rightBarButtonItem info button, no space to the right

问题

I have a UIViewController set up to display an info-button on the right in its UINavigationItem like this:

UIButton *infoButton = [UIButton buttonWithType:UIButtonTypeInfoLight];
[infoButton addTarget:self action:@selector(toggleAboutView) forControlEvents:UIControlEventTouchUpInside]; 
self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithCustomView:infoButton] autorelease];

That works perfectly, but the only problem is that I'm left with little to no space to the right of the button, which looks pretty ugly:

Is there any way for the button to move about 5 px out from the right side?

Thanks.

回答1:

infoButton.contentEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 10);

回答2:

Try setting infoButton.contentEdgeInsets (or imageEdgeInsets); something like

infoButton.contentEdgeInsets = (UIEdgeInsets){.right=10};

I'm not sure if it works for "system" buttons, but it might.

If that doesn't work, the easiest way is probably to stick it inside a UIView.

EDIT: Presumably the toolbar calls [customView sizeThatFits:blah] to find out how big the view "wants to be". The above code is supposed to mean "add a 10-pixel right edge inset", which for a normal (custom) button also makes the size bigger by 10 pixels.

It seems like UIButton returns a fixed size for the standard info button, ignoring any insets. Your code "works" by affecting the contentRectForBounds: and imageRectForContentRect: methods, which changes where the icon is drawn, but does not actually change the size of the button. I suspect that the icon is drawing outside the button, which may mean that the "touchable" rect is wrong (but toolbars seem to increase the touch rects for normal UIBarButtonItems, so maybe it doesn't matter).

来源：https://stackoverflow.com/questions/3692057/rightbarbuttonitem-info-button-no-space-to-the-right