I am using SwiftUI and Realm.
I want to save an Image to the database. The image is a photo taken from the device's camera and is not stored in the gallery.
It's my understanding that I need to convert the image to NSData, but I can only find syntax that works with UIImage.
I tried
let uiImage: UIImage = image.asUIImage()
but get this error:
Value of type 'Image?' has no member 'asUIImage'
What am I doing wrong here, how can I have an Image to Realm local database?
EDIT: Thanks for the suggested "possible duplicate", but no: the duplicate (which I have already seen prior to making my post) is for UIImage (UIKit). I am using Image (SwiftUI).
The struct Image is only a building block for the UI in Swift UI and it is not an object that represents the literal image, but rather something that displays some image.
The common approach, is to see how you create Image - where do you get the actual image from - and to use the source, the image itself to save it.
Just as side note, I wanted to mention that storing data blobs in Realm database can be extremely slow and more commonly used and fast approach is to write files to disk and to store only the names of those files in the database.
Elaborating on this approach, you can:
create a folder to store your images in Library path in user domain mask
You can read about iOS Sandbox file system and where you can store stuff at Apple File System Programming Guide.
For our purposes, it will suffice to this method.
let imagesFolderUrl = try! FileManager.default.url(for: . applicationSupportDirectory, in: .userDomainMask)
.appendingPathComponent("images_database")
You should check if this directory exists and create it if it doesn't - there's plenty of information about this online.
Then, when you have an image Data, you give it a name, you create a URL that will point to where it will be stored and then you write it.
let imageData: Data
let imageName = "some new name for this particular image - maybe image id or something"
let imageUrl = imagesFolderUrl.appendingPathComponent(imageName)
imageData.write(to: url) // Very slow operation that you should perform in background and not on UI thread
Then, you store the name of the image in the Realm database
Then, when you pull a record from Realm database and see the name of the image, you can construct the url again and read a Data from it
let record: RealmRecord
let imageName = record.imageName
let url = imagesFolder.appendingPathComponent(imageName)
let data = Data(url: imageName)
That's overly simplifying it.
I've searched and found some ways where I can get the video asset/file of the LivePhoto asset. But what those methods do are as follows:
They somehow get the resources(PHAssetResource) for the LivePhoto asset
Select the specific video resource(PHAssetResource) from previously found resources.(Ex: resource.type==PHAssetResourceTypePairedVideo)
Save the resource data to a new File(!)
Get the URL for the newly created File.
But, what I want to know, is there any way I can get the URL for the originally stored file URL, without creating a new File?
[For other types of photos/videos I'm able to get the URLs of the originally stored files. The problem is with the video of the LivePhoto asset.]
I have found a way to directly get the original URL of the file. There is no need to save the file contents in a new file. (Tested on iOS12+)
We first get the file URL of associated Image of the LivePhoto.
asset.requestContentEditingInput(with: nil) { (editingInput, info) in
if let input = editingInput, let imgUrl = input.fullSizeImageURL {
// use imgUrl
}
}
The Video file is stored in the same directory as the image file. So, we use the Image URL but with different extension to find the Video file of the LivePhoto. The video file extension is either .mov or .MOV.
if let videoPath = (imagePath.deletingPathExtension as NSString).appendingPathExtension("MOV") {
let videoUrl = URL(fileURLWithPath: videoPath)
// check if file exist and use
// If MOV(Uppercase) extension file doesn't exist check for mov(lowercase) extension similarly
}
Apple's recommendation:
In apps that run in iOS 8 and later, use the WKWebView class instead of using UIWebView.
Thus, I have replaced my good old UIWebView with a shiny new WKWebView. But what I thought to be an easy exercise (simply swapping the classes and replacing the delegate methods) turned out to be a real mess.
The Problem
When I load an HTML string using
loadHTMLString(String, baseURL: URL?)
the web view loads and renders the pure HTML but it doesn't load any images or CSS files referenced inside the htmlString.
This happens only on a real device!
In Simultor all referenced resources are loaded correctly.
Example
I have defined a simple htmlString in my view controller class:
let imageName = "image.png"
let libraryURL: URL // The default Library URL
var htmlString: String {
return "<html> ... <img src=\"\(imageName)\" /> ... </html>"
// "..." represents more valid HTML code incl. header and body tags
}
The image is stored in the root Library folder so its URL is:
let imageURL = libraryURL.appendingPathComponent(imageName)
Now I load the htmlString into the web view:
webView.loadHTMLString(htmlString, baseURL: libraryURL)
and it doesn't load the image even though the baseURL is set correctly.
Ideas for a Solution
Maybe WKWebView has a problem with resolving relative paths so my first idea was to use absolute paths inside the HTML string instead.
→ ❌ Doesn't work.
Two answers to another SO post suggested that using
loadFileURL(URL, allowingReadAccessTo: URL)
instead of loadHTMLString(...) works in iOS 9+.
→ ✅ That works.
However, I cannot use solution 2 because my HTML files are encrypted and the decrypted files must not be stored on the disk.
Question
Is there any way to load local resources like images and styles using the WKWebView's
loadHTMLString(String, baseURL: URL?)
function? Or is still a bug in iOS 9+?
(I just cannot believe that Apple provides and recommends using a web view that cannot load any local web content from inside an HTML string?!)
Without taking a look at your actual project it's difficult to give some hundreed percent sure advices.
However:
class ViewController: UIViewController {
var webView = WKWebView()
override func viewDidLoad() {
super.viewDidLoad()
webView.translatesAutoresizingMaskIntoConstraints = false
let views = [
"webView" : webView
]
view.addSubview(webView)
var constraints = NSLayoutConstraint.constraintsWithVisualFormat("H:|[webView]|", options: [.AlignAllLeading, .AlignAllTrailing], metrics: nil, views: views)
constraints.appendContentsOf(NSLayoutConstraint.constraintsWithVisualFormat("V:|[webView]|", options: [.AlignAllTop, .AlignAllBottom], metrics: nil, views: views))
NSLayoutConstraint.activateConstraints(constraints)
let path = NSBundle.mainBundle().pathForResource("ios - WKWebView fails to load images and CSS using loadHTMLString(_, baseURL_) - Stack Overflow", ofType: "htm")
let url = NSURL(fileURLWithPath: path!)
webView.loadHTMLString(try! String(contentsOfURL: url), baseURL: url.URLByDeletingLastPathComponent)
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I think the key point here is baseUrl parameter, you should setup it correctly. In my case i've used html's url without last path component - e.g. containing folder. This works fine on both device & simulator - check device snapshot. I've uploaded sample project to https://github.com/soxjke/WKWebViewTest so you can take a look (i've removed codesigning info from git)
So, to recap - method is working, functionality is working, just you do something wrong with it. To help you get what's wrong with your solutions, i'll add some suggestions:
1. Remember, that simulator filesystem is case-insensitive, device filesystem is case-sensitive. So if you have your filenames in html in lowercase - this won't work on device. 8fFsD.png != 8ffsd.png
2. Remember, that when copying resources, XCode ignores your folder structure. So if your html has <img src="./img/1.png"> and your XCOde project has folder structure like
test.htm
img/
1.png
2.png
After build it will be flattened, so test.htm and 1.png and 2.png will reside on same level
test.htm
1.png
2.png
I'm almost sure, after you verify these two assumptions, you'll get this method working.
I had this problem today, I've found the solution and potentially the cause:
loadHTMLString(String, baseURL: URL?)
This function doesn't allow the rendered HTML to access local media, as far as I'm aware, this is because it would be an injection risk, this could allow rendered HTML to access and manipulate your local file system. With a html string, that could come from anywhere or anyone.
loadFileURL(URL, allowingReadAccessTo: URL)
With this function, you point the WKWebview to the html file in your FileManager, and to the containing folder with 'allowingReadAccessTo'. Because the html is stored within the FileManager, it will allow the rendered HTML to access locally stored media.
If you don't have the html file stored locally for some reason(I assume you do), You could write the html sting into a .html file, then point to the URL of that file. However, this is just subverting Apple's protection, so do it at your own peril (don't do it).
This is just the solution that worked for me and my understanding of why we're having the problem to begin with.
Edit #1: Typo.
Edit #2: I've since found another nuance, When stating the 'allowingReadAccessTo:' URL, if the HTML itself needs to access things in parent folders (ie: .css, .js files), you need to specify the parent folder, not necessarily the location of the HTML itself, this will then implicitly allow access to the child folders as required also. For me, this problem was only apparent on a physical device, this didn't seem to have an effect whilst running in simulator, likely another discrepancy between how permissions work on simulator and a physical device.
Personally, I had to switch to using XWebView as the out-of-the-box behavior of WKWebView does not allow loading of local files. XWebView tricks it by loading up a local web server in the background and directing local traffic thru it. (XWebView is based on top of WKWebView)
Seems a bit overkill, but that is what I ended up having to do.
I've been experimenting with this as well, with similar restrictions, and the problem appears to be that paths aren't resolved unless baseURL references the application bundle. It doesn't work if you, for example, have something in the application's documents.
Edit: I have filed a radar for this rdar://29130863
Well you should be able to use local images and CSS files (and JavaScript files for that matter) with WKWebViews with the function that you have already found. My guess is that the problem is with your baseURL variable.
Update 7.5.2017:
I have completely updated the code from another SO answer of mine that used to be linked to my answer here. I have a working project for loadHTMLString() and .loadFileURL()
Try to create baseURL using:
let baseURL = URL(fileURLWithPath: "#path#")
instead of:
let baseURL = URL(string: "#path#")
The main difference is that the first method adds file:// prefix before the path.
You can base64 encode the images... I know that works. Not sure if it will be appropriate for your use case though.
Kind of funny, I just ran into this problem while doing the opposite - moving from base64 encoded to image files.
When I used UIWebview, I used baseURL as,
let baseUrl = NSURL(string: Bundle.main.path(forResource: "cms", ofType: "html")!)! as URL
webView.loadHTMLString(bodyPage, baseURL: baseUrl)
But for the WKWebView, I used baseURL as
let baseUrl = Bundle.main.bundleURL
webView.loadHTMLString(bodyPage, baseURL: baseUrl)
This works for me.
I know this is quite old already, but I ran into the exact same problem and it took me hours of trials and even to find this thread with the same problem (Xamarin Forms App)
My issue was: parsing remote HTML content into a string and also adding locally saved images (also downloaded dynamically, no resource of the app). On the simulator all works well, but on acutal device the local images are not showing (also no ? or anything indicating an error, just a blank frame). The Xamarin webview also offers the "BaseURL" option which didn't help, also not to use the BaseURL on the custom iOS wkWebView.
The only working solution as pointed out by Scott above, is to write the HTML into a file and then use the "LoadFileUrl" function and allow read access to the base directory. This also works with absolute file paths for images in the HTML (not only relative to the basedir, but of course somewhere within the basedir).
My custom webview renderer to load web and local content looks like this now:
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e) {
base.OnElementPropertyChanged(sender, e);
NSUrl baseURL = new NSUrl(App.dirNews, true);
string viewFile = Path.Combine(App.dirNews, "view.html");
NSUrl fileURL = new NSUrl(viewFile, false);
switch (e.PropertyName) {
case "Url":
System.Console.WriteLine("--- Loading Web page ---");
System.Console.WriteLine("--- " + Element.Url + " ---");
NSUrlRequest myRequest = new NSUrlRequest(new NSUrl(Element.Url), NSUrlRequestCachePolicy.ReloadIgnoringLocalAndRemoteCacheData, 120);
Control.LoadRequest(myRequest);
break;
case "HTML":
System.Console.WriteLine("--- Showing HTTP content ---");
File.WriteAllText(viewFile, Element.HTML, System.Text.Encoding.UTF8);
Control.LoadFileUrl(fileURL, baseURL);
break;
}
}
I was able to reproduce a similar issue. WKWebView loads my images specially if they are located remotely, apart from my app server.
For servers that are not SSL-secured (http instead of https), you can set your info.plist as per below:
App Transport Security Settings
- Allow Arbitrary Loads in Web Content (Set to YES)
- Allow Arbitrary Loads (Set to YES)
The problem was actually in the server. The server application was either:
Changing the image src from "http://IP-or-domain/uploads/file.jpg" to "../../uploads/file.jpg"
- OR -
The image src was "http://localhost/uploads/file.jpg" or "http://127.0.0.1/uploads/file.jpg" instead of "http://YOUR-SERVER-IP-ADDRESS/uploads/file.jpg"
In these cases, the actual device wont be able to locate the image. This only works with iOS Simulator because the virtual device is the same as the server and development machine. It can read LOCALHOST and 127.0.0.1.
In my server, I was using a Rich Text Editor (TinyMCE) and it automatically removes the IP address after it detects that it's the same source.
WKWebView can load image or css file from NSTemporaryDirectory, so you can copy your files to NSTemporaryDirectory, and then load it. It works for me on iOS 14! see this issue. ios-wkwebview-loadhtmlstring-baseurl-fails-to-load-images-and-read-css
It took me a while to figure this out, but based on this answer I got it working:
https://stackoverflow.com/a/73519282/5868066
Try this:
let htmlPath = URL(fileURLWithPath: "")
let htmlDirectory = htmlPath.deletingLastPathComponent()
let htmlString = try! String(contentsOfFile: htmlPath.path, encoding: .utf8)
let baseURL = URL(fileURLWithPath: htmlDirectory)
let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[.zero]
webView.loadFileURL(htmlPath, allowingReadAccessTo: documentsDirectory)
webView.loadHTMLString(htmlString, baseURL: baseURL)
I understand that to get images from the asset catalog i can use UIImage(named: "fileName") to do it.
however, what if i am getting DATA from the XCAsset catalog? I can't figure this out.
I have tried,
let url = NSBundle.mainBundle().URLForResource("fileName", withExtension: nil)
let data = NSData(contentsOfURL: url!)
But it is nil. I do not know how to get data from the XCAssets catalog. If anyone can help me out (googling hasn't helped) please let me know I will be very thankful!
Update:
Why am I trying to get data from an asset catalog? I dragged an animated gif into the asset catalog. And the asset catalog interprets that as DATA. This is why I am trying to get data out of the asset catalog.
Update:
This is a screen shot of my Assets.xcassets folder looks like.
It has a file called "_Loading" and on the right it is considered a "Data set".
I'm not sure how to get the data set from the Assets catalog.
I am going to answer my own question.
Since iOS 9, the Asset Catalog allows more than just Images. They allow Data sets. In order to get data from the Asset Catalog, you must use the NSDataAsset class.
Example: Assume you have an Data Asset named "CoolJSON"
if let asset = NSDataAsset(name: "CoolJSON") {
let data = asset.data
let d = try? NSJSONSerialization.JSONObjectWithData(data, options: [])
}
In this example I turned an NSData object into a json.
NSDataAsset class reference
Load gif image from Assets.xcassets file. That`s same for loading json files.
NEW: 【New Data Set】 crate a data set and rename "funny" in Assets.xcassets folder. all right, the gif file is added to Assets.xcassets folder.
USE:
NSDataAsset *asset = [[NSDataAsset alloc] initWithName:#"funny"];
self.gifImageView.image = [UIImage sd_animatedGIFWithData:asset.data];
(UIImage *)sd_animatedGIFWithData:(NSData *)data: is a UIImage+GIF category for loading gif image in SDWebImage.
Im trying to load(and upload) images in my app(by picture path).
This is working in my simulator. everything works there. only when im trying to do this on the iphone itself it won't work and i see just the empty UIImageviews.
The paths are loaded the same as in the simulator. And originate from:
PHImageManager.defaultManager().requestImageDataForAsset(asset, options: nil)
{
imageData,dataUTI,orientation,info in
cell.setString(info["PHImageFileSandboxExtensionTokenKey"] as String,name:dataUTI as String)
}
And the PHImageFileSandboxExtentionTokenKey is split into the data and the url when loading the image.
this results in the simulator as :
/Users/Twizzler/Library/Developer/CoreSimulator/Devices/3E671415-8B83-44DA-870F-19BF2BC11F8F/data/Containers/Data/Application/8872109F-3784-40EB-BEB6-4E9FDABE013D/Documents/1613945_10200645161051698_4122753901212984922_n.jpg
and in the iphone as:
/private/var/mobile/Media/DCIM/102APPLE/IMG_2607.JPG
Im loading the image like this:
let image = UIImage(named: "/private/var/mobile/Media/DCIM/102APPLE/IMG_2607.JPG")
cell.imageView.image = image
in this case i put the image url hardcoded (this is in the final app an array of images)
I don't get an error or stack trace. When placeing a breakpoint im seeing the image information in the same way as the simulator
as suggested by the answer im now trying to load them as follows:
let image = UIImage(contentsOfFile: "/private/var/mobile/Media/DCIM/102APPLE/IMG_2607.JPG")
cell.imageView.image = image
This isn't working and i can't upload the files
That’s not how imageNamed works—as the documentation states, that looks for an image with the given name inside your app’s bundle. Try imageWithContentsOfFile.
Well i fixed it! after some puzzling days im now using this way to access upload and
cell.imageView.image = UIImage(data: array[indexPath.row][0] as NSData)
This shows the image. I can save the NSData in the CoreData and reload the image on this way.
To lighten the load on the system im using this:
cellData.checked = 1
var imageData = UIImageJPEGRepresentation(cell.imageView.image, 1)
self.array.append([imageData,cellData.imageData] )
let myObj : ViewControllerImagePicker = self.parentViewController as ViewControllerImagePicker
let textfield: UILabel = myObj.amountLabel! as UILabel
textfield.text = String(self.array.count )
cell.textLabel.alpha = 1
this code is being called when there is clicked on a cell. by setting the cellData.imageData i can recall the cells (when clicking back to the collection view)
I do not know if the way im doing it is correct or works with more that 10 files because of data usage problems. But in my case with a max of 6 selected pictures it works like a charm
The simulator works completely different than a real device when it comes to files, the app bundle and sandboxing.
For starters the simulator will let you write to and add or change files in your app bundle. iOS running on a real device won't let you do this.
You can't hardcode any paths in your app. Even if it works today or on your device in test mode that doesn't mean it will work on a released version. And even if it does it could stop working on any update. Apple several times has changed where things are stored and the path structure in the phone. And where you are allowed to write.
Make bundle calls to get the path locations of standard folders.
Use the assets library to load images from the photo library, or to save them there.
There are tons of resources and tutorials online on how to do this.