angularjs 实现带查找筛选功能的select下拉框实例

一.背景

对于select的下拉列表，像国家选择这样的功能，全世界那么多国家，一直拉滚动条多辛苦，眼睛也要盯着找，累！so，为优化用户体验，带查找功能的下拉框是非常非常有必要的。都知道jquery里有这样的插件，但我们用的是Angularjs,更希望用双向绑定，指令的方式优雅地解决这个问题。

分析：

二.具体实现

1.代码部分

1.1 js代码(请引先引入jquery，不然会报错)

/**
 * 带筛选功能的下拉框
 * 使用方法 <select ngc-select-search name="select1" ng-options="">
 * 说明[ select 一定要有name,ng-options 属性]
 */
 .directive('ngcSelectSearch', function($animate, $compile, $parse) {

  function parseOptions(optionsExp, element, scope) {
   // ngOptions里的正则
   var NG_OPTIONS_REGEXP = /^\s*([\s\S]+?)(?:\s+as\s+([\s\S]+?))?(?:\s+group\s+by\s+([\s\S]+?))?(?:\s+disable\s+when\s+([\s\S]+?))?\s+for\s+(?:([\$\w][\$\w]*)|(?:\(\s*([\$\w][\$\w]*)\s*,\s*([\$\w][\$\w]*)\s*\)))\s+in\s+([\s\S]+?)(?:\s+track\s+by\s+([\s\S]+?))?$/;

   var match = optionsExp.match(NG_OPTIONS_REGEXP);
   if (!(match)) {
    console.log('ng-options 表达式有误')
   }
   var valueName = match[5] || match[7];
   var keyName = match[6];
   var displayFn = $parse(match[2]);
   var keyFn = $parse(match[1]);
   var valuesFn = $parse(match[8]);

   var labelArray = [],
    idArray = [],
    optionValues = [];
   scope.$watch(match[8], function(newValue, oldValue) {
    if (newValue && newValue.length > 0) {
     optionValues = valuesFn(scope) || [];
     labelArray = [];
     idArray = []
     for (var index = 0, l = optionValues.length; index < l; index++) {
      var it = optionValues[index];
      if (match[2] && match[1]) {
       var localIt = {};
       localIt[valueName] = it;
       var label = displayFn(scope, localIt);
       var dataId = keyFn(scope, localIt);
       labelArray.push(label);
       idArray.push(dataId);
      }
     }

     scope.options = {
      'optionValues': optionValues,
      'labelArray': labelArray,
      'idArray': idArray
     }
    }
   });
  }
  return {
   restrict: 'A',
   require: ['ngModel'],
   priority: 100,
   replace: false,
   scope: true,
   template: '<div class="chose-container">' +
    '<div class="chose-single"><span class="j-view"></span><i class="glyphicon glyphicon-remove"></i></div>' +
    '<div class="chose-drop chose-hide j-drop">' +
    '<div class="chose-search">' +
    '<input class="j-key" type="text" autocomplete="off">' +
    '</div>' +
    '<ul class="chose-result">' +
    // '<li ng-repeat="'+repeatTempl+'" data-id="'+keyTempl+'" >{{'+ valueTempl+'}}</li>'+
    '</ul>' +
    '</div>' +
    '</div>',
   link: {
    pre: function selectSearchPreLink(scope, element, attr, ctrls) {

     var tmplNode = $(this.template).first();

     var modelName = attr.ngModel,
      name = attr.name? attr.name:('def'+Date.now());
     tmplNode.attr('id', name + '_chosecontianer');

     $animate.enter(tmplNode, element.parent(), element);
    },
    post: function selectSearchPostLink(scope, element, attr, ctrls) {
     var choseNode = element.next(); //$('#'+attr.name +'_chosecontianer');
     choseNode.addClass(attr.class);
     element.addClass('chose-hide');
     // 当前选中项
     var ngModelCtrl = ctrls[0];
     if (!ngModelCtrl || !attr.name) return;

     parseOptions(attr.ngOptions, element, scope);
     var rs = {};

     function setView() {
      var currentKey = ngModelCtrl.$modelValue;
      if (isNaN(currentKey) || !currentKey) {
       currentKey = '';
       choseNode.find('.j-view:first').text('请选择');
       choseNode.find('i').addClass('chose-hide');
      }
      if ((currentKey + '').length > 0) {
       for (var i = 0, l = rs.idArray.length; i < l; i++) {
        if (rs.idArray[i] == currentKey) {
         choseNode.find('.j-view:first').text(rs.labelArray[i]);
         choseNode.find('i').removeClass('chose-hide');
         break;
        }
       }
      }
     }

     function setViewAndData() {
      if (!scope.options) {
       return;
      }
      rs = scope.options;
      setView();
     }
     scope.$watchCollection('options', setViewAndData);
     scope.$watch(attr.ngModel, setView);

     function getListNodes(value) {
      var nodes = [];
      value = $.trim(value);
      for (var i = 0, l = rs.labelArray.length; i < l; i++) {
       if (rs.labelArray[i].indexOf(value) > -1) {
        nodes.push($('<li>').data('id', rs.idArray[i]).text(rs.labelArray[i]))
       }
      }
      return nodes;

     }
     choseNode.on('keyup', '.j-key', function() {
      // 搜索输入框keyup，重新筛选列表
      var value = $(this).val();
      choseNode.find('ul:first').empty().append(getListNodes(value));
      return false;
     }).on('click', function() {
      choseNode.find('.j-drop').removeClass('chose-hide');
      if (choseNode.find('.j-view:first').text() != '请选择') {
       choseNode.find('i').removeClass('chose-hide');
      }
      choseNode.find('ul:first').empty().append(getListNodes(choseNode.find('.j-key').val()));
      return false;
     }).on('click', 'ul>li', function() {
      var _this = $(this);
      ngModelCtrl.$setViewValue(_this.data('id'));
      ngModelCtrl.$render();
      choseNode.find('.j-drop').addClass('chose-hide');
      return false;

     }).on('click', 'i', function() {
      ngModelCtrl.$setViewValue('');
      ngModelCtrl.$render();
      choseNode.find('.j-view:first').text('请选择');
      return false;

     });
     $(document).on("click", function() {
      $('.j-drop').addClass('chose-hide');
      choseNode.find('i').addClass('chose-hide');
      return false;
     });

    }
   }
  };
 })

1.2 css代码(用less写的，以下是编译后的)

.chose-hide {
 position: absolute!important;
 top: -999em !important;
}
.chose-container {
 border: none!important;
 float: left;
 margin-right: 40px;
 padding: 0!important;
 position: relative;
}
.chose-container .chose-single {
 padding: 6px 12px;
 color: #333;
 width: 100%;
 border: 1px solid #eee;
 display: inline-block;
 height: 30px;
}
.chose-container .chose-single::after {
 content: '';
 position: absolute;
 border-width: 6px 3px;
 border-style: solid;
 /* border-top-color: transparent; */
 border-left-color: transparent;
 border-right-color: transparent;
 border-bottom-color: transparent;
 right: 8px;
 top: 12px;
}
.chose-container .chose-single i {
 width: 12px;
 float: right;
 right: 8px;
 font-size: 12px;
 height: 12px;
 background-color: #eee;
}
.chose-container .chose-drop {
 width: 195px;
 position: absolute;
 border: 1px solid #eee;
 z-index: 1000;
 background-color: #fff;
}
.chose-container .chose-search input[type='text'] {
 margin: 0;
 padding-left: 12px;
 width: 100%;
 height: 30px;
 border: 1px solid #ccc;
 float: none;
}
.chose-container .chose-result {
 max-height: 370px;
 overflow-y: scroll;
 overflow-x: hidden;
}
.chose-container .chose-result li {
 padding: 5px 12px;
 list-style-type: none;
}
.chose-container .chose-result li:hover {
 background-color: #e1e2e7;
}

1.3 使用及效果

<select ngc-select-search class="common-select" ng-model="aa.b" ng-options="obj.countryId as obj.countryCnName for obj in vm.countries" name="country">
 <option value="">请选择</option>
</select>

2.详细说明

程序中的关键点是parseOptions函数，即前面分析里的问题1。parseOptions是参考ng-options的源码实现的，原来是想返回一个对象，这个对象里包含了数据源，但是在调试时，发现post函数中该函数返回对象里的数据为空，watch不到，所以改为用scope.options来存数据。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。