convert UIImage to NSData and back to UIImage

Question

I have to populate table cell from database and images are on device. I've to store that image in imageDataObject, how to convert that UIImage to NSData. Please suggest, I tried many solution but it's not converting back that NSData to UIImage.

    cell.textLabel.text = [[offlineImageListArray objectAtIndex:indexPath.row] imageName];
    UIImage *thumbnail = [self retrieveImageFromDevice:[[offlineImageListArray objectAtIndex:indexPath.row] imageName]];
    NSData* data = ??????????;
    ImageData *imageDataObject = [[ImageData alloc] initWithImageId:[[offlineImageListArray objectAtIndex:indexPath.row]imageId] 
    imageName:[[offlineImageListArray objectAtIndex:indexPath.row] imageName] imageData:data];
    [imagesArray addObject:imageDataObject];

Answer 1

To convert UIImage to NSData, use either UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality) or UIImagePNGRepresentation(UIImage *image)

To convert NSData to UIImage, use [UIImage imageWithData:imageData]

So your example could look like this:

cell.textLabel.text = [[offlineImageListArray objectAtIndex:indexPath.row] imageName];
UIImage *thumbnail = [self retrieveImageFromDevice:[[offlineImageListArray objectAtIndex:indexPath.row] imageName]];
NSData* data = UIImagePNGRepresentation(thumbnail);
ImageData *imageDataObject = [[ImageData alloc] initWithImageId:[[offlineImageListArray objectAtIndex:indexPath.row]imageId] imageName:[[offlineImageListArray objectAtIndex:indexPath.row] imageName] imageData:data];
[imagesArray addObject:imageDataObject];

References: https://developer.apple.com/LIBRARY/IOS/documentation/UIKit/Reference/UIKitFunctionReference/Reference/reference.html https://developer.apple.com/Library/ios/documentation/UIKit/Reference/UIImage_Class/Reference/Reference.html