【iPhone代码片段之八】如何自定义Tab Bar Button .
核心代码如下：
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{ CGRect frame = [[UIScreen mainScreen] bounds]; //NSLog(@"x=%.2f,y=%.2f,width=%.2f,height=%.2f",frame.origin.x,frame.origin.y,frame.size.width,frame.size.height); self.window = [[UIWindow alloc] initWithFrame:frame]; [[NSBundle mainBundle]loadNibNamed:@"TabBarController" owner:self options:nil]; //[self.window addSubview:tabBarController.view]; self.window.rootViewController = self.tabBarController; //添加中间的TabBarButton [self addCenternTabBarButton]; self.window.backgroundColor = [UIColor whiteColor]; [self.window makeKeyAndVisible]; return YES;}-(void)addCenternTabBarButton{ //NSLog(@"addCenternTabBarButton"); //创建一个自定义button UIButton *centerButton = [UIButton buttonWithType:UIButtonTypeCustom]; //初始化button的背景图片 UIImage *centerButtonImg = [UIImage imageNamed:@"centerTabBarItem.png"]; //设置button的frame centerButton.frame = CGRectMake(0, 0, centerButtonImg.size.width, centerButtonImg.size.height); //设置button的背景图片 [centerButton setBackgroundImage:centerButtonImg forState:UIControlStateNormal]; //设置button的action [centerButton addTarget:self action:nil forControlEvents:UIControlEventTouchUpInside]; CGFloat imageHeight = centerButtonImg.size.height; CGFloat barHeight = self.tabBarController.tabBar.frame.size.height; //NSLog(@"imageHeight=%2.f,barHeight=%.2f",imageHeight,barHeight); CGFloat delta = imageHeight-barHeight; //NSLog(@"delta=%.2f",delta); //设置centerButton的中心位置 if(delta<=0){//如果图片高度小于等于TabBar高度 centerButton.center = self.tabBarController.tabBar.center; }else{//如果图片高度大于TabBar高度 CGPoint center = self.tabBarController.tabBar.center; center.y = center.y - delta/2.0; centerButton.center = center; } //将centerButton加入到tabBarController中 [self.tabBarController.view addSubview:centerButton];}