ios：從系統相簿選取視頻並獲得視頻的縮圖

在UIImagePickerControllerDelegate的函數- (void)imagePickerController:(UIImagePickerController *)picker   didFinishPickingMediaWithInfo:(NSDictionary *)info 中實現：

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

{   

    [picker dismissModalViewControllerAnimated:YES];

    

    NSString *mediaType = [infoobjectForKey:UIImagePickerControllerMediaType];

    if([mediaType isEqualToString:@"public.movie"])

    {

        NSURL *videoURL = [infoobjectForKey:UIImagePickerControllerMediaURL];

        NSLog(@"found a video");

        //擷取視頻的thumbnail     

        MPMoviePlayerController *player = [[[MPMoviePlayerControlleralloc]initWithContentURL:videoURL] autorelease];

        UIImage  *thumbnail = [playerthumbnailImageAtTime:1.0timeOption:MPMovieTimeOptionNearestKeyFrame];

player = nil;

        }

}