將圖像保存到照片庫並獲取保存圖像的URL

Question

我正在嘗試將圖像從相機保存到照片庫，然后存儲保存圖像的URL。 我的代碼：

- (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];}

我的問題是assetUrl總是NULL。 有任何想法嗎？ 謝謝！

Answer 1

最后，在閱讀了更多內容后，我發現了答案：函數的第一個參數是CGImageRef類型，而(__bridge CGImageRef)沒有達到我的預期; 但是如果我調用UIImage對象的CGImage方法，它就可以了。 正確的方法是：

- (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];
}