将图像保存到照片库并获取保存图像的 URL答案

【问题标题】：Saving image to Photo Library and get the URL of the saved image将图像保存到照片库并获取保存图像的 URL
【发布时间】：2014-01-29 20:23:44
【问题描述】：

我正在尝试将图像从相机保存到照片库，然后存储已保存图像的 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 总是NULL。有任何想法吗？谢谢！

【问题讨论】：

可能与这篇文章有关。可能是 iOS7 的错误。 [ALAssetsLibraryWriteVideoCompletionBlock 返回未定义的值][1] [1]：stackoverflow.com/questions/20813540/…

标签： ios objective-c alassetslibrary

【解决方案1】：

终于，在阅读了更多之后，我找到了答案：函数的第一个参数是CGImageRef类型，而(__bridge CGImageRef)没有达到我的预期；但是如果我调用UIImage 对象的CGImage 方法，它就可以工作。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];
}

【讨论】：