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.我要存储该图像imageDataObject,如何将其转换UIImage为NSData.请建议,我尝试了许多解决方案,但它不转换回该NSData给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

要转换UIImage为NSData,请使用UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality)或UIImagePNGRepresentation(UIImage *image)

要转换NSData为UIImage,请使用[UIImage imageWithData:imageData]

所以你的例子看起来像这样:

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];

参考文献: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

Answer 2

试试这个:

用它来转换UIImage为NSData.

  NSData *imagedata = UIImagePNGRepresentation(thumbnail);

尝试将此图像数据转换回来 UIImage

  UIImage *image= [UIImage imageWithData:imagedata];