xcode iCarousel 线性类型从中心开始

iCarousel Linear Type starts from center

提问by Zeeshan Jan

I would like iCarousel to start appearing from left i.e it should be left aligned. I have found that in case of Linear Carousel it starts from center of the screen.

我希望 iCarousel 从左侧开始出现，即它应该左对齐。我发现在 Linear Carousel 的情况下，它从屏幕中心开始。

How can I make the Linear Carousel to start from left?

我怎样才能让线性旋转木马从左边开始？

采纳答案by Pavel Rudkouski

In my case, I was helped by the use of the method [self.vwCoverFlow scrollToItemAtIndex:2 animated:YES];in my viewDidLoad.

就我而言，[self.vwCoverFlow scrollToItemAtIndex:2 animated:YES];在我的 viewDidLoad 中使用该方法对我有所帮助。

回答by Ankit

If you want a linear scrolling , you can use swipeView class , it is from the same developer as iCarousel but for linear scrolling only . I have used it and it do support left alignment . Its easy to add and used, same as iCarousel

如果您想要线性滚动，您可以使用 swipeView 类，它与 iCarousel 来自同一开发人员，但仅用于线性滚动。我用过它，它确实支持左对齐。它易于添加和使用，与 iCarousel 相同

here is the link for the code https://github.com/nicklockwood/SwipeView

这是代码的链接https://github.com/nicklockwood/SwipeView

回答by Rajarshi

Set the wrap property to YES and return the number of placeholderinCarousel as 2

将 wrap 属性设置为 YES 并将 placeholderinCarousel 的数量返回为 2

回答by zvjerka24

I had the same problem and do it with following hack ;)

我遇到了同样的问题，并通过以下 hack 来解决；)

Problem:I need to have view that display only 3 items that are always left aligned.

问题：我需要的视图只显示 3 个始终左对齐的项目。

Resolution:What I have done is to always make at least 3 items. If I have 0, 1 or 2 items I'm always creating 3, but those that do not need to be shown I'm creating as empty UIView. I always have 2 placeholders, but in some cases one or both are empty.

解决方案：我所做的是始终至少制作 3 个项目。如果我有 0、1 或 2 个项目，我总是创建 3 个，但那些不需要显示的项目我创建为空的 UIView。我总是有 2 个占位符，但在某些情况下，其中一个或两个都是空的。

e.g. If we have 2 items to display, I'm actually creating three, but third one is empty UIView. I'm creating two placeholders and one Item.

例如，如果我们有 2 个项目要显示，我实际上创建了三个，但第三个是空的 UIView。我正在创建两个占位符和一个项目。

• First item is first placeholderat index 0
• Second item is Item
• Third item is second placeholderbut with empty UIView

• 第一项是索引 0 处的第一个占位符
• 第二个项目是项目
• 第三项是第二个占位符，但 UIView 为空

If we have 1 items to display, again I'm creating three, but second and third one are empty UIView. Same as in previous example, I'm creating two placeholders and one Item.

如果我们有 1 个项目要显示，我再次创建三个，但第二个和第三个是空的 UIView。与前面的示例相同，我正在创建两个占位符和一个项目。

• First item is first placeholderat index 0
• Second item is Itembut with empty UIView
• Third item is second placeholderbut with empty UIView

• 第一项是索引 0 处的第一个占位符
• 第二项是Item但 UIView 为空
• 第三项是第二个占位符，但 UIView 为空

Because of this logic I'm always cleaning view when reusing ([v removeFromSuperview]), to be sure it is clean and if new one needs to be displayed I'm adding it ([view addSubview...). Same logic for Itemand Placeholder

由于这个逻辑，我在重用时总是清理视图 ([v removeFromSuperview])，以确保它是干净的，如果需要显示新视图，我正在添加它 ([view addSubview...)。Item和Placeholder 的逻辑相同

If you need to have more than 3 displayed items you can use same logic, but change value 3 to something else. If I'm wrong update me ;)

如果您需要显示 3 个以上的项目，您可以使用相同的逻辑，但将值 3 更改为其他内容。如果我错了，请更新我;)

Here is a part of mine code that works for me ;)

这是我的代码的一部分，对我有用;)

- (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel
{
    return [[self getRecordings] count] > 3? [[self getRecordings] count] - 2: 1;
}

- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
    if (view == nil)
    {
        view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 30)];
    }
    else
    {
        // If reusing remove content from holder view for fake items
        for (UIView *v in view.subviews)
        {
            [v removeFromSuperview];
        }
    }

    if ([[self getRecordings] count] >= 2)
    {
        [view addSubview:[(RecordingItemViewController*)[_recordingItemViewControllers objectAtIndex:index + 1] view]];
    }

    return view;
}

- (NSUInteger)numberOfPlaceholdersInCarousel:(iCarousel *)carousel
{
    return 2;
}

- (UIView *)carousel:(iCarousel *)carousel placeholderViewAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
    if (view == nil)
    {
        view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 30)];
    }
    else
    {
    // If reusing remove content from holder view for fake items
        for (UIView *v in view.subviews)
        {
            [v removeFromSuperview];
        }
    }

    if (([[self getRecordings] count] > 0 && [[self getRecordings] count] < 3 && index == 0) || [[self getRecordings]count] >= 3)
    {
        [view addSubview:[(RecordingItemViewController*)(index == 0? [_recordingItemViewControllers objectAtIndex:0]: [_recordingItemViewControllers lastObject]) view]];
    }

    return view;
}

回答by user2713033

This works for me

这对我有用

    - (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel{

       [carousel scrollToItemAtIndex:photosArray.count/2 animated:YES];

        return [photosArray count];
       }

回答by nahung89

in your case, i would like to suggest using 2 placeholder.

在您的情况下，我建议使用 2 个占位符。

Ex: you have n photos, then you will have (n-2) items and 2 placeholders. - Index of items is from 1 to (n-2). - Index of placeholders is 0 and (n-1). Now we will have some code like this:

例如：您有 n 张照片，那么您将拥有 (n-2) 个项目和 2 个占位符。- 项目索引从 1 到 (n-2)。- 占位符索引为 0 和 (n-1)。现在我们将有一些这样的代码：

#pragma mark iCarousel DataSource

- (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel
{
    //if we have n photos, then number of items is (n-2)
    int count = _movieGalleries.count;
    return count >= 3 ? count - 2 : count;
}

- (NSUInteger)numberOfPlaceholdersInCarousel:(iCarousel *)carousel
{
    //2 placeholder
    return _movieGalleries.count >= 3 ? 2 : 0;
}

#pragma mark iCarousel Delegate
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{ 
   //reuse your view
   UIView *yourview = ...

    //get your data
    //index of item is 1 -> n-2, index of placeholder is 0 and n-1
    Item *item = [_listItems objectAtIndex:index + 1];

    //config your view
    ...
    return yourView;
}

- (UIView*)carousel:(iCarousel *)carousel placeholderViewAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
    //index of placeholder is 0 and n-1
    //Trick: we use viewForItemAtIndex for getting placeholder view
    index = index == 0 ? - 1 : carousel.numberOfItems;
    return [self carousel:carousel viewForItemAtIndex:index reusingView:view];
}

- (void)carousel:(iCarousel *)carousel didSelectItemAtIndex:(NSInteger)index 
{

    //in carousel with placeholder, index of selected item is -1, 0, 1, ..., (n-2). which -1 and (n-2) is index of placeholders. So that we need to increase index by 1
    NSLog("current index: %i", index + 1);
}