Swift Core Data 图片存储与读取

1.首先推出选择拍照还是相册的alert，代码如下：

---

UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle: UIAlertControllerStyleActionSheet];

UIAlertAction *photo = [UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

[self readImageFromCamera];

}];

UIAlertAction *albulm = [UIAlertAction actionWithTitle:@"相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

[self readImageFromAlbum];

}];

UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {

[self dismissViewControllerAnimated:YES completion:nil];

}];

[alert addAction:photo];

[alert addAction:albulm];

[alert addAction:cancel];

[self presentViewController:alert animated:YES completion:nil];

---

2.创建UIImagePickerController,设置imagepicker的sourcetype为camera还是library,设置代理，设置imagepicker的alllowsediting为yes；

3.在imagepicker的代理方法(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary*)info中，取出想要的照片，为info[UIImagePickerControllerEditedImage];info的key海域IImagePickerControllerOriginalImage；

4.对图片进行相应size的压缩

---

image = [self scaleImage:image toSize:CGSizeMake(750, 750)];

- (UIImage *)scaleImage:(UIImage *)image toSize:(CGSize)size {

if (image.size.width > size.width) {

UIGraphicsBeginImageContext(size);

[image drawInRect:CGRectMake(0, 0, size.width, size.height)];

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return newImage;

} else {

return image;

}

}

实体的模型定义：

选择类型

实体的class定义：

@objc(ImageEntity)
class ImageEntity: NSManagedObject {
@NSManaged var imageData: NSData
}
存储：

@IBAction func saveImageToCoreData() {
let delegate = UIApplication.sharedApplication().delegate as AppDelegate
let context = delegate.managedObjectContext

let imageData = UIImagePNGRepresentation(UIImage(named: "image"))

let imageEntity = NSEntityDescription.entityForName("ImageEntity", inManagedObjectContext: context!)
let image = ImageEntity(entity: imageEntity!, insertIntoManagedObjectContext: context!)
image.imageData = imageData

var error: NSError?
if context!.save(&error) == false {
println("failed: \(error!.localizedDescription)")
}
}
读取：

@IBAction func loadImageFromCoreData() {
let delegate = UIApplication.sharedApplication().delegate as AppDelegate
let context = delegate.managedObjectContext

let request = NSFetchRequest(entityName: "ImageEntity")
var error: NSError?
let imageEntities = context?.executeFetchRequest(request, error: &error)

let imageEntity = imageEntities?.first! as ImageEntity
self.imageView.image = UIImage(data: imageEntity.imageData)
}
原文链接：https://blog.csdn.net/zhangao0086/article/details/44499405