自定义Tabbar方法—

方法一    覆盖式

原理：在Tabbar上放button，让button覆盖掉tabbaritem，再给button添加事件，需要注意的地方是button的坐标

代码如下：

头文件

#import <UIKit/UIKit.h>

@interface BaseTabBarController :UITabBarController

-(void) addCenterButtonWithImage:(UIImage*)buttonImage

                  highlightImage:(UIImage*)highlightImage;

- (void)addLeftButtonWithImage:(UIImage *)buttonImage

                highlightImage:(UIImage *)highlightImage;

- (void)addRightButtonWithImage:(UIImage *)buttonImage

                 highlightImage:(UIImage *)hightlightImage;

@end

.m文件

#import "BaseTabBarController.h"

#define kBtnLeftTag     0

#define kBtnRightTag    2

#define kBtnCenterTag   1

constint width =100.0f;

constfloat centerBtnWidth =67.0f;

constfloat centerBtnHeight =66.0f;

constfloat btnWidth =127.0f;

constfloat btnHeight =49.0f;

@interface BaseTabBarController ()

@end

@implementation BaseTabBarController

- (void)viewDidLoad

{

    [superviewDidLoad];

    self.tabBar.backgroundColor = [UIColorbrownColor];

    [self.tabBarsetBackgroundImage:[UIImageimageNamed:@"tabbarBackground.png"]];

}

-(void) addCenterButtonWithImage:(UIImage*)buttonImage highlightImage:(UIImage*)highlightImage

{

    UIButton* button = [UIButtonbuttonWithType:UIButtonTypeCustom];

    button.tag =kBtnCenterTag;

    button.autoresizingMask =UIViewAutoresizingFlexibleRightMargin |UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleBottomMargin |UIViewAutoresizingFlexibleTopMargin;

    button.frame =CGRectMake(0.0,0.0, buttonImage.size.width, buttonImage.size.height);

    [button setBackgroundImage:buttonImageforState:UIControlStateNormal];

    [button setBackgroundImage:highlightImageforState:UIControlStateHighlighted];

    [button addTarget:selfaction:@selector(didSelectedTabBaritem:)forControlEvents:UIControlEventTouchUpInside];

    

   CGFloat heightDifference = buttonImage.size.height -self.tabBar.frame.size.height;

   if (heightDifference <0)

        button.center =self.tabBar.center;

   else

    {

       CGPoint center =self.tabBar.center;

        center.y = center.y - heightDifference/2.0;

        button.center = center;

    }

    

    [self.viewaddSubview:button];

}

- (void)addLeftButtonWithImage:(UIImage *)buttonImage

                highlightImage:(UIImage *)highlightImage{

    

    UIButton* button = [UIButtonbuttonWithType:UIButtonTypeCustom];

    button.tag =kBtnLeftTag;

    [button addTarget:selfaction:@selector(didSelectedTabBaritem:)forControlEvents:UIControlEventTouchUpInside];

    button.autoresizingMask =UIViewAutoresizingFlexibleRightMargin |UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleBottomMargin |UIViewAutoresizingFlexibleTopMargin;

   float leftBtn_x =0.0f;

   float leftBtn_y =self.tabBar.frame.origin.y;

    button.frame =CGRectMake(leftBtn_x, leftBtn_y,btnWidth,btnHeight);

    [button setBackgroundImage:buttonImageforState:UIControlStateNormal];

    [button setBackgroundImage:highlightImageforState:UIControlStateHighlighted];

    [self.viewaddSubview:button];

}

- (void)addRightButtonWithImage:(UIImage *)buttonImage

                 highlightImage:(UIImage *)highlightImage{

    

    UIButton* button = [UIButtonbuttonWithType:UIButtonTypeCustom];

    button.tag =kBtnRightTag;

    [button addTarget:selfaction:@selector(didSelectedTabBaritem:)forControlEvents:UIControlEventTouchUpInside];

    button.autoresizingMask =UIViewAutoresizingFlexibleRightMargin |UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleBottomMargin |UIViewAutoresizingFlexibleTopMargin;

   float leftBtn_x =self.tabBar.frame.size.width -btnWidth;

   float leftBtn_y =self.tabBar.frame.origin.y;

    button.frame =CGRectMake(leftBtn_x, leftBtn_y,btnWidth,btnHeight);

    [button setBackgroundImage:buttonImageforState:UIControlStateNormal];

    [button setBackgroundImage:highlightImageforState:UIControlStateHighlighted];

    

    [self.viewaddSubview:button];

    

}

- (void)didSelectedTabBaritem:(UIButton *)btn{

    self.selectedIndex = btn.tag;

}

适用于较少的Tabbaritem且中间突出的，效果图