MainTabBarController.h
UITabBarItem *item = [self.tabBar.items objectAtIndex:index];
[item setTitle:title];
if (index==2) {
item.imageInsets=UIEdgeInsetsMake(-14, 0, 14, 0);
}
设置tabBar中间的按钮比较大的发布
原文：http://www.cnblogs.com/tufei7/p/7653289.html
