ios 自定义带下划线的tab切换按钮

1. 创建2个tab栏切换的TabBar

#pragma mark -- 创建顶部Tab切换按钮
- (void)createTopTabBarSegment
{
    if(!_segmentLineView)
    {
        _segmentLineView = [[UIView alloc] initWithFrame:CGRectMake((kDEVICEWIDTH - TOPTABBARWIDTH*2 - 35)/2.0, 20+38, TOPTABBARWIDTH, 2)];
        _segmentLineView.backgroundColor = loadColor(@"0093ff");
        [self.view addSubview:_segmentLineView];
    }
    
    ／／多少个tab
    for (NSInteger i = 0; i < _segmentTitleArray.count; i++)
    {
        UIButton * segmentButton = [UIButton buttonWithType:UIButtonTypeCustom];
        segmentButton.frame = CGRectMake((kDEVICEWIDTH - TOPTABBARWIDTH*2 - 35)/2.0 + TOPTABBARWIDTH*i, 20, TOPTABBARWIDTH, 40);
        segmentButton.tag = 9999 + i;
        [segmentButton setTitle:[_segmentTitleArray objectAtIndex:i] forState:UIControlStateNormal];
        [segmentButton setTitle:[_segmentTitleArray objectAtIndex:i] forState:UIControlStateSelected];
        [segmentButton  setTitleColor:TFCOLOR_68758E forState:UIControlStateNormal];
        [segmentButton  setTitleColor:loadColor(@"0093ff")  forState:UIControlStateSelected];
        segmentButton.titleLabel.font = loadFont(18.f);
        [segmentButton addTarget:self action:@selector(didTopTabSelectClick:) forControlEvents:UIControlEventTouchUpInside];
        [self.view addSubview:segmentButton];
        if (i == 0)//默认选中第一个tab
        {
            _selectedTabBtn = segmentButton;
            [segmentButton setSelected:YES];
        }
    }
}

#pragma mark --  顶部tab选择事件
- (void)didTopTabSelectClick:(UIButton*)sender
{
    _segmentLineView.frame = CGRectMake((kDEVICEWIDTH - TOPTABBARWIDTH*2 - 35)/2.0 + TOPTABBARWIDTH * (sender.tag - 9999), 20+38, TOPTABBARWIDTH, 2);
    _selectedTabBtn.selected = !_selectedTabBtn.selected;
    sender.selected = !sender.selected;
    _selectedTabBtn = sender;
    
    if (sender.tag == 9999)
    {
        self.currentSelectedTabIndex = 0;
    }
    else if (sender.tag == 10000)
    {

        self.currentSelectedTabIndex = 1;

}}

//清除顶部的tabBar UI上的数据
- (void)clearTopTabBarSegment
{ //先将顶部的View移除掉，再去添加 
  UIButton *ljBtn = (UIButton*)[self.view viewWithTag:9999];
 if (ljBtn) { [ljBtn removeFromSuperview]; }
 UIButton *ljBtn1 = (UIButton*)[self.view viewWithTag:10000];
 if (ljBtn1) { [ljBtn1 removeFromSuperview]; } 
 if(_segmentLineView) { [_segmentLineView removeFromSuperview]; _segmentLineView = nil; }}

2. 当从第一个页面里面的某一个button切换到第二个tab时，可以这样处理

#pragma mark -- 查看按钮点击
- (void)aroundClicked
{
    CHDebugLog(@"%s",__FUNCTION__);
    
    if (_selectedTabBtn.tag == 9999)
    {
        if ([self respondsToSelector:@selector(didTopTabSelectClick:)])
        {
             UIButton *ljBtn1 = (UIButton*)[self.view viewWithTag:10000];／／将当前页面里面的第二个tab找到传过去
             [self performSelector:@selector(didTopTabSelectClick:) withObject:ljBtn1];
        }
    }
}