将静态单元格添加到UICollectionView [英] Adding a static cell to a UICollectionView

问题描述

我有一个UICollectionView，它显示数组中的单元格。我希望第一个单元格是一个静态单元格，以提示您进入创建流程（最终添加一个新单元格）。

I have a UICollectionView that displays cells from an array. I want the first cell to be a static cell that serves as a prompt to segue into a create flow (eventually adding a new cell).

我的方法是将两个部分添加到我的collectionView中，但是目前我无法弄清楚如何在cellForItemAtIndexPath中返回单元格。这是我的尝试：

My approach would have been to add two sections to my collectionView, but I currently can't figure out how to return a cell within cellForItemAtIndexPath if I do so. This is my attempt:

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    if indexPath.section == 0 {
        let firstCell = collectionView.dequeueReusableCellWithReuseIdentifier("createCell", forIndexPath: indexPath) as! CreateCollectionViewCell
        firstCell.imageView.backgroundColor = UIColor(white: 0, alpha: 1)
        return firstCell
    } else if indexPath.section == 1 {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("mainCell", forIndexPath: indexPath) as! MainCollectionViewCell
        cell.imageView?.image = self.imageArray[indexPath.row]
        return cell
    }
}

此问题是我必须在函数末尾返回一个单元格。它似乎不会作为if条件的一部分返回。感谢您的帮助！

The problem with this is that I have to return a cell at the end of the function. It seems that it won't be returned as part of an if condition. Thanks for helping!

推荐答案

详细讨论Dan的注释，该函数必须返回 UICollectionViewCell 。现在，编译器可以看到 indexPath.section 既不为0也不为1的代码路径。如果发生这种情况，您的代码将不返回任何内容。没关系，这永远不会在您的应用程序中逻辑上发生。

Elaborating on Dan's comment, the function must return an instance of UICollectionViewCell. At the moment the compiler can see a code path where indexPath.section is neither 0 nor 1. If this occurs, your code returns nothing. It doesn't matter that this will never occur logically in your app.

最简单的解决方法是将 else if更改为 else 。像这样：

The easiest way to fix it is to just change the "else if" to an "else". As in:

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    if indexPath.section == 0 {
        let firstCell = collectionView.dequeueReusableCellWithReuseIdentifier("createCell", forIndexPath: indexPath) as! CreateCollectionViewCell
        firstCell.imageView.backgroundColor = UIColor(white: 0, alpha: 1)
        return firstCell
    } else { // This means indexPath.section == 1
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("mainCell", forIndexPath: indexPath) as! MainCollectionViewCell
        cell.imageView?.image = self.imageArray[indexPath.row]
        return cell
    }
}

现在，如果只有两个代码路径，并且都返回一个单元格，那么编译器会更快乐。

Now if there are only two code paths, and both return a cell, so the compiler will be happier.

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