Updating image and saving it in dictionary - ios

Question

I am getting image as url from dictionary on ViewController A and I have passed that dictionary to ViewController B.I want that if the user has updated the image then it shows the updated image else it shows the previous image and I am doing the following code for it .Kindly check and tell why is it not working as desired and showing the previous image only in every case.
-(void)showUserImage:(NSURL*)imgUrl
{
[ConnectionManager setSharedCacheForImages];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL:imgUrl];
NSURLSession *session = [ConnectionManager prepareSessionForRequest];
NSCachedURLResponse *cachedResponse = [[NSURLCache sharedURLCache] cachedResponseForRequest:request];
if (cachedResponse.data) {
UIImage *downloadedImage = [UIImage imageWithData:cachedResponse.data];
dispatch_async(dispatch_get_main_queue(), ^{
_profileImageView.image = downloadedImage;
});
} else {
NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
NSHTTPURLResponse *res = (NSHTTPURLResponse *)response;
if(res.statusCode == 200){
dispatch_async(dispatch_get_main_queue(), ^{
_profileImageView.image = [UIImage imageWithData:data];
});
}
}];
[task resume];
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo {
if(_profileImageView.image == [_detailsDictionary valueForKey:#"ProfilePictureUrl"]) {
NSLog(#"Th url of image is %#",[_detailsDictionary valueForKey:#"ProfilePictureUrl"]);
}
else {
_profileImageView.image = image;
UIImage *updatedImage = _profileImageView.image;
NSData *imageData = UIImageJPEGRepresentation(updatedImage, 100);
NSString *strEncoded = [imageData base64EncodedStringWithOptions:0];
[_detailsDictionary setObject:strEncoded forKey:#"ProfilePictureUrl"];
[self dismissViewControllerAnimated:YES completion:nil];
}
}

Answer 1

#Dirtydanee, He is absolutely correct, you are doing incompatible comparison between Url and UIImage. So please correct this with following code.
NSData *data1 = UIImagePNGRepresentation(previousImage);
NSData *data2 = UIImagePNGRepresentation(currentImage);
if([data1 isEqualToData:data2]) {
//Do something
} else {
//Do something
}
Convert images into NSData and compare the data.
If you want bit-by-bit comparison Please look at the following link:
Generate hash from UIImage

Answer 2

The problem seems to be in this line:
if(_profileImageView.image == [_detailsDictionary valueForKey:#"ProfilePictureUrl"]) {
You are trying to compare the _profileImageView.image, what is UIImage, with [_detailsDictionary valueForKey:#"ProfilePictureUrl"], what is NSURL instance, coming from the dictionary.
What you could do instead, is checking if the picked image and the profileImage is the same.
if(_profileImageView.image == image) {
// etc..
To clear previously cached images, just call:
[[NSURLCache sharedURLCache] removeAllCachedResponses];
Hope this helps!