本文的程式碼實現效果如下：

除了第三個tabbarItem顯示數字，其他的都顯示紅點

程式碼如下：

//tabbar訊息未讀數量
- (void)showUnreadCountViewItemNO:(NSInteger)index unReadCountSum:(NSInteger)unReadCountSum {
    UILabel *bageView = (UILabel*)[self.tabBarController.tabBar subviewWithTag:1000+index];
    if(unReadCountSum){
        if(!bageView){
            bageView = [[UILabel alloc] init];
            bageView.backgroundColor = kDefaultColor;
            bageView.tag = 1000+index;
            [self.tabBarController.tabBar addSubview:bageView];
            if(index == 2){
                bageView.frame=CGRectMake(WIDTH/4/2+WIDTH/4*index+8, 4, 16, 16);
                [CALayer updateControlLayer:bageView.layer radius:8 borderWidth:0 borderColor:nil];
                bageView.textAlignment = NSTextAlignmentCenter;
                bageView.textColor = WHITE_COLOR;
            }else{
                bageView.frame=CGRectMake(WIDTH/4/2+WIDTH/4*index+8, 4, 10, 10);
                [CALayer updateControlLayer:bageView.layer radius:5 borderWidth:0 borderColor:nil];
            }
        }
        if(index == 2){
            NSString *numStr;
            if(unReadCountSum>100){
                numStr = @"99+";
                bageView.font = FONT_SYSTEM_SIZE(10);
            }else{
                numStr = [NSString stringWithFormat:@"%ld", (long)unReadCountSum];
                bageView.font = FONT_SYSTEM_SIZE(12);
            }
            bageView.text = numStr;
            [UIApplication sharedApplication].applicationIconBadgeNumber = unReadCountSum;
        }
    }else{
        if(bageView){
            [bageView removeFromSuperview];
        }
        if(index==2){
            [UIApplication sharedApplication].applicationIconBadgeNumber = unReadCountSum;
        }
    }
}