如何使用ALAsset保存並重新加載圖像？

Question

我正在編寫一個應用程序，讓用戶拍照並將其分配給設備。爲此，我需要能夠存儲拍攝圖片的URL並在之後重新加載圖片。

我知道已經有上多次討論，但奇怪的是沒有Ansers的幫我...

因此，這裏是我的保存圖像代碼：

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{ 
    ALAssetsLibrary * library = [[ALAssetsLibrary alloc] init]; 
    UIImage * image; 

    // Request to save Image 
    if ([picker sourceType] == UIImagePickerControllerSourceTypeCamera) { 
     image = [info objectForKey:UIImagePickerControllerEditedImage]; 
     [library writeImageToSavedPhotosAlbum:[image CGImage] orientation:(ALAssetOrientation)[image imageOrientation] completionBlock:^(NSURL * assertURL, NSError * error){ 
      if (error) { 
       UIAlertView * alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"PictureSaveErrorTitle", @"Title if saving picture fails") 
                   message:NSLocalizedString(@"PictureSaveErrorMessage", @"Message if saving picture fails") 
                   delegate:nil 
                 cancelButtonTitle:NSLocalizedString(@"PictureSaveErrorOK", @"OK if saving picture fails") 
                 otherButtonTitles:nil]; 
       [alert show]; 
      } else { 
       [self setUserImage:[assertURL absoluteString]]; 
       [imageOfDevice setImage:image]; 
      } 
     }]; 
    } else { 
     image = [info objectForKey:UIImagePickerControllerOriginalImage]; 
     [self setUserImage:[[info valueForKey:UIImagePickerControllerReferenceURL] path]]; 
    } 

    [self dismissModalViewControllerAnimated:YES]; 
} 

這是重裝圖片：

if (userImage != nil) { 
     ALAssetsLibrary * library = [[ALAssetsLibrary alloc] init]; 
     [library assetForURL:[NSURL fileURLWithPath:userImage] 
       resultBlock:^(ALAsset * asset){ 
        [imageOfDevice setImage:[UIImage imageWithCGImage:[asset thumbnail]]]; 
       } 
       failureBlock:^(NSError * error){ 
        NSLog(@"cannot get image - %@", [error localizedDescription]); 
       }]; 
} 

有人看到有什麼毛病嗎？

感謝您的幫助，

sensslen

Answer 1

簡單的解決辦法是要傳遞的absoluteString來代替NSURL。

此代碼適用於我在picker中完成。

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init]; 
if([picker sourceType] == UIImagePickerControllerSourceTypeCamera) 
{ 
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage]; 
    [library writeImageToSavedPhotosAlbum:image.CGImage orientation:(ALAssetOrientation)image.imageOrientation completionBlock:^(NSURL *assetURL, NSError *error) 
    { 
     NSLog(@"IMAGE SAVED TO PHOTO ALBUM"); 
     [library assetForURL:assetURL resultBlock:^(ALAsset *asset) 
     { 
      NSLog(@"we have our ALAsset!"); 
     } 
       failureBlock:^(NSError *error) 
     { 
      NSLog(@"Error loading asset"); 
     }]; 
    }]; 
}