md-autocomplete使用自动提示隐藏固定导航栏

Question

我有这个codepen，我创建了一个导航栏，它固定在顶部。当我向下滚动并搜索某些内容时，导航栏会在显示自动完成结果时消失。

这是HTML代码：

<div ng-controller="DemoCtrl as ctrl" layout="column" ng-cloak="" class="autocompletedemoBasicUsage" ng-app="MyApp">
  <md-toolbar class="md-whiteframe-z1 header_navbar" layout="column"
                style="background-color:#027cd8; min-height:100px; padding-left:1%; padding-right:1.25%; box-shadow:none; position: fixed  !important">
  <md-content class="md-padding">
    <form ng-submit="$event.preventDefault()">
      <p>Use <code>md-autocomplete</code> to search for matches from local or remote data sources.</p>
      <md-autocomplete ng-disabled="ctrl.isDisabled" md-no-cache="ctrl.noCache" md-selected-item="ctrl.selectedItem" md-search-text-change="ctrl.searchTextChange(ctrl.searchText)" md-search-text="ctrl.searchText" md-selected-item-change="ctrl.selectedItemChange(item)" md-items="item in ctrl.querySearch(ctrl.searchText)" md-item-text="item.display" md-min-length="0" placeholder="What is your favorite US state?">
        <md-item-template>
          <span md-highlight-text="ctrl.searchText" md-highlight-flags="^i">{{item.display}}</span>
        </md-item-template>
        <md-not-found>
          No states matching "{{ctrl.searchText}}" were found.
          <a ng-click="ctrl.newState(ctrl.searchText)">Create a new one!</a>
        </md-not-found>
      </md-autocomplete>
    </form>
  </md-content>
    </md-toolbar>
  <div style="background-color:#027cd8; height:500px"></div>
</div>

JS代码：

(function () {
  'use strict';
  angular
      .module('MyApp')
      .controller('DemoCtrl', DemoCtrl);

  function DemoCtrl ($timeout, $q, $log) {
    var self = this;

    self.simulateQuery = false;
    self.isDisabled    = false;

    // list of `state` value/display objects
    self.states        = loadAll();
    self.querySearch   = querySearch;
    self.selectedItemChange = selectedItemChange;
    self.searchTextChange   = searchTextChange;

    self.newState = newState;

    function newState(state) {
      alert("Sorry! You'll need to create a Constituion for " + state + " first!");
    }

    // ******************************
    // Internal methods
    // ******************************

    /**
     * Search for states... use $timeout to simulate
     * remote dataservice call.
     */
    function querySearch (query) {
      var results = query ? self.states.filter( createFilterFor(query) ) : self.states,
          deferred;
      if (self.simulateQuery) {
        deferred = $q.defer();
        $timeout(function () { deferred.resolve( results ); }, Math.random() * 1000, false);
        return deferred.promise;
      } else {
        return results;
      }
    }

    function searchTextChange(text) {
      $log.info('Text changed to ' + text);
    }

    function selectedItemChange(item) {
      $log.info('Item changed to ' + JSON.stringify(item));
    }

    /**
     * Build `states` list of key/value pairs
     */
    function loadAll() {
      var allStates = 'Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware,\
              Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana,\
              Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana,\
              Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina,\
              North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina,\
              South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia,\
              Wisconsin, Wyoming';

      return allStates.split(/, +/g).map( function (state) {
        return {
          value: state.toLowerCase(),
          display: state
        };
      });
    }

    /**
     * Create filter function for a query string
     */
    function createFilterFor(query) {
      var lowercaseQuery = angular.lowercase(query);

      return function filterFn(state) {
        return (state.value.indexOf(lowercaseQuery) === 0);
      };

    }
  }
})();