Question

我使用this code在UIScrollView中制作重用视图，效果很好。知道如何在UIScrollView中使用重用子视图使这段代码无限滚动吗？

代码

#pragma mark 
#pragma mark - SCROLL VIEW DELEGATE METHOD
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
             [self setNeedsLayout];

            int currentPosition = floor(scrollView.contentOffset.x);
            currentPage = MAX(0,floor(currentPosition / scrollView.frame.size.width));

            if(currentPage != refPage)
            {
                refPage = currentPage;
                if ([arrQLst count] > 0)
                {
                    [self replaceHiddenView];
                }
            }
        }
           - (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView
        {
            if ([arrQLst count] > 0)
            {
                [self replaceHiddenView];
            }
        }
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 -(void)replaceHiddenView
    {
        const double pageWidth =self.frame.size.width;
        NSInteger currentIndex;

        currentIndex = (([self getScrollView].contentOffset.x - pageWidth) / pageWidth) + 1;

        RandomView *currentView = nil;
        RandomView *previousView = nil;
        RandomView *nextView = nil;

        if (CGRectContainsPoint(objRandom1.frame, [self getScrollView].contentOffset))
        {
            currentView = objRandom1;
            previousView = objRandom2;
            nextView = objRandom3;
        }
        else if (CGRectContainsPoint(objRandom2.frame, [self getScrollView].contentOffset))
        {
            currentView = objRandom2;
            previousView = objRandom1;
            nextView = objRandom3;
        }
        else
        {
            currentView = objRandom3;
            previousView = objRandom1;
            nextView = objRandom2;
        }

        currentView.frame = CGRectMake(self.frame.size.width * currentIndex, 0.0, self.frame.size.width, self.frame.size.height);
        [currentView setQuestionData:[arrQLst objectAtIndex:currentIndex]];

        // Now move the other ones around
        // and set them ready for the next scroll
        if (currentIndex < [arrQLst count] - 1)
        {
            nextView.frame = CGRectMake(self.frame.size.width * (currentIndex + 1), 0.0, self.frame.size.width, self.frame.size.height);
            [nextView setQuestionData:[arrQLst objectAtIndex:(currentIndex + 1)]];
        }

        if (currentIndex >= 1)
        {
            previousView.frame = CGRectMake(self.frame.size.width * (currentIndex - 1), 0.0, self.frame.size.width, self.frame.size.height);
            [previousView setQuestionData:[arrQLst objectAtIndex:(currentIndex - 1)]];
        }

        if([arrQLst count] > 0)
            [self checkForRequestForLoadMore:currentIndex];
     }

    -(void)displayViewAtIndex:(NSInteger)index
    {
        @try
        {
            NSInteger count = [arrQLst count];
            if (index >= 0 && index < count)
            {
                Ques *objQ = [arrQLst objectAtIndex:index];
                objRandom1.frame = CGRectMake(self.frame.size.width * index, 0.0,self.frame.size.width,self.frame.size.height);
                [objRandom1 setQuestionData:objQ];
                [[self getScrollView] scrollRectToVisible:CGRectMake(self.frame.size.width * index, 0.0, self.frame.size.width, self.frame.size.height) animated:NO];

                if (index < (count - 1))
                {
                    objQ = [arrQLst objectAtIndex:(index + 1)];
                    objRandom2.frame = CGRectMake(self.frame.size.width * (index + 1), 0.0, self.frame.size.width, self.frame.size.height);
                    [objRandom2 setQuestionData:objQ];
                }

                if (index > 0)
                {
                    objQ = [arrQLst objectAtIndex:(index - 1)];
                    objRandom3.frame = CGRectMake(self.frame.size.width * (index - 1), 0.0, self.frame.size.width, self.frame.size.height);
                    [objRandom3 setQuestionData:objQ];
                }
            }
        }
        @catch (NSException *exception)
        {
            NSLog(@"displayViewAtIndex Exception %s",__PRETTY_FUNCTION__);
        }
    }

Answer 1

以下是制作无限滚动视图的方法。这个应用程序使用可可豆荚，你必须从终端下载。 Github有很多很棒的开源框架，可以随时跟上你的想法。 https://github.com/pronebird/UIScrollView-InfiniteScroll

Answer 2

最后在上面的代码中找到了解决方案并创建了无限的scrollview。这里我们使用相同的代码进行视图的框架设置。

代码：

//这里我在数组的第一个和最后一个索引处添加两个虚拟数据第一个位置我添加的最后一个对象，我最后的对象添加了arrData的第一个对象。当我们创建数据集时第一个对象和最后一个对象的两个虚拟数据。

        if ([arrQLst count] > 1)
        {
            [arrQLst insertObject:[arrQLst lastObject] atIndex:0];
            [arrQLst addObject:[arrQLst objectAtIndex:1]];
        }
        //end
        [self setContentSizeOfScrollView];

- == - == - == - == - == - == - == - == - == - == - == - == - = - = - = - = - = - = - = - = - = - = - = - = - = - = - = - = -

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

    [self setNeedsLayout];

    int currentPosition = floor(scrollView.contentOffset.x);
    currentPage = MAX(0,floor(currentPosition / scrollView.frame.size.width));

    if(currentPage != refPage)
    {
        refPage = currentPage;
        if ([arrQLst count] > 0)
        {
            [self replaceHiddenView];
        }
    }


   if (scrollView.contentOffset.x <= 0.0)
    {
        if ([arrQLst count] > 1)
        {
            [self displayViewAtIndex:([arrQLst count]-2)];
        }
    }
    else if (scrollView.contentOffset.x > (scrollView.frame.size.width * ([arrQLst count] - 1)))
    {
        if ([arrQLst count] > 1)
        {
            [self displayViewAtIndex:1];
        }
    }
}

如何制作无限的UIScrollView？

2 个答案: