NSDefaultRunLoopMode

//成功获得相片还是视频后的回调

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

    NSURL *videoURL = [info objectForKey:UIImagePickerControllerReferenceURL];
    NSLog(@"kong d:-->%@",videoURL);

//这样写的原因是：2016-07-13 15:54:40.574Warning: Attempt to present <SLComposeViewController: 0x109d9d290> on <UIImagePickerController: 0x101802a00> whose view is not in the window hierarchy!  说是view在picker上，但是picker没有了，所以要做的是在picker消失后，在vc的view上显示

    [picker dismissViewControllerAnimated:YES completion:^{

    [self performSelector:@selector(fbShare:) withObject:videoURL afterDelay:0 inModes:[NSArray arrayWithObjects:NSDefaultRunLoopMode, nil]];

    }];

//NSDefaultRunLoopMode 在空闲的时候执行，视频和上传，该处的视频上初和picker会因为线程卡上，所以这样写
}