ios - 为 collectionview 声明的数组 null 值可选

Question

我创建了一个数组，它是我的 Collection View 的数据。我试图点击 CollectionViewCell 并播放我的数组的文件组件中包含的声音。我不知道如何播放声音，甚至无法开始，因为我的 xcode 项目中的文件为空值。

错误:线程 1: fatal error :在展开可选值时意外发现 nil

如果我不强制解包文件，它会给我一个错误...

class ViewController: UIViewController {

let sounds : [Sounds] = [Sounds(statement: "A", file: Bundle.main.url(forResource: "A", withExtension: "aifc")!),
                            Sounds(statement: "B", file: Bundle.main.url(forResource: "B", withExtension: "aifc")!),
                            Sounds(statement: "C", file: Bundle.main.url(forResource: "C", withExtension: "aifc")!),
                            Sounds(statement: "D", file: Bundle.main.url(forResource: "D", withExtension: "aifc")!)]

}

extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return sounds.count
    }

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "soundCell", for: indexPath) as! CollectionViewCell
        let Soundz = sounds[indexPath.item]
        cell.cellLabel.text = Soundz.statement

        return cell
    }

}

struct Sounds{
    var statement : String
    var file : URL 
}

Answer 1

看起来您的文件没有附加到项目中。检查附加文件的捆绑资源和目标。在这种情况下，最好使用“lazy var”而不是“let”