Question

In my application:didFinishLauchginWithOptions: I set the default appearances for my controls.

UIImage *transparentImage = [UIImage imageNamed:@"transparent.png"];

[[UIBarButtonItem appearance]setBackgroundImage:transparentImage 
                                       forState:UIControlStateNormal 
                                     barMetrics:UIBarMetricsDefault];

this works great for me as it gives normal UIBarButtonItems a transparent flat look. However there is a button I that is presented from a UIDocumentInteractionController when you press “quick look” that does not have the right appearance.

I believe this is the only barbuttonitem i have that is just an image. Is there a way I can modify this button to give it some contrast so it doesnt look so ugly? even the original background looks ok on against my naviagationbar background.

Answer 1

I ended up implementing

documentInteractionControllerWillBeginPreview, documentInteractionControllerDidEndPreview

In willBegin I retain the right button and set navigationItem’s right button to nil. I do so because in didEnd the view is already shown so resetting the appearance does not take effect untill its added back.

- (void)documentInteractionControllerWillBeginPreview:(UIDocumentInteractionController *)controller
{
    [[UIBarButtonItem appearance] setBackgroundImage:nil forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
    [[UIBarButtonItem appearance] setBackgroundImage:nil forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
    [[UIBarButtonItem appearance] setBackgroundImage:nil forState:UIControlStateSelected barMetrics:UIBarMetricsDefault];

    self.rightButton = self.navigationItem.rightBarButtonItem;
    self.navigationItem.rightBarButtonItem = nil;
}

- (void)documentInteractionControllerDidEndPreview:(UIDocumentInteractionController *)controller
{
    UIImage *transparentImage = [UIImage imageNamed:@"transparent.png"];
    [[UIBarButtonItem appearance] setBackgroundImage:transparentImage forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
    [[UIBarButtonItem appearance] setBackgroundImage:transparentImage forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
    [[UIBarButtonItem appearance] setBackgroundImage:transparentImage forState:UIControlStateSelected barMetrics:UIBarMetricsDefault];

    self.navigationItem.rightBarButtonItem = self.rightButton;
}

Its not perfect but its much better than it was. If anyone can figure out how to handle the presenting controller’s rightBarButtonItem I will accept your answer instead.