I have imported my Parse db to Backendless and I'm seeing that my image content is in relation with data in string format, so when I try to fetch it shows only as string(URL).How can I call or convert url to UIImage.Thank you
See script below :
func fetching() {
let backendless = Backendless()
let query = BackendlessDataQuery()
backendless.persistenceService.of(Menu.ofClass()).find(query, response: { ( menu : BackendlessCollection!) -> () in
let currentPage = menu.getCurrentPage()
print("Loaded \(currentPage.count) Menu objects")
for menu in currentPage as! [Menu] {
print("Menu name = \(menu.name)")
self.name.text = menu.name
self.type.text = menu.type
print("Type = \(menu.type)")
print(menu.image)
}
},
error: { ( fault : Fault!) -> () in
print("Server reported an error: \(fault)")
})
}
You need to download the image file, in a similar manner to how you used to download the PFFile. It's generally a good idea to use a library like SDWebImage to manage the download and caching of the image for you.
Related
I try to do a query with Parse containing a few Strings and Images that will be added to an array. The strings in the array are all in the right order but not the images. I think its probably because some images are smaller than the other ones and so they get appended to the array earlier than they are supposed to. Is there any way to "save" space in the array for the images to keep them in the right order? It's probably not that hard to solve that but I am a Newbie :( Thank you!
query.findObjectsInBackground (block: { (objects:[PFObject]?, error: Error?) -> Void in
for object in objects! {
DispatchQueue.global(qos: .userInteractive).async {
// Async background process
if let imageFile : PFFile = self.bild.append(object.value(forKey: "Bild") as! PFFile) {
imageFile.getDataInBackground(block: { (data, error) in
if error == nil {
DispatchQueue.main.async {
// Async main thread
let image = UIImage(data: data!)
image2.append(image!)
}
} else {
print(error!.localizedDescription)
}
})
}
}
}
})
Your analysis is correct that the requests will complete in non-deterministic order, partly or mostly influenced by the amount of data that must be returned.
Instead of an array to which you append the UIImage (or data), use a mutable dictionary that maps strings to UIImage. A reasonable choice for the string key is the PFFile name.
EDIT I'm not a Swift writer, but I tried to express the idea below (don't depend on it compiling, but I think the idea is sound)
class MyClass {
var objects: [PFObject] = []
var images: [String: UIImage] = [:] // we'll map names to images
fetchObjects() {
// form the query
query.findObjectsInBackground (block: { (objects:[PFObject]?, error: Error?) -> Void in
self.objects = objects
self.fetchImages()
})
}
fetchImages() {
for object in self.objects! {
if let imageFile : PFFile = object["Bild"] as PFFile {
self.fetchImage(imageFile);
}
}
}
fetchImage(imageFile: PFFile) {
imageFile.getDataInBackground(block: { (data, error) in
if error == nil {
self.images[imageFile.name] = UIImage(data: data!)
// we can do more here: update the UI that with image that has arrived
// determine if we're done by comparing the count of images to the count of objects
} else {
// handle error
}
}
}
}
This will get the images in the background and keep them associated with their filenames using a dictionary. The OP code didn't explain what self.bild is, but I assumed it was an instance array of retrieved PFFiles. I replaced this with the images instance var.
Image file order is maintained by the object collection: to get the Nth image, get the Nth object, get it's "Bild" property, that PFFile's name is the key into your images dictionary.
var n = // some index into objects
var object : PFObject = self.objects[n]
var file : PFFile = object["Bild"]
var name : String = file.name
var nthImage = self.images[name] // is nil before fetch is complete
So I have an array of images I've accessed from my xcassets for demonstration purposes. There are 150 images I'm trying to save to my parse server at one time using parse frameworks. Here is the code I have so far. The problem I have is my app cpu goes to 100% in the tests and drops to 0. Also the images aren't saving to parse. I was hoping someone could help me find an efficient way to save 150 images to parse.
var imageNameList: [String] {
var imageNameList2:[String] = [] //[NSMutableArray]()
for i in 0...149 {
let imageName = String(format: "pic_%03d", Int(i))
imageNameList2.append(imageName)
}
return imageNameList2
}
#IBAction func Continue(_ sender: Any) {
for imageName in imageNameList {
var objectForSave:PFObject = PFObject(className: "Clo")
let object:UIImage = UIImage(named: imageName)!
let tilesPF = imageNameList.map({ name in
let data = UIImagePNGRepresentation(object as! UIImage)!
let file = PFFile(data: data)
let tile = PFObject(className: "Tile")
tile["tile"] = file
})
objectForSave["tiles"] = tilesPF
objectForSave.saveInBackground(block: { responseObject, error in
//you'll want to save the object ID of the PFObject if you want to retrieve a specific image later
})
}
}
The trouble is that the tight for-loop launches all of those requests concurrently causing some part of the http stack to bottleneck.
Instead, run the requests sequentially as follows (in my best approximation of Swift)...
func doOne(imageName: String, completion: (success: Bool)->()) {
var objectForSave:PFObject = PFObject(className: "Clo")
let object:UIImage = UIImage(named: imageName)!
// ... OP code that forms the request
objectForSave.saveInBackground(block: { responseObject, error in
success(error == nil)
})
}
func doMany(imageNames: Array<String>, completion: (success: Bool)->()) {
if (imageNames.count == 0) return completion(YES)
let nextName = imageNames[0];
self.doOne(imageName:imageNames[0] completion: {(success: Bool) -> Void in
if (success) {
let remainingNames = imageNames[1..imageNames.count-1]
self.doMany(imageNames: remainingNames completion:completion)
} else {
completion(NO)
})
}
In English, just in case I goofed the Swift, the idea is to factor out a single request into it's own function with a completion handler. Build a second function that takes an array of arguments to the network request, and use that array like a to-do list: do the first item on the list, when it completes, call itself recursively to do the remaining items.
I'm using Alamofire to fetch data from server and then put them in an array of CarType objects which CarType is my struct. what I get from server is name , id and iconUrl. from iconUrls i want to download icons and put them in icon. after that I'll use icon and name in a collection view. my Alamofire request is:
var info = [CarType]()
Alamofire.request(.GET,"url")
.responseJSON { response in
for (_,subJson):(String, JSON) in json["result"]
{
let name = subJson["name"].string
let iconUrl = subJson["icon"].string
let id = subJson["id"].int
info.append(CarType(id: id!, name: name!, iconUrl: iconUrl! , image: UIImage()))
}
my struct is:
import Foundation
import UIKit
struct CarType {
var name : String
var id : Int
var iconUrl : String
var icon : UIImage
}
I want to download images before using them in collectionView.
How can i download images (using AlamofireImage) and put them in related carType icon property?
What you are asking is really bad practice in mobile app. Just a case, for example, you made a request and got like 20 items in an array, and in order to put all UIImages in your models, you have to make 20 more requests, also you even don't know if your users will eventually use (view) those icons or no.
Instead, you could fetch the images when the cell (I guess, you will be displaying those icons in a cell) is displayed, for this purpose you could use libs like SDWebImage(objective c) or Kingfisher(swift) which have extensions for UIImageView to make it simple to fetch and display image on. Those libs can also cache the downloaded image.
Also, another suggestion for object mapping. Currently, you are mapping json to your model manually. There are a lot of good libs to handle that for you, which could automate your object mapping process, for example - ObjectMapper
Hope, this was helpful. Good Luck!
I have done functionalities thing in UITableview, added following in CellForRowIndex method:
getDataFromUrl(urlString){(data,response,error) -> Void in
if error == nil {
// Convert the downloaded data in to a UIImage object
let image = UIImage(data: data!)
// Store the image in to our cache
if((image) != nil){
// Store the image in to our cache
self.imageCacheProfile[urlString] = image
// Update the cell
DispatchQueue.main.async(execute: {
cell.imgvwProfile?.image = image
})
}
else{
cell.imgvwProfile!.image = UIImage(named: "user")
}
}
}
func getDataFromUrl(_ strUrl:String, completion: #escaping ((_ data: Data?, _ response: URLResponse?, _ error: NSError? ) -> Void)) {
let url:URL = URL(string: strUrl)!
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) {data, response, err in
print("Entered the completionHandler")
}.resume()
}
You also need to declare imageCache to store downloaded images.
var imageCache = [String:UIImage]()
You can use above code in your method and it should work just.
I'm trying to add data to my data model so to test it I'm printing the info fetched via Alamofire but my problem is since some data needs to call the api again it becomes null when I print it. Here's my code
Code for getting the person's data
func printAPI(){
swApiHandler.requestSWPApi("http://swapi.co/api/people", completionHandler: {(response, error) in
let json = JSON(response!)
let jsonResult = json["results"]
for (index,person):(String, JSON) in jsonResult{
let name = person["name"].stringValue
let height = person["height"].intValue
let mass = person["mass"].intValue
let hairColor = person["hair_color"].stringValue
let skinColor = person["skin_color"].stringValue
let eyeColor = person["eye_color"].stringValue
let birthYear = person["birth_year"].stringValue
let gender = person["gender"].stringValue
let homeWorldUrl = person["homeworld"].stringValue
let homeWorldNameKey = "name"
let homeWorld = self.getSWApiSpecificValue(homeWorldUrl, strKey: homeWorldNameKey)
print("Name: \(name)")
print("Height: \(height)")
print("Mass: \(mass)")
print("Hair Color: \(hairColor)")
print("Skin Color: \(skinColor)")
print("Eye Color: \(eyeColor)")
print("Birth Year: \(birthYear)")
print("Gender: \(gender)")
print("Home World: \(homeWorld)")
print("------------------------------")
}
})
}
Code for getting the specific value
func getSWApiSpecificValue(strUrl: String, strKey: String) -> String{
var name = ""
swApiHandler.requestSWPApi(strUrl, completionHandler: {(response,error) in
let json = JSON(response!)
print(json[strKey].stringValue)
name = json[strKey].stringValue
})
return name
}
If you want to know the JSON Model here it is
And for running the code here's the output
You should make your api call in background and after it's finished populate your data on main queue.
Just change your code to get specific value to this one:
func getSWApiSpecificValue(strUrl: String, strKey: String) -> String{
var name = ""
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { () -> Void in
swApiHandler.requestSWPApi(strUrl, completionHandler: {(response,error) in
dispatch_async(dispatch_get_main_queue()) {
let json = JSON(response!)
print(json[strKey].stringValue)
name = json[strKey].stringValue
return name
}
})
}
}
In code above first you get make a request to the server in background and if you get response in main queue will populate you variable name.
Also it's better to change your api call function to something like that:
func getDataFromServer(ulr: String, success: (([AnyObject]) -> Void)?, failure: (error: ErrorType) -> Void){
}
In this way you can handle your errors and if success get your data.
I'm working on app to do paged photos inside scrollViews like in the photos app to swipe right to get the old photos and swipe left to get the new photos until the end of photos.
Alright,so i am getting the photos as a multi-diminutional from the web :
imageArray[indexPath.row][0] as? String
Thats in the ViewController1 to show all the images in CollectionView .
When the user press on a photo i do segue and show the image larger in ViewController2 so if swipe left it show the new photos and right to show the old photos which is stored in the array.
but i need to covert my two-dimensional array to one and use it dynamically to be something like this :
pageImages = [UIImage(named:"photo1.png")!,
UIImage(named:"photo2.png")!,
UIImage(named:"photo3.png")!,
UIImage(named:"photo4.png")!,
UIImage(named:"photo5.png")!]
how is it possible to do ?
i could say like :
pageImages = [UIimage(named:thewholearray)] ?
i tried first to convert to one-diminutional array but i failed :
var imageArray : NSArray = []
var mybigarray : NSArray = []
for (var i=0; i<=self.imageArray.count; i++) {
self.mybigarray = self.imageArray[i][0] as! NSArray
}
which generate this casting error :
Could not cast value of type '__NSCFString' (0x196806958) to 'NSArray' (0x196807308).
You can use the map-function to extract the image names from your multi-dimensional array.
var imageNames:[String] = imageArray.map({
$0[0] as! String
})
The map function iterates through all array entries like a for-in-loop.
The statement in the closure determines the new entry of your imageNames array.
EDIT:
If you don't use Swift-Arrays:
var imageNames:NSMutableArray = []
for image in imageArray{
imageNames.addObject(image[0] as! String)
}
I looked at the tutorial and I think this will help with the answer from Daniel. Keep Daniel's Answer and use the URLs from the array with the extension.
Add this to create you images from a URL
extension UIImageView {
public func imageFromUrl(urlString: String) {
if let url = NSURL(string: urlString) {
let request = NSURLRequest(URL: url)
NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) {
(response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in
if data != nil {
self.image = UIImage(data: data)
}
else {
self.image = UIImage()
}
}
}
}
}
Use this in the PagedImageScrollViewController:
newPageView.imageFromUrl(pageImages[page])
pageImages is your array of Strings.