UIButton在处于selected的情况下点击的问题

    [button setBackgroundImage:backImage forState:UIControlStateNormal];
    [button setBackgroundImage:backImage forState:UIControlStateHighlighted];
    [button setBackgroundImage:selecetedBackImage forState:UIControlStateSelected | UIControlStateHighlighted];
    [button setBackgroundImage:selecetedBackImage forState:UIControlStateSelected];
    [button setImage:iconImage forState:UIControlStateNormal];
    [button setImage:iconImage forState:UIControlStateHighlighted];
    [button setImage:iconImage forState:UIControlStateSelected|UIControlStateHighlighted];
    [button setTitle:text forState:UIControlStateNormal];
    [button.titleLabel setFont:[UIFont systemFontOfSize:12.0]];

自定义tabbar用button替代tabbaritem遇到了一个问题。就是在选中button的情况下，再次点击button，会变成默认的图片，看起来很不美观。

 查了好久终于看到原来还是state的原因。

UIControlStateSelected | UIControlStateHighlighted

UIControlStateSelected

这俩代表的不同，UIControlStateSelected | UIControlStateHighlighted 是处于selected 的情况下，再次点击高亮的效果。