UIActivityViewController ipad崩溃

UIActivityViewController在iphone上直接使用如下代码就OK

UIActivityViewController *activityController =

    [[UIActivityViewController alloc] initWithActivityItems:activityItems  applicationActivities:nil];

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

在ipad上必须通过popoverPresentationController才能弹出UIActivityViewController

解决办法是 在 presentController 前面加一句

  if ([activityViewController respondsToSelector:@selector(popoverPresentationController)]) {        activityViewController.popoverPresentationController.sourceView = self.view;    }