将图片保存到照片库并获取已保存图像的URL

Question

我正在尝试将相机拍摄的图像保存到照片库中，并存储已保存图像的URL。我的代码：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

ALAssetsLibrary *library = [[ALAssetsLibrary alloc]init];
[library writeImageToSavedPhotosAlbum:(__bridge CGImageRef)([info objectForKey:UIImagePickerControllerOriginalImage])
                          orientation:ALAssetOrientationUp completionBlock:^(NSURL *assetURL, NSError *error) {
                              if(error == nil) {
                                  _myImageUrl = [NSString stringWithFormat:@"%@",assetURL];
                                  NSLog(@"%@",assetURL);
                              } else NSLog(@"%@",error);
                          }];

[picker dismissViewControllerAnimated:YES completion:nil];}

我的问题是assetUrl始终为空。有什么想法吗？ 谢谢！

- Bogdan

---

可能与这篇文章有关。可能是iOS7的一个bug。ALAssetsLibraryWriteVideoCompletionBlock返回未定义的值 - GregP

Answer 1

最后，在阅读更多内容后，我找到了答案：函数的第一个参数是CGImageRef类型，而(__bridge CGImageRef)并没有达到我的预期效果；但是如果我调用UIImage对象的CGImage方法，它就能正常工作。正确的做法是：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

    ALAssetsLibrary *library = [[ALAssetsLibrary alloc]init];
    CGImageRef image = [[info objectForKey:UIImagePickerControllerOriginalImage] CGImage];
    [library writeImageToSavedPhotosAlbum:image
                              orientation:ALAssetOrientationUp
                          completionBlock:^(NSURL *assetURL, NSError *error) {
                                  if(error == nil) {
                                      _myImageUrl = [NSString stringWithFormat:@"%@",assetURL];
                                      NSLog(@"%@",assetURL);
                                  } else NSLog(@"%@",error);
                              }];

    self.toDoImage.image = [info objectForKey:UIImagePickerControllerOriginalImage];
    [picker dismissViewControllerAnimated:YES completion:nil];
}

- Bogdan