UITabBar

UITabBar即选项卡，使用它比较简单，主要是创建UITabBarItem，然后添加到UITabBar的items里。

1、UITabBar的创建

UITabBar *tabBar = [[UITabBaralloc]initWithFrame:CGRectMake(0,420,
320,60)];
2、创建UITabBarItem
有两种方法：
initWithTabBarSystemItem、initWithTitle
这里用initWithTabBarSystemItem作演示
UITabBarItem *tabBarItem01 = [[UITabBarItemalloc]initWithTabBarSystemItem:UITabBarSystemItemDownloadstag:1];
  UITabBarItem *tabBarItem02 = [[UITabBarItemalloc]initWithTabBarSystemItem:UITabBarSystemItemHistorytag:2];
    UITabBarItem *tabBarItem03 = [[UITabBarItemalloc]initWithTabBarSystemItem:UITabBarSystemItemContactstag:3];
   UITabBarItem *tabBarItem04 = [[UITabBarItemalloc]initWithTabBarSystemItem:UITabBarSystemItemMoretag:4];
系统的UITabBarItem的样式主要有以下几种：

typedef NS_ENUM(NSInteger, UITabBarSystemItem) {
    UITabBarSystemItemMore,
    UITabBarSystemItemFavorites,
    UITabBarSystemItemFeatured,
    UITabBarSystemItemTopRated,
    UITabBarSystemItemRecents,
    UITabBarSystemItemContacts,
    UITabBarSystemItemHistory,
    UITabBarSystemItemBookmarks,
    UITabBarSystemItemSearch,
    UITabBarSystemItemDownloads,
    UITabBarSystemItemMostRecent,
    UITabBarSystemItemMostViewed,
};
3、将UITabBarItems添加

NSMutableArray * tabBarItemArray = [NSMutableArrayarrayWithObjects:tabBarItem01,tabBarItem02,tabBarItem03,tabBarItem04,tabBarItem05,tabBarItem06,nil];
    [tabBar setItems:tabBarItemArrayanimated:YES];
4、设置UITabBar的属性

tabBar.tintColor = [UIColorredColor];
5、添加delegate，并实现delegate的方法

tabBar.delegate =self;

- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item
{
    NSInteger tag = item.tag;
    NSString * tagString = [NSStringstringWithFormat:@"您选择了%d个tabBarItem",tag];
    UIAlertView * alertView = [[UIAlertViewalloc]initWithTitle:@"选择了tabBarItem"message:tagString
delegate:selfcancelButtonTitle:@"取消"otherButtonTitles:@"确定",nil];
    [alertView show];
    NSLog(@"您选择的tag是：%d",tag);
}
详细demo见：https://github.com/tingxuan/TXUITabBarDemo