Question

func loadThumbnails() {

    let paths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)
    let documentsDirectory:NSString = paths[0] as NSString
    var error:NSError?
    let fileManager = NSFileManager()
    let directoryContent:AnyObject = fileManager.contentsOfDirectoryAtPath(documentsDirectory, error: &error)!

    thumbnails = [QSPhotoInfo]()

    for item:AnyObject in directoryContent {
        let fileName = item as NSString
        if fileName.hasPrefix(kThumbnailImagePrefix) {
            let image = loadImageFromDocumentsDirectory(fileName)
            var photoInfo = QSPhotoInfo()
            photoInfo.thumbnail = image;
            photoInfo.thumbnailFileName = fileName
            thumbnails += photoInfo
        }
    }
}

编译错误如下：

类型'AnyObject'不符合协议'SequenceType'

这个menas是什么？

谁能帮帮我，很多!!!!

Answer 1

Apple在The Swift Programming Language中声明：

for-in循环为范围中的每个项执行一组语句，序列，集合或进展。

现在，directoryContent只是符合协议AnyObject，所以你不能在它上面使用for循环。如果你想这样做，你必须做类似以下的事情：

for item in directoryContent as [AnyObject] {
    //Do stuff
}

Answer 2

contentsOfDirectoryAtPath会返回NSArray，而您将其投放到AnyObject。解决方案是将其投射到[AnyObject]?或NSArray：

let directoryContent: [AnyObject]? = fileManager.contentsOfDirectoryAtPath(documentsDirectory, error: &error)

或

let directoryContent: NSArray? = fileManager.contentsOfDirectoryAtPath(documentsDirectory, error: &error)

然后在for循环之前使用可选的绑定：

if let directoryContent = directoryContent {
    for item:AnyObject in directoryContent {

查看contentsOfDirectoryAtPath文档，它声明它总是返回一个数组 - 所以上面说的可以简化为将返回值解包到swift或objc数组，而不需要使用可选的绑定：

let directoryContent: [AnyObject] = fileManager.contentsOfDirectoryAtPath(documentsDirectory, error: &error)!

或

let directoryContent: NSArray = fileManager.contentsOfDirectoryAtPath(documentsDirectory, error: &error)!

输入＆＃39; AnyObject＆＃39;不符合协议＆＃39; SequenceType＆＃39;

2 个答案: