小编Gar*_*mal的帖子

我正在尝试使用UIImagePickerController获取从库中拾取的视频的缩略图.

这是我的代码.如果我使用相机录制视频,我可以获得视频的缩略图.但是如果我从图书馆中获取视频,我就无法获得缩略图.谁知道为什么？

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];

    if ([mediaType isEqualToString:(NSString *)kUTTypeMovie])
    {
        NSURL *mediaUrl = [info objectForKey:UIImagePickerControllerMediaURL];

        MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:mediaUrl];
        moviePlayer.shouldAutoplay = NO;
        UIImage *thumbnail = [[moviePlayer thumbnailImageAtTime:0.0 timeOption:MPMovieTimeOptionNearestKeyFrame] retain];
        [imageView setImage:thumbnail];  //imageView is a UIImageView

        [moviePlayer release];
        [thumbnail release];
        [self dismissModalViewControllerAnimated:YES];
    }
}