ios - 将 UIImage 转换为 NSData 并返回 UIImage

Question

我必须从数据库中填充表格单元格并且图像在设备上。我必须将该图像存储在 imageDataObject 中，如何将 UIImage 转换为 NSData。请建议，我尝试了很多解决方案，但它没有将 NSData 转换回 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

要将 UIImage 转换为 NSData，请使用 UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality) 或 UIImagePNGRepresentation(UIImage *image )

要将 NSData 转换为 UIImage，请使用 [UIImage imageWithData:imageData]

因此您的示例可能如下所示:

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];

引用文献: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