MPMediaPickerController在iPad ios7上非常慢

Question

我试图在iOS7 +上的popover中显示一个MPMediaPickerController，而且非常慢。从第一个NSLog到第二个NSLog大约需要4秒钟。我试过保留选择器，但这没有区别。任何想法都将不胜感激。

- (void) showMediaPickerControllerWithArrowDirection:(UIPopoverArrowDirection)arrow_direction
{
    MPMediaPickerController *self.picker = [[MPMediaPickerController alloc] initWithMediaTypes: MPMediaTypeAnyAudio];

    self.picker.modalPresentationStyle = UIModalPresentationPopover;
    self.picker.delegate = self;
    self.picker.allowsPickingMultipleItems = YES;

    UIPopoverPresentationController *popPresenter = self.picker.popoverPresentationController;
    popPresenter.sourceView = self.view;
    popPresenter.sourceRect = self.view.bounds;
    popPresenter.permittedArrowDirections = arrow_direction;

    NSLog(@"____________________________  about to launch picker ");

    [self.viewController presentViewController:self.picker animated:YES completion:^{
        NSLog(@"____________________________  picker launched ");
    }];
}