如何在 iPhone 中制作无限滚动视图?

问题描述

我有一个 scrollview，其中有 5 个宽度为 88 的图像视图.

I have a scrollview with 5 image views of width 88.

我希望 scrollview 滚动到每个图像视图 (非分页)

I want the scrollview to scroll to each image view (Not Paging)

和

我想在 iPhone 中制作一个无限滚动视图，这意味着当它滚动到最后一个项目时，它会在它旁边显示第一个项目..

I want to make an infinite scrollview in iPhone which means the when it scroll to last item it will display a first item next to it..

我一直在尝试按偏移量，但是当按偏移量移动它时它会停止，而且 我使用了苹果街道滚动条，它不允许我将每个元素停止在中心(就像选择器视图)..>

I have been trying by offset but it stops when move it by offset and also I have used apple street scroller which does not allow me to stop each element in center(just like Picker view)..

推荐答案

首先，我推荐使用 UITableView，这样可以保持较低的内存使用率.我在一个项目中成功使用的方法如下:

First of all, I recommend to use a UITableView so you can maintain the memory usage low. An approach that I had used successfully in a project is the following:

1.列表项

复制单元格的内容，我的意思是如果你有 5 个这样的项目:

Duplicate the content of your cells, I mean if you have 5 items in this way:

|1 |2 |3 |4 |5 |

| 1 | 2 | 3 | 4 | 5 |

您应该在表格末尾添加相同的内容(在具有可重用引擎的表格视图中，这不是什么大问题)，以便看起来像这样:

You should add the same (In a table view with reusable engine that's not a big deal) at the end of the table in order to look like this:

|1 |2 |3 |4 |5 |1 |2 |3 |4 |5 |

| 1 | 2 | 3 | 4 | 5 | 1 | 2 | 3 | 4 | 5 |

2.修改 scrollViewDidScroll 如下:

2. modify the scrollViewDidScroll with the following:

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    if (scrollView == _yourScrollView) {
        CGFloat currentOffsetX = scrollView.contentOffset.x;
        CGFloat currentOffSetY = scrollView.contentOffset.y;
        CGFloat contentHeight = scrollView.contentSize.height;

        if (currentOffSetY < (contentHeight / 6.0f)) {
            scrollView.contentOffset = CGPointMake(currentOffsetX,(currentOffSetY + (contentHeight/2)));
        }
        if (currentOffSetY > ((contentHeight * 4)/ 6.0f)) {
            scrollView.contentOffset = CGPointMake(currentOffsetX,(currentOffSetY - (contentHeight/2)));
        }
    }
}

如果您几乎到达滚动的最后，上面的代码将滚动位置移动到顶部；或者，如果您几乎在顶部，则将您移至底部...

The code above move the scroll position at top if you almost reach the final of the scrolling; Or if you are almost on the top, moves you to the bottom...

3.就是这样.

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