网上大多的自己定义TabBar都是继承View的，项目中要用到path+Tabbat这种话(path用的MMDrawerController这个框架)，继承View的Tabbar是无法满足条件的（不是一个容器）。以下就介绍下自己写的一个自己定义TabBar。
和系统自带的写法差点儿相同，先看下原生的写法例如以下：
首先在.h中自己定义一个UITabBarController* tabBarViewController; 接着在.m中来做实现，
tabBarViewController = [[UITabBarController alloc]init];
FirstViewController* first = [[FirstViewController alloc]init];
UINavigationController * navOne = [[UINavigationController alloc] initWithRootViewController:first ];
[navOne setNavigationBarHidden:TRUE];
SecondViewController* second = [[SecondViewController alloc]init];
UINavigationController * navtwo = [[UINavigationController alloc] initWithRootViewController:second ];
[navtwo setNavigationBarHidden:TRUE];
ViewController3 *vc3 = [[ViewController3 alloc] init];
UINavigationController * nav3 = [[UINavigationController alloc] initWithRootViewController:vc3 ];
[nav3 setNavigationBarHidden:TRUE];
ViewController5 *vc5 = [[ViewController5 alloc] init];
UINavigationController * nav5 = [[UINavigationController alloc] initWithRootViewController:vc5 ];
[nav5 setNavigationBarHidden:TRUE];
tabBarViewController.viewControllers = [NSArray arrayWithObjects:navOne, navtwo,nav3,nav5, nil];
[first release];
[second release];
[vc3 release];
[vc5 release];
UITabBar *tabBar = tabBarViewController.tabBar;
UITabBarItem *tabBarItem1 = [tabBar.items objectAtIndex:0];
UITabBarItem *tabBarItem2 = [tabBar.items objectAtIndex:1];
UITabBarItem *tabBarItem3 = [tabBar.items objectAtIndex:2];
UITabBarItem *tabBarItem4 = [tabBar.items objectAtIndex:3];
tabBarItem1.title = @"消息";
tabBarItem2.title = @"应用";
tabBarItem3.title = @"通讯录";
tabBarItem4.title = @"我";
[tabBarItem1 setFinishedSelectedImage:[UIImage imageNamed:@"home_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"home.png"]];
[tabBarItem2 setFinishedSelectedImage:[UIImage imageNamed:@"maps_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"maps.png"]];
[tabBarItem3 setFinishedSelectedImage:[UIImage imageNamed:@"myplan_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"myplan.png"]];
[tabBarItem4 setFinishedSelectedImage:[UIImage imageNamed:@"settings_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"settings.png"]];
UIImage* tabBarBackground = [UIImage imageNamed:@"tabbar.png"];
[[UITabBar appearance] setBackgroundImage:tabBarBackground];
[[UITabBar appearance] setSelectionIndicatorImage:[UIImage imageNamed:@"tabbar_selected.png"]];
[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
[UIColor whiteColor], UITextAttributeTextColor,
nil] forState:UIControlStateNormal];
UIColor *titleHighlightedColor = [UIColor greenColor];
[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
titleHighlightedColor, UITextAttributeTextColor,
nil] forState:UIControlStateSelected];
以下来看下自己定义的方法，也是在.h文件里定义
UITabBarController* tabBarViewController;
在定义一个long preSelect变量，这个变量用来推断点击是哪个selectedIndex。
在.m中的详细实现例如以下：
NSMutableArray *arrController = [[NSMutableArray alloc]init];
//信息
MessageViewController *messageVC = [[MessageViewController alloc]initWithNibName:@"MessageViewController" bundle:nil];
UINavigationController * navMessage = [[UINavigationController alloc] initWithRootViewController:messageVC ];
[messageVC release];
[navMessage setNavigationBarHidden:TRUE];
[arrController addObject:navMessage];
[navMessage release];
//应用
AppsViewController *appsVC = [[AppsViewController alloc]initWithNibName:@"AppsViewController" bundle:nil];
UINavigationController *navApps = [[UINavigationController alloc] initWithRootViewController:appsVC];
[appsVC release];
[navApps setNavigationBarHidden:TRUE];
[arrController addObject:navApps];
[navApps release];
//通讯录
AddressViewController *addressVC = [[AddressViewController alloc]initWithNibName:@"AddressViewController" bundle:nil];
UINavigationController *navAddress = [[UINavigationController alloc] initWithRootViewController:addressVC];
[addressVC release];
[navAddress setNavigationBarHidden:TRUE];
[arrController addObject:navAddress];
[navAddress release];
//我
MeViewController *meVC = [[MeViewController alloc]initWithNibName:@"MeViewController" bundle:nil];
UINavigationController *navMe = [[UINavigationController alloc] initWithRootViewController:meVC];
[meVC release];
[navMe setNavigationBarHidden:TRUE];
[arrController addObject:navMe];
[navMe release];
tabBarViewController=[[UITabBarController alloc] init];
tabBarViewController.viewControllers=arrController;
[arrController release];
preSelect = 1;
for (int i = 0; i<4; i++) {
NSString *nalString = [NSString stringWithFormat:@"tabbar_unselecte%d.png", i+1];
NSString *highString = [NSString stringWithFormat:@"tabbar_selected%d.png", i+1];
UIImage *nalImage = [UIImage imageNamed:nalString];
UIImage *highImage = [UIImage imageNamed:highString];
UIButton *tabbarBtn = [UIButton buttonWithType:UIButtonTypeCustom];
tabbarBtn.frame = CGRectMake(i*(320/4), 0, (320/4), 46);
[tabbarBtn addTarget:self action:@selector(tabbarBtnPress:) forControlEvents:UIControlEventTouchUpInside];
[tabbarBtn setBackgroundImage:nalImage forState:UIControlStateNormal];
[tabbarBtn setBackgroundImage:highImage forState:UIControlStateSelected];
tabbarBtn.tag = 100+i;
[tabBarViewController.tabBar addSubview:tabbarBtn];
if (i == 1) {
tabbarBtn.selected = YES;
tabBarViewController.selectedIndex=1;
}
}主要是思路就是自己定义UITabBarController的tabBar属性，在它上面addSubview。因为加的UIButton，如今就要实现点击
方法来切换。
方法例如以下：
-(void)tabbarBtnPress:(UIButton *)tabbarBtn
{
if (preSelect != tabbarBtn.tag -100 ) {
UIButton *prvBtn = (UIButton *)[tabbarBtn.superview viewWithTag:preSelect+100];
prvBtn.selected = NO;
tabBarViewController.selectedIndex = preSelect = tabbarBtn.tag-100;
UIButton *button = (UIButton *)[tabbarBtn.superview viewWithTag:tabbarBtn.tag];
button.selected = YES;
}
}到此就完毕了。有什么不正确地方请大家指出来。
5.29日补充：
上面写的是默认是选中第2个tabbar，选中第一个时。仅仅须要改动preSelect =0;和
if(i==0)
{
tabbarBtn.selected =YES;
self.selectedIndex=0;
}
假设想把这个独立出来，仅仅须要定义一个继承UITabBarController的类。
假设想用自己定义的背景也能够 。能够把系统的给隐藏(self.tabBar.hidden =YES;)，自己定义一个View,加到tabbar上。[self.view addSubview:xxxx]; ，其他还是用上面的方法。
6.3：
发现了一个问题。VC的nav不显示，找了下原因，发现 tabbarController.viewControllers 中设置是VC数组，不是nav数组。