在imagePickerController:didFinishPickingMediaWithInfo:方法中presentModalViewController失效怎么办？

在imagePickerController:didFinishPickingMediaWithInfo:方法中presentModalViewController失效怎么办？

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    [picker dismissModalViewControllerAnimated:NO];
    [self
presentImageCoper:info];
}

-(void)presentImageCoper :(NSDictionary *)info
{
    if (_imageCoperViewController ==
nil)
    {
        _imageCoperViewController = [[NLImageCroperViewController
alloc] init];
    }
    _imageCoperViewController.delegate =
self;
    [_imageCoperViewController
setImageCoperDelegateAndInfo:self
info:info];
    UINavigationController *nav = [[UINavigationController
alloc] initWithRootViewController:_imageCoperViewController];
    nav.navigationBarHidden =
YES;
    [self.navigationController
presentModalViewController:nav animated:YES];
    [nav release];
}

主要就是把 [picker dismissModalViewControllerAnimated:NO];的动画设置为NO。