UITabBar不显示项目的标题

Question

我使用的是UITabBar，但它没有显示项目的标题。我做错了什么？

这是我正在使用的示例：

    UITabBar *menu = [[UITabBar alloc] initWithFrame:CGRectMake(0, 480 - 100, 320, 100)];

    NSMutableArray *items = [[NSMutableArray alloc] init];
    UITabBarItem *item = [[UITabBarItem alloc] initWithTabBarSystemItem:UITabBarSystemItemRecents tag:0];
    [items addObject:item];
    [item release];
    item = [[UITabBarItem alloc] initWithTitle:@"item 1" image:[UIImage imageNamed:@"test1.png"] tag:1];
    [items addObject:item]; 
    [item release];
    item = [[UITabBarItem alloc] initWithTitle:@"item 2" image:[UIImage imageNamed:@"test2.png"] tag:2];
    [items addObject:item];
    [item release];
    item = [[UITabBarItem alloc] initWithTitle:@"item 3" image:[UIImage imageNamed:@"test3.png"] tag:2];
    [items addObject:item];
    [item release];
    item = [[UITabBarItem alloc] initWithTitle:@"item 4" image:[UIImage imageNamed:@"test4.png"] tag:2];
    [items addObject:item];
    [item release];
    item = [[UITabBarItem alloc] initWithTitle:@"item 5" image:[UIImage imageNamed:@"test5.png"] tag:2];
    [items addObject:item];
    [item release];
    item = [[UITabBarItem alloc] initWithTitle:@"item 6" image:[UIImage imageNamed:@"test6.png"] tag:3];
    [items addObject:item];
    [item release];

    [menu setItems:items animated:false];
    [[self view] addSubview:menu];

    [menu release];