This is probably a ridiculous question but I just can't figure it out for the life of me. I have a class which subclasses NSObject which has a property called image setup, like this:
#property (strong, nonatomic) UIImage *image;
Somewhere else I initialize the class and attempt to set the image in the class, like this:
UIImage *image = [UIImage imageNamed:#"Test"];
Class *item = [[Class alloc] init];
item.image = image;
But when I try to call item.image it is always nil.
The image called Test is in the project and is used elsewhere so I know it has access to the image, but for some reason it isn't being copied to the instance of my class. I have put NSLog messages and breakpoints directly after setting the image which have shown it to be nil as well as using commands via the debugger which have also shown the image in the class to be nil while the UIImage I create to copy is not nil.
I know I am doing something wrong but I have searched and can't figure out what it is.
Thanks for looking, any help is much appreciated.
edit:
I am trying to access the image from a method inside of the class.
- (void)save {
if (self.image != nil) {
// do some stuff
} else {
NSLog(#"image is nil");
}
}
And it is always coming up nil.
edit 2:
Thanks again everyone. I figured out what the problem was. I was overriding the setters/getters which was causing the issue.
Is it a .png file? Try doing it like this:
UIImage *image = [UIImage imageNamed:#"Test.png"];
I have a prepareForSegue that passes an image like this to the next viewController
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
WizardPreview *controller = [segue destinationViewController];
controller.myPicture = myPicture;
}
On the viewWillAppear of the viewController being presented I have a like like this
CGImageRef imageRef = [self.myPicture CGImage];
the result is nil
The strange part is that self.myPicture is not nil, but self.myPicture.CGImage is.
Any reason for that?
NOTE: myPicture is not nil when it is passed and even from viewWillAppear, I test and I see that self.myPicture is not nil.
NOTE 2: this is a code compiled for iOS 7 running on an iPhone with iOS 8.
You haven't posted enough code to say for sure. The three most likely options are:
If myPicture is nil in the prepareForSegure:sender: method
If WizardPreview's myPicture property is weak
If the UIImage is not backed by a CGImage (for example, if it's backed by a CIImage)
If #3 is true, you can create a CGImage directly from a CIImage (sample code here).
I'm trying to learn objective-c and app design for Xcode through books and example, but can't seem to understand how to create a global property for a UIImage, set an image to that property, and then access that UIImage in a different method.
In my FirstViewController.m file, I added the following lines:
#interface FirstViewController ()
#property (strong, nonatomic) UIImage *workingImage;
#end
#implementation FirstViewController
- (IBAction)myMethod1:(id)sender {
... bunch of code ...
UIImage *workingImage = [info objectForKey:UIImagePickerControllerOriginalImage];
}
- (IBAction)button press:(id)sender {
CGContextRef ctx;
CGImageRef imageRef = [self.workingImage CGImage];
...bunch of code...
}
So basically I am trying to create an image variable called workingImage that I set in my method to be an actual image, and then which gets used by CGImageRef after the user pressed the button. However I don't think I have things setup correctly, because imageRef never gets set to my image.
Can someone please show me what I'm doing wrong? (And FYI, this is a code snippet from a very simple app in which the user takes a photo and then I edit it's pixels)
Here you're assigning the image to a local variable:
UIImage *workingImage = [info objectForKey:UIImagePickerControllerOriginalImage];
when what you want is to set the image to the property:
self.workingImage = [info objectForKey:UIImagePickerControllerOriginalImage];
I have a view controller that allows me to add a name, image, and date..the name and date are sent back to the table view controller and displayed..I then have a edit view controller that shows when a populated cell is clicked...
my save method:
-(IBAction)save:(id)sender {
NSData *imageData = UIImagePNGRepresentation(_imageview.image);
[self.currentPlayer setValue:imageData forkey:#"playerPic"];
[self.delegate addPlayerViewControllerDidSave];
}
my delegate is calling the save:&error so i wont paste that code
I believe this is working but my question is how do I have that image display on the edit view controller
my name and date information is passing but not the image
I have a UIImageView and I am attempting something like that but I understand those are two different pointer types and wont work
-(void)viewDidLoad {
firstnameTextField.text = [self.currentPlayer playerName];
editImage.image = [self.currentPlayer playerPic];
}
any help would be appreciated
You need to create a UIImage from your NSData object as follows:
[UIImage imageWithData:[self.currentPlayer playerPic]]
Is it possible to read the name of an UIImageView's UIImage
that's presently stored in the UIImageView?
I was hoping you could do something kind of like this, but haven't figured it out.
NSString *currentImageName = [MyIImageView getFileName];
you can use setAccessibilityIdentifier method for any subclass of UIView
UIImageView *image ;
[image setAccessibilityIdentifier:#"file name"] ;
NSString *file_name = [image accessibilityIdentifier] ;
Nope. You can't do that.
The reason is that a UIImageView instance does not store an image file. It stores a displays a UIImage instance. When you make an image from a file, you do something like this:
UIImage *picture = [UIImage imageNamed:#"myFile.png"];
Once this is done, there is no longer any reference to the filename. The UIImage instance contains the data, regardless of where it got it. Thus, the UIImageView couldn't possibly know the filename.
Also, even if you could, you would never get filename info from a view. That breaks MVC.
No no no… in general these things are possible. It'll just make you feel like a dirty person. If you absolutely must, do this:
Create a category with your own implementation of +imageNamed:(NSString*)imageName that calls through to the existing implementation and uses the technique identified here (How do I use objc_setAssociatedObject/objc_getAssociatedObject inside an object?) to permanently associate imageName with the UIImage object that is returned.
Use Method Swizzling to swap the provided implementation of imageNamed: for your implementation in the method lookup table of the Objective-C runtime.
Access the name you associated with the UIImage instance (using objc_getAssociatedObject) anytime you want it.
I can verify that this works, with the caveat that you can't get the names of UIImage's loaded in NIBs. It appears that images loaded from NIBs are not created through any standard function calls, so it's really a mystery to me.
I'm leaving the implementation up to you. Copy-pasting code that screws with the Objective-C runtime is a very bad idea, so think carefully about your project's needs and implement this only if you must.
There is no native way to do this; however, you could easily create this behavior yourself.
You can subclass UIImageView and add a new instance variable:
NSString* imageFileName;
Then you could override setImage, first setting imageFileName to the filename of the image you're setting, and then calling [super setImage:imageFileName]. Something like this:
-(void) setImage:(NSString*)fileName
{
imageFileName = fileName;
[super setImage:fileName];
}
Just because it can't be done natively doesn't mean it isn't possible :)
if ([imageForCheckMark.image isEqual:[UIImage imageNamed:#"crossCheckMark.png"]]||[imageForCheckMark.image isEqual:[UIImage imageNamed:#"checkMark.png"]])
{
}
Nope. No way to do that natively.
You're going to have to subclass UIImageView, and add an imageFileName property (which you set when you set the image).
Neither UIImageView not UIImage holds on to the filename of the image loaded.
You can either
1: (as suggested by Kenny Winker above) subclass UIImageView to have a fileName property or
2: name the image files with numbers (image1.jpg, image2.jpg etc) and tag those images with the corresponding number (tag=1 for image1.jpg, tag=2 for image2.jpg etc) or
3: Have a class level variable (eg. NSString *currentFileName) which updates whenever you update the UIImageView's image
Or you can use the restoration identifier, like this:
let myImageView = UIImageView()
myImageView.image = UIImage(named: "anyImage")
myImageView.restorationIdentifier = "anyImage" // Same name as image's name!
// Later, in UI Tests:
print(myImageView.restorationIdentifier!) // Prints "anyImage"
Basically in this solution you're using the restoration identifier to hold the image's name, so you can use it later anywhere. If you update the image, you must also update the restoration identifier, like this:
myImageView.restorationIdentifier = "newImageName"
I hope that helps you, good luck!
This code will help you out:-
- (NSString *)getFileName:(UIImageView *)imgView{
NSString *imgName = [imgView image].accessibilityIdentifier;
NSLog(#"%#",imgName);
return imgName;
}
Use this as:-
NSString *currentImageName = [self getFileName:MyIImageView];
In short:
uiImageView.image?.imageAsset?.value(forKey: "assetName")
UIImage has an imageAsset property (since iOS 8.0) that references the UIImageAsset it was created from (if any).
UIImageAsset has an assetName property that has the information you want. Unfortunately it is not public, hence the need to use value(forKey: "assetName"). Use at your own risk, as it's officially out of bounds for the App Store.
Yes you can compare with the help of data like below code
UITableViewCell *cell = (UITableViewCell*)[self.view viewWithTag:indexPath.row + 100];
UIImage *secondImage = [UIImage imageNamed:#"boxhover.png"];
NSData *imgData1 = UIImagePNGRepresentation(cell.imageView.image);
NSData *imgData2 = UIImagePNGRepresentation(secondImage);
BOOL isCompare = [imgData1 isEqual:imgData2];
if(isCompare)
{
//contain same image
cell.imageView.image = [UIImage imageNamed:#"box.png"];
}
else
{
//does not contain same image
cell.imageView.image = secondImage;
}
You can use objective c Runtime feature for associating imagename with the UImageView.
First import #import <objc/runtime.h> in your class
then implement your code as below :
NSString *filename = #"exampleImage";
UIImage *image = [UIImage imagedName:filename];
objc_setAssociatedObject(image, "imageFilename", filename, OBJC_ASSOCIATION_COPY);
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
//You can then get the image later:
NSString *filename = objc_getAssociatedObject(imageView, "imageFilename");
Hope it helps you.
Get image name Swift 4.2
There is a way if you want to compare button image names that you have in assets.
#IBOutlet weak var extraShotCheckbox: UIButton!
#IBAction func extraShotCheckBoxAction(_ sender: Any) {
extraShotCheckbox.setImage(changeCheckBoxImage(button: extraShotCheckbox), for: .normal)
}
func changeCheckBoxImage(button: UIButton) -> UIImage {
if let imageView = button.imageView, let image = imageView.image {
if image == UIImage(named: "checkboxGrayOn") {
return UIImage(named: "checkbox")!
} else {
return UIImage(named: "checkboxGrayOn")!
}
}
return UIImage()
}
Swift 3
First set the accessibilityIdentifier as imageName
myImageView.image?.accessibilityIdentifier = "add-image"
Then Use the following code.
extension UIImageView {
func getFileName() -> String? {
// First set accessibilityIdentifier of image before calling.
let imgName = self.image?.accessibilityIdentifier
return imgName
}
}
Finally, The calling way of method to identify
myImageView.getFileName()
I have deal with this problem, I have been solved it by MVC design pattern, I created Card class:
#interface Card : NSObject
#property (strong,nonatomic) UIImage* img;
#property (strong,nonatomic) NSString* url;
#end
//then in the UIViewController in the DidLoad Method to Do :
// init Cards
Card* card10= [[Card alloc]init];
card10.url=#"image.jpg";
card10.img = [UIImage imageNamed:[card10 url]];
// for Example
UIImageView * myImageView = [[UIImageView alloc]initWithImage:card10.img];
[self.view addSubview:myImageView];
//may you want to check the image name , so you can do this:
//for example
NSString * str = #"image.jpg";
if([str isEqualToString: [card10 url]]){
// your code here
}
use below
UIImageView *imageView = ((UIImageView *)(barButtonItem.customView.subviews.lastObject));
file_name = imageView.accessibilityLabel;
The code is work in swift3 - write code inside didFinishPickingMediaWithInfo delegate method:
if let referenceUrl = info[UIImagePickerControllerReferenceURL] as? NSURL {
ALAssetsLibrary().asset(for: referenceUrl as URL!, resultBlock: { asset in
let fileName = asset?.defaultRepresentation().filename()
print(fileName!)
//do whatever with your file name
}, failureBlock: nil)
}