带有下拉菜单的 Bootstrap-4 按钮选择的值不显示

Question

我使用了bootstrap-4 带有下拉菜单的按钮我有一些问题，该下拉菜单没有显示选定的值？我想知道如何在正确选择值时设置货币名称，我的代码有问题，为此获取一次所有值，您可以理解该问题，请查看snippet

$(".dropdown-menu ").click(function(){

  $(this).parents(".input-group-btn").find('.btn').text($(this).text());
 

});

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" integrity="sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js" integrity="sha384-vFJXuSJphROIrBnz7yo7oB41mKfc8JzQZiCq4NCceLEaO4IHwicKwpJf9c9IpFgh" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js" integrity="sha384-alpBpkh1PFOepccYVYDB4do5UnbKysX5WZXm3XxPqe5iKTfUKjNkCk9SaVuEZflJ" crossorigin="anonymous"></script>
<div class="row">
  <div class="col-lg-6">
    <div class="input-group">
      <div class="input-group-btn">
        <button type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
         Currency
        </button>
        <div class="dropdown-menu">
          <a class="dropdown-item" href="#">USD</a>
          <a class="dropdown-item" href="#">AUS</a>
       
        </div>
      </div>
      <input type="text" class="form-control" aria-label="Text input with dropdown button">
    </div>
  </div>
 
</div>

Answer 1

我解决了我的问题 解决方案 01
按钮像选择框一样工作，我更改了我的script

<script>

            $('.dropdown-menu a').on('click', function(){    
        $('.dropdown-toggle').html($(this).html());    
    })
        </script>

现在它对我有用

<script>

            $('.dropdown-menu a').on('click', function(){    
        $('.dropdown-toggle').html($(this).html());    
    })
        </script>

	$('.dropdown-menu a').on('click', function(){    
    $('.dropdown-toggle').html($(this).html());    
})

Solution-02 脚本

        $(".dropdown-menu a ").click(function(){

  $(this).parents(".input-group-btn").find('.btn').text($(this).text());


});

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" integrity="sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js" integrity="sha384-vFJXuSJphROIrBnz7yo7oB41mKfc8JzQZiCq4NCceLEaO4IHwicKwpJf9c9IpFgh" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js" integrity="sha384-alpBpkh1PFOepccYVYDB4do5UnbKysX5WZXm3XxPqe5iKTfUKjNkCk9SaVuEZflJ" crossorigin="anonymous"></script>
<div class="row">
  <div class="col-lg-6">
    <div class="input-group">
      <div class="input-group-btn">
        <button type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
         Currency
        </button>
        <div class="dropdown-menu">
          <a class="dropdown-item" href="#">USD</a>
          <a class="dropdown-item" href="#">AUS</a>
       
        </div>
      </div>
      <input type="text" class="form-control" aria-label="Text input with dropdown button">
    </div>
  </div>
 
</div>

        $(".dropdown-menu a ").click(function(){

  $(this).parents(".input-group-btn").find('.btn').text($(this).text());


});