I want to save and then later retrieve the images I'm saving to my tmp folder, this is my first time using the file-system so please bear with me if I'm hopeless.
Right now, I'm saving the images that are being retrieved like this:
let userImageFile = object["Image"] as PFFile
userImageFile.getDataInBackgroundWithBlock { (imageData: NSData!, error: NSError!) -> Void in
if error == nil {
image = UIImage(data:imageData)
let imageToSave:NSData = UIImagePNGRepresentation(image)
let path = NSTemporaryDirectory() + "MyFile"
imageToSave.writeToFile(path, atomically: true)
}
}
Assuming this is the correct way to save it I also want to retrieve the images. How do I create a reference to the file I want to retrieve. I've only used the userDefaults before, and there you add a name to the file you're saving, I can't see how you would do it when saving to the tmp-folder.
Any suggestions on how to solve this would be appreciated.
Use the path you've created already to retrieve the image later, you can save this path in the userDefaults for instance, or in an array or whatever you like if you don't need it to be stored.
let tempImage = UIImage(contentsOfFile: path)
Make sure you save the image with a suffix though, .png for instance, so the method understands that the what type of image the file is.
Remember to check if there is still an image at the location, as there is no guarantee that the image is there still, since it's in the NSTemporaryDirectory(). I'd recommend reading this article on the subject of temporary directories.
Related
I am saving images to a custom album after either select or camera completion. Obviously, after camera completion, there is only one image, but when a user selects images in the gallery picker, in the completion handler, when I save that image to the custom album, a duplicate is ALWAYS created. Both in the gallery as well as the root photoAlbum. Everywhere, it seems. I cannot reference the ID to see if it was created before, because the ID is being newly created with the placeholder.
Is there a way to get the base image reference ID so that I can associate EVERY image to the original? As I understand it, IOS (I hate ios btw), saves only one actual image and the rest are just pointers to the original image object. If that is the case, I would expect there is a way to get a solid reference to the original Image and from there, I can easily manage assets created from that base image.
public static func addNewImage(_ image:UIImage, toAlbum albumName:String,imageID:String?,onSuccess success:#escaping(String)->Void, onFailure failure:#escaping(Error?)->Void) {
guard let album = self.getAlbum(withName: albumName) else {
failure(SDPhotosHelper.albumNotFoundError)
return
}
var localIdentifier = String();
if(imageID != nil){
if(self.hasImageInAlbum(withIdentifier: imageID!, fromAlbum: albumName)){
failure(SDPhotosHelper.albumNotFoundError)
return;
}
}
PHPhotoLibrary.shared().performChanges({
let albumChangeRequest = PHAssetCollectionChangeRequest(for: album)
let assetCreationRequest = PHAssetChangeRequest.creationRequestForAsset(from: image)
//assetCreationRequest.location = "";
let placeHolder = assetCreationRequest.placeholderForCreatedAsset
albumChangeRequest?.addAssets([placeHolder!] as NSArray)
if placeHolder != nil {
localIdentifier = (placeHolder?.localIdentifier)!
}
}) { (didSucceed, error) in
OperationQueue.main.addOperation({
didSucceed ? success(localIdentifier) : failure(error)
})
}
}
No one bothered to assist with this. Luckily, I was able to find the solution. For any who come across this or the similar one that was also sitting around with the crickets: Choosing a picture causes resave to camera roll here is a solution.
The code I have is to CREATE A NEW ASSET. It is useful only for the saving the image to your custom album after the user has taken a picture with the camera. It is for brand new assets.
However, for existing assets, you do not want to create a new asset. Instead, you want to add the existing asset to the custom album. To do this, you need a different method. Here is the code I created and it seems to be working. Keep in mind that you will have to get the asset ID FIRST, so that you can send it to your method and access the existing asset.
So, in your imagePickerController, you have to determine whether the user chose an existing image or whether the method is being called from a new camera action.
let pickerSource = picker.sourceType;
switch(pickerSource){
case .savedPhotosAlbum, .photoLibrary:
if(let url = info[UIIMagePickerControllerReferenceURL] as? NSURL{
let refURLString = refURL?.absoluteString;
/* value for refURLString looks something like assets-library://asset/asset.JPG?id=82A6E75C-EA55-4C3A-A988-4BF8C7F3F8F5&ext=JPG */
let refID = {function here to extract the id query param from the url string}
/*above gets you the asset ID, you can get the asset directly, but it is only
available in ios 11+.
*/
MYPHOTOHELPERCLASS.transferImage(toAlbum: "myalbumname", withID: refID!, ...)
}
break;
case .camera:
...
break;
}
Now, in your photohelper class (or in any function anywhere, whatever), to EDIT the asset instead of create a new one, this is what I have. I am assuming the changeRequest variable can be ommitted. I was just playing around until I got this right. Going through the completely ridiculous apple docs I was able to at least notice that there were other methods to play with. I found that the NSFastEnumeration parameter can be an NSArray of PHAssets, and not just placeholder PHObjectPlaceholder objects.
public static func transferImage(toAlbum albumName:String, withID imageID:String, onSuccess success:#escaping(String)->Void, onFailure failure:#escaping(Error?)->Void){
guard let album = self.getAlbum(withName: albumName) else{
... failure here, albumNotFoundError
return;
}
if(self.hasImageInAlbum(withIdentifier: imageID, fromAlbum: albunName)){
... failure here, image already exists in the album, do not make another
return;
}
let theAsset = self.getExistingAsset(withLocalIdentifier: imageID);
if(theAsset == nil){
... failure, no asset for asset id
return;
}
PHPhotoLibrary.shared().performChanges({
let albumChangeRequest = PHAssetCollectionChangeRequest(for: album);
let changeRequest = PHAssetChangeRequest.init(for: theAsset!);
let enumeration:NSArray = [theAsset!];
let cnt = album.estimatedAssetCount;
if(cnt == 0){
albumChangeRequest?.addAssets(enumeration);
}else{
albumChangeRequest?.inserAssets(enumeration, at: [0]);
}
}){didSucceed, error) in
OperationQueue.main.addOperation({
didSucceed ? success(imageID) : failure(error);
})
}
}
So, it is pretty much the same, except instead of creating an Asset Creation Request and generating a placeholder for the created asset, you instead just use the existing asset ID to fetch an existing asset and add the existing asset to the addasset/insertasset NSArray parameter instead of a newly created asset
I'm using the DJISDK in iOS to download pictures from the aircraft.
I'm using the downloadSelectedFiles method from PlaybackManager class.
Here is my process callback:
process: { (data, error) in
if data != nil{
if self.downloadedImageData != nil{
self.downloadedImageData!.append(data!)
}else{
self.downloadedImageData = data!
}
}
}
And this is filecompletition callback:
fileCompletion: {
self.downloadedFilesCount += 1
let image = UIImage(data: self.downloadedImageData!)
if let img = image {
self.downloadedImagesArray?.append(img)
}
self.downloadedImageData = nil
}
I'm correctly retrieving the image but without the EXIF data. How can I get that info and add it to the image?
I already downloaded and tried the iOS-MediaManagerDemo and it's the same thing, downloads the image but without the exif data but the official DJI Go app retrieves all the info so there´s must be some way to do it.
There's also a similar issue in their forums regarding empty metadata and downloadSelectedFilesWithPreparation. The user that created the post
also found a solution:
I solved the problem by not converting the NSData into any format instead saved the NSData directly. Using PHAssets and temporary file to store the NSData as PHAssets only accepts data from URL.
Try using fetchFileDataWithOffset:updateQueue:updateBlock (it will be called fetchFileData(with:updateQueue:updateBlock) in Swift)
[...] fetching the media data will return all data for a video or image
Sample code (objc): here
Is it possible to compare to PFFiles?
I am trying to check whether a downloaded PFFile:
let imageFile = object["groupImage"] as PFFile
is equal to a mock data created by me like this:
let imageData = UIImagePNGRepresentation(UIImage(named: "dot.png")!)
uploadMock = PFFile(name: "mock", data: imageData!)
Now it happens when I call the comparison, it will not work.
if (mock?.isEqual(image))!{
print(true)
} else{
print(false)
}
will always give false, even though the images are the same.
It seems like it would be necessary, to download the image before. I tried to work around with checking the filename (it worked used to work until I transferred to another database).
Any ideas?
I want to retrieve the image that is stored in the storage of an user and place it next to his name in a custom UITableViewCell. The problem now is that the tableview will load when the images aren't done downloading (I think?), causing the application to crash because the image array is nil. So what is the correct way to load the tableview? I think, for the user experience, it is important that the tableviewcell image should be shown even if the images aren't done downloading, and present them a default image that is saved in the assists. I thought about making an array with UIImages that links to the default asset of loading an image and changing the image to the profile picture when it is done downloading. But I really have no clue how to do that. This is what I got so far about downloading the image:
let storage = FIRStorage.storage()
let storageRef = storage.reference(forURL: "link.appspot.com")
channelRef?.observeSingleEvent(of: .value, with: { (snapshot) in
if let snapDict = snapshot.value as? [String:AnyObject]{
for each in snapDict{
let UIDs = each.value["userID"] as? String
if let allUIDS = UIDs{
let profilePicRef = storageRef.child((allUIDS)+"/profile_picture.png")
profilePicRef.data(withMaxSize: 1 * 500 * 500) { data, error in
if let error = error {
}
if (data != nil)
{
self.playerImages.append(UIImage (data: data!)!)
}
}
}
let userNames = each.value["username"] as? String
if let users = userNames{
self.players.append(users)
}
}
}
self.tableView.reloadData()
})
This is in the cellForRow
cell.playersImage.image = playerImages[indexPath.row] as UIImage
My rules, haven't changed it from the default rules:
service firebase.storage {
match /b/omega-towers-f5beb.appspot.com/o {
match /{allPaths=**} {
allow read, write: if request.auth != null;
}
}
}
Thank you.
Regarding user experience, you are correct. It is standard to have some sort of default image when loading an image from a URL. A great library to use for image caching and using default assets in its' place is AlamofireImage
Vandan Patel's answer is correct in saying you need to ensure your array is not nil when loading the tableview. You will be given a completion block to handle any extra work you would like to do with your image, using the AlamofireImage library.
This is all assuming you are getting a correct image URL back for your Firebase users.
You should call tableView.reloadData() when the images are done downloading. One important thing, initialize your playerImages as playerImages = [UIImage]() instead of playerImages: [UIImage]!. if it's empty, it wouldn't show your array is nil.
Update:
if let players = playerImages {
//code
}
I have this code to retrieve images from parse data.
How do I query it by creation date? I tried using findObjectsInBackgroundWithBlock but it wont work with a PFFile. What do i do?
Also, as a side question, sometimes when i place the images in a UIImageView they are upside down or sideways. Why?
if let objects = objects as? [PFObject] {
for object in objects {
if let userPicture = object.valueForKey("Image") as? PFFile {
userPicture.getDataInBackgroundWithBlock({ (imageData: NSData?, error: NSError?) -> Void in
if (error == nil)
{
let image = UIImage(data:imageData!)
self.ImageArray.insert(image!, atIndex: 0)
}
else {
self.alert("Error: \(error!) \(error!.userInfo!)", Message: "Make sure you have a secure internet connection")
}
dispatch_async(dispatch_get_main_queue())
{
self.collectionView.reloadData()
println("Finished Pictures")
}
})
}
}}
You have a set of objects which all reference an image file, but probably a set of other things too, and the image can likely be changed. So, the object creation date isn't the same as the image creation date and the image file doesn't know (or at least doesn't expose) it's creation date. You're also currently always adding the images to the start of the array so the position will be set by how big (and therefore how long it takes to download) each image is. Also, trying to download lots of images at the same time could just mean you get lots of timeouts.
So, really you should have a column on your object which holds the date at which the image was updated, and sort the objects by that date. As you download the images you place them into the image array in the same index as the owning object in its array (pad the array out with NSNull so you know what's going on).