I have an array that starts out empty but is filled with PFFiles (image data) with a PFQuery. A UIImageView has its image set using the data in the PFFile Array. However, if the array is empty then there is an error saying array index is out of range. Therefore, I need something testing to see if array is empty and I can't find a way to do that.
var imageFiles = [PFFile]()
And then in the viewDidLoad
self.imageFiles[self.imageCounter].getDataInBackgroundWithBlock{
(imageData, error) -> Void in
if error == nil {
let image = UIImage(data: imageData!)
self.mainPic.image = image
}else {
}
}
I would like to be able do something like:
If let testVariable = self.imageFiles[self.imageCounter] as PFFile {
}
Or more simply:
If self.imagesFiles[self.imageCounter] == nil {
}
But neither of those work
The problem is you're going out of the bounds of the array, as you said. You can void this by checking the size of the array before trying to access an element. The following should do the trick:
if (self.imagesFiles.count > self.imageCounter) {
//myImage = self.imageFiles[self.imageCounter];
}
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
I am struggling to return a UIImage from a Parse Function.
I'm fairly new to return functions but I have got Parse and well now I am trying to make a global function which I can reference in MVVM schema instead of continuously repeating the code throughout my app.
The function works perfectly without the return statement added (-> UIImage), I just can't get a UIImage then.
func fetchImage(imageFile : PFFile) -> UIImage
{
var image : UIImage!
imageFile.getDataInBackground { (data, error) in
if error == nil
{
image = UIImage(data: data!)
}
else
{
print(error!)
image = default-img
}
}
return image
}
I'm sure it's a simple error I'm making, I just can't seem to find anything about adding a return statement to a parse function.
I'm trying to make a slideshow with this library
https://github.com/zvonicek/ImageSlideshow
So i'm making a query, i bring some images and i append them here
var sliderArray = [UIImage]()
var testimg:UIImage!
let idaki = recipeObj.objectId
let pointer2 = PFObject(outDataWithClassName:"Recipes", objectId: idaki!)
let galquery = PFQuery(className:"sliderRecipes")
galquery.whereKey("recipe", equalTo: pointer2)
galquery.findObjectsInBackgroundWithBlock {
(objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
// The find succeeded.
print("Successfully retrieved \(objects!.count) scores.")
// Do something with the found objects
if let objects = objects {
for object in objects {
count += 1
let glrimg = object["sliderImage"] as! PFFile
glrimg.getDataInBackgroundWithBlock {
(imageData3: NSData?, error: NSError?) -> Void in
if error == nil {
if let imageData2 = imageData3 {
self.testimg = UIImage(data:imageData2)
print(self.testimg)
print(self.sliderArray)
self.sliderArray.append(UIImage(data:imageData2)!)
}
if count == objects.count { print(self.sliderArray) }
}
}
// print("test")
// print(self.sliderPinakas)
}
}
} else {
// Log details of the failure
print("Error: \(error!) \(error!.userInfo)")
}
And after all this i DONT have an array with images. In the print above it first shows the empty array and after that it shows the prints of UI Images that i want to show them like this to a slider
slideshow.setImageInputs([ImageSource(image: UIImage(named: "myImage"))!, ImageSource(image: UIImage(named: "myImage2"))!])
but instead of having to do it with the name, UIImage(named: "myImage"))! i would like to do it this way
self.slider.setImageInputs([ImageSource(image: self.testimg)])
for all the images of the array, cause the above line shows only one.
Is there anyone that could help?
Thanks!
You have pass to self.slider.setImageInputs array of all objects ImageSource [ImageSource(image: self.testimg1), ImageSource(image: self.testimg2), ...] etc., not only one object [ImageSource(image: self.testimg)].
If you add images like:
self.slider.setImageInputs([ImageSource(image: self.testimg)])
self.slider.setImageInputs([ImageSource(image: self.testimg2)])
you'll simply replace first image with second.
Create new array, enumerate all images from sliderArray, and append they to array ImageSource(image: self.testimg1) objects.
Also remember, you have to call this from block glrimg.getDataInBackgroundWithBlock!
add before for
var count = 0
and add inside block
count +=1
if count == objects.count {
print(self.sliderArray)
}.
That will print array when all objects finished loads (they can loads in chaotic order).
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.
I'm successfully pulling in data from Parse into swift, but my images don't seem to be working the way I'm doing it.
In my cellForRowAtIndexPath method, I do the following:
var event: AnyObject? = eventContainerArray[indexPath.row]
if let unwrappedEvent: AnyObject = event {
let eventTitle = unwrappedEvent["title"] as? String
let eventDate = unwrappedEvent["date"] as? String
let eventDescription = unwrappedEvent["description"] as String
let eventImage = unwrappedEvent["image"] as? UIImage
println(eventImage)
if (eventImage != nil){
cell.loadItem(date: eventDate!, title: eventTitle!, description: eventDescription, image: eventImage!)}
else {
let testImage: UIImage = UIImage(named: "test-image.png")!
cell.loadItem(date: eventDate!, title: eventTitle!, description: eventDescription, image: testImage )
}
}
}
return cell
}
I'm using println() with my PFQuery, and I am seeing this as part of the object that's loading in: image = "<PFFile: 0x7fee62420b00>";
So I'm getting title, date, description, etc. all loading fine as part of the above eventContainerArray, but when I look at eventImage, it's nil every time. In the code above, it always defaults to loading test-image.png, being that the image is coming up nil. Am I simply handling that PFFile the improper way? Not sure why it's not working.
Thanks!
Your image is likely a PFFile object. You will need to load it to get an UIImage object from it.
let userImageFile = unwrappedEvent["image"] as PFFile
userImageFile.getDataInBackgroundWithBlock {
(imageData: NSData!, error: NSError!) -> Void in
if error == nil {
let eventImage = UIImage(data:imageData)
// do something with image here
}
}
I'm not familiar with Parse, but given what you're seeing from the println() it looks like what you've received isn't a UIImage but instead some sort of data type. This makes sense; you aren't going to be receiving ObjC objects over the network. So you are getting a file, but when you use the conditional downcast (x as? UIImage) it's returning nil because you don't have a UIImage.
Instead you're going to need to cast to PFFile, and then probably create a UIImage with UIImage(data: file.getData) or something similar. I'm not familiar with exactly how Parse works.
Edit: here's a related question that might be helpful: I can't get image from PFFile