ios - 检索多个解析图像(Swift)

Question

下面是我通常如何从我的 Parse.com 检索图像的示例。我现在遇到了这样的情况，我想从 Parse 中检索 20 多张图像，但我正在寻找一种更有效的方法来做到这一点。请有人解释如何在代码中实现它以及我应该如何在 Parse 中存储 20 多个 PFFiles？

func loadData(){
let findDataParse = PFQuery(className: "JobListing")
findDataParse.findObjectsInBackgroundWithBlock{
    (objects: [PFObject]?, error: NSError?) -> Void in
    if (error == nil) {
        for object in objects! {
           let userImageFile = object["ImageOne"] as! PFFile
            let userImageFile1 = object["ImageTwo"] as! PFFile
            let userImageFile2 = object["ImageThree"] as! PFFile
            userImageFile.getDataInBackgroundWithBlock {
                (imageData: NSData?, error: NSError?) -> Void in
                let listingImage1 = UIImage(data:imageData!)
                userImageFile1.getDataInBackgroundWithBlock {
                    (imageData1: NSData?, error1: NSError?) -> Void in
                    let listingImage2 = UIImage(data:imageData1!)
                    userImageFile2.getDataInBackgroundWithBlock {
                        (imageData2: NSData?, error1: NSError?) -> Void in
                        let listingImage3 = UIImage(data:imageData2!)

self.flyerImageLarge1.image = listingImage1
self.flyerImageLarge2.image = listingImage2
self.flyerImageLarge3.image = listingImage3
}}}}}}}

Answer 1

您可以使用 ParseUI 来获得更简洁、更高效的代码。为此，请添加 ParseUI 框架。然后，单击图像并将“类”更改为 PFImageView。 You can see this here.

完成后，您可以轻松设置 PFImageView 的图像:

if let myServerImage = object.valueForKey("imageFromUser") as? PFFile {
        self.myImage.file = myServerImage
        self.myImage.loadInBackground()
    }

其中 myServerImage 是您从 Parse 服务器检索的图像，而 myImage 是 Storyboard中的图像。

在您的情况下，它将是这样的:

func loadData(){
    let findDataParse = PFQuery(className: "JobListing")
    findDataParse.findObjectsInBackgroundWithBlock{
    (objects: [PFObject]?, error: NSError?) -> Void in
    if (error == nil) {
        if let myServerImage = object.valueForKey("ImageOne") as? PFFile {
            self.flyerImageLarge1.file = myServerImage
            self.flyerImageLarge1.loadInBackground()
        }
    if let myServerImage = object.valueForKey("ImageTwo") as? PFFile {
            self.flyerImageLarge2.file = myServerImage
            self.flyerImageLarge2.loadInBackground()
        }
    if let myServerImage = object.valueForKey("ImageThree") as? PFFile {
            self.flyerImageLarge3.file = myServerImage
            self.flyerImageLarge3.loadInBackground()
        }
    }
}

我建议添加 if let 语句，这样当图像不存在时就不会出现错误。