objective-c presentViewController position

I have thus UIActivityViewConroller like so:

- (IBAction)Share:(id)sender {

    NSData *pdfData = [NSData dataWithContentsOfFile:self.pdfPath];

    UIActivityViewController * activityController = [[UIActivityViewController alloc] initWithActivityItems:@[pdfData] applicationActivities:nil];

    activityController.popoverPresentationController.sourceView = self.NavBar;

    [self presentViewController:activityController animated:YES completion:nil];

}

My issue is this shows up on the left side of self.NavBar, I would like to position it to the right side, how would I do that ?