How can I have a popover come from a tab instead o

问题:

I have a tabbar app, and I want a popover to come from one of the tabs. Is there a good/easy way to do this without changing views?

回答1:

There isn't currently a way to directly (through a supported api call) get the frame of a specific tab bar item. What I do is just show the popup from the left end of the tab bar like this:

CGFloat tabBarHeight = self.tabBarController.tabBar.bounds.size.height;
CGRect rect = CGRectMake(0, 0, tabBarHeight, tabBarHeight);
[popoverController presentPopoverFromRect:rect 
    inView:self.tabBarController.tabBar 
    permittedArrowDirections:UIPopoverArrowDirectionDown animated:YES];

You could try to estimate the position of the tab bar item taking the current orientation into account if you really wanted to and adjust the X coordinate of the rect above.

You could also look through the subviews of the tabbar and find the UITabBarButton object but that's not documented so it's not recommended.