自定义的UITabbar上面的按钮的x坐标的计算方法

 for (int i = ; i < 4; i++) {//4是按钮的个数

        NSString *backImage = backgroud[i];

        NSString *heightImage = heightBackground[i];

        UIButton *button = [UIFactory createButton:backImage highlighted:heightImage];

        button.showsTouchWhenHighlighted = YES;

        button.frame = CGRectMake(/  * i + , (-)/, , );//4是按钮的个数;25是自己不断修改得来的.

        [button addTarget:self action:@selector(selectedTab:) forControlEvents:UIControlEventTouchUpInside];

        [_tabbarView addSubview:button];

    }

效果如图：