用布尔值来禁用委托逻辑。 if（pageControlUsed） //不执行任何操作 - 滚动是从页面控件启动的，而不是用户拖动 返回; }

// 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; 

NSString *detailTitleText = [NSString stringWithFormat:@"%d/%d", page + 1, detailTotalJobs]; 
[self setTitle:detailTitleText]; 
//[detailTitleText release]; 

// 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 

}

代码由苹果页面控制的启发。

问题是在这里：

if (detailJobIndex == page) { 

     controller = [[SearchJobDetailWebViewController alloc] initWithNibName:@"SearchJobDetailWebViewController" bundle:nil page:page url:detailExportUrl]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 

    } else if (detailJobIndex + 1 == page) { 

     controller = [[SearchJobDetailWebViewController alloc] initWithNibName:@"SearchJobDetailWebViewController" bundle:nil page:page url:detailNextExportUrl]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 

    } else { 

     [self performSelector:@selector(downloadData:) withObject:[NSNumber numberWithInt:page] afterDelay:0.1]; 
     //[self downloadData:[NSNumber numberWithInt:page]]; 

     controller = [[SearchJobDetailWebViewController alloc] initWithNibName:@"SearchJobDetailWebViewController" bundle:nil page:page url:nextArray.exportUrl]; 
     [viewControllers replaceObjectAtIndex:page withObject:controller]; 
     [controller release]; 

    } 

第一部分，如果工作的第二部分正确，因为我对第一个网页视图和第二Web视图的数据。

但是，如果有问题的最后一部分。当我从第二个Web视图滚动到第三个Web视图时，滚动视图显示空白页面。下一页正常工作。 问题在哪里？

Answer 1

只需在调试模式中的大括号中放置一个断点。
控制器是否为零？ 检查您的自定义init方法。

如果出现问题，是否返回零？

[self = super initWithNibName..................]; 
if (!self) return nil; 

// some inits 

return self; 

如果这样做并且控制器为零，请检查您的URL并将其试用到Web浏览器中。它显示吗？

你如何填写你的webView？填充时是否返回错误？没有编码问题返回？

那么，一些代码将有所帮助，但这些迹象是最常见的问题，你可以有。