如何在 swift 中将数组传递给 NSNotification

Question

我有以下代码打印更新图像

的 url

override func viewWillAppear(animated: Bool) {
  NSNotificationCenter.defaultCenter().addObserver(self, selector: "assetChange:", name: ALAssetsLibraryChangedNotification, object: nil) }


func assetChange(notification: NSNotification){

  if var info:NSDictionary = notification.userInfo { var url:NSSet = info.objectForKey(ALAssetLibraryUpdatedAssetsKey) as NSSet
      var aurl:NSURL = url.anyObject() as NSURL
        println(aurl)

     }

}

这段代码工作正常，但它只会打印第一个修改过的图像url，但我想要所有修改过的图像列表url（修改过的图像数组）请帮助我

Answer 1

您在使用 url.anyObject() 时从集合中选择了一个对象。相反，您需要从集合中获取所有对象，然后遍历数组。以下代码应该对您有所帮助：

func assetChange(notification: NSNotification) {

    if var info:NSDictionary = notification.userInfo { var url:NSSet = info.objectForKey(ALAssetLibraryUpdatedAssetsKey) as NSSet
        var urls: [NSURL] = url.allObjects as [NSURL]
        for singleUrl in urls {
            println(singleUrl)
        }   
    }
}

如何在 swift 中将数组传递给 NSNotification

how to pass array to NSNotification in swift

nsnotificationcenter

alassetlibrary

swift