Podcast/lib/angular/docs/partials/api/ng.directive:ngHide.html

<a href="http://github.com/angular/angular.js/tree/v1.2.0rc1/src/ng/directive/ngShowHide.js#L155" class="view-source btn btn-action"><i class="icon-zoom-in"> </i> View source</a><a href="http://github.com/angular/angular.js/edit/master/src/ng/directive/ngShowHide.js" class="improve-docs btn btn-primary"><i class="icon-edit"> </i> Improve this doc</a><h1><code ng:non-bindable="">ngHide</code>
<div><span class="hint">directive in module <code ng:non-bindable="">ng</code>
</span>
</div>
</h1>
<div><h2 id="Description">Description</h2>
<div class="description"><div class="ng-directive-page ng-directive-nghide-page"><p>The <code>ngHide</code> directive shows and hides the given HTML element conditionally based on the expression
provided to the ngHide attribute. The show and hide mechanism is a achieved by removing and adding
the <code>ng-hide</code> CSS class onto the element. The <code>.ng-hide</code> CSS class is a predefined CSS class present
in AngularJS which sets the display style to none (using an !important flag).</p>
<pre class="prettyprint linenums">
&lt;!-- when $scope.myValue is truthy (element is hidden) --&gt;
&lt;div ng-hide="myValue"&gt;&lt;/div&gt;

&lt;!-- when $scope.myValue is falsy (element is visible) --&gt;
&lt;div ng-hide="myValue" class="ng-hide"&gt;&lt;/div&gt;
</pre>
<p>When the ngHide expression evaluates to true then the .ng-hide CSS class is added to the class attribute
on the element causing it to become hidden. When false, the ng-hide CSS class is removed
from the element causing the element not to appear hidden.</p>
<h4>Why is !important used?</h2>
<p>You may be wondering why !important is used for the .ng-hide CSS class. This is because the <code>.ng-hide</code> selector
can be easily overridden by heavier selectors. For example, something as simple
as changing the display style on a HTML list item would make hidden elements appear visible.
This also becomes a bigger issue when dealing with CSS frameworks.</p>
<p>By using !important, the show and hide behavior will work as expected despite any clash between CSS selector
specificity (when !important isn&#39;t used with any conflicting styles). If a developer chooses to override the
styling to change how to hide an element then it is just a matter of using !important in their own CSS code.</p>
<h5>Overriding .ng-hide</h5>
<p>If you wish to change the hide behavior with ngShow/ngHide then this can be achieved by
restating the styles for the .ng-hide class in CSS:
<pre class="prettyprint linenums">
.ng-hide {
  
<div class="nocode nocode-content" data-popover data-content="Not to worry, this will override the AngularJS default..." data-title="CSS Specificity">display:block!important;</div>

  //this is just another form of hiding an element
  position:absolute;
  top:-9999px;
  left:-9999px;
}
</pre>
<p>Just remember to include the important flag so the CSS override will function.</p>
<h2>A note about animations with ngHide</h4>
<p>Animations in ngShow/ngHide work with the show and hide events that are triggered when the directive expression
is true and false. This system works similar to the animation system present with ngClass, however, the
only difference is that you must also include the !important flag to override the display property so
that you can perform an animation when the element is hidden during the time of the animation.</p>
<pre class="prettyprint linenums">
//
//a working example can be found at the bottom of this page
//
.my-element.ng-hide-add, .my-element.ng-hide-remove {
  transition:0.5s linear all;
  display:block!important;
}

.my-element.ng-hide-add { ... }
.my-element.ng-hide-add.ng-hide-add-active { ... }
.my-element.ng-hide-remove { ... }
.my-element.ng-hide-remove.ng-hide-remove-active { ... }
</pre>
</div></div>
<h2 id="Usage">Usage</h2>
<div class="usage">as attribute<pre class="prettyprint linenums">&lt;ANY ng-hide="{expression}"&gt;
   ...
&lt;/ANY&gt;</pre>
as class<pre class="prettyprint linenums">&lt;ANY class="ng-hide: {expression};"&gt;
   ...
&lt;/ANY&gt;</pre>
<h3 id="Animations">Animations</h3>
<div class="animations"><ul><li>removeClass: .ng-hide - happens after the ngHide expression evaluates to a truthy value and just before the contents are set to hidden</li><li>addClass: .ng-hide - happens after the ngHide expression evaluates to a non truthy value and just before the contents are set to visible</li></ul></div>
<a href="api/ngAnimate.$animate">Click here</a> to learn more about the steps involved in the animation.<h4 id="parameters">Parameters</h4><table class="variables-matrix table table-bordered table-striped"><thead><tr><th>Param</th><th>Type</th><th>Details</th></tr></thead><tbody><tr><td>ngHide</td><td><a href="" class="label type-hint type-hint-expression">expression</a></td><td><div class="ng-directive-page ng-directive-nghide-page"><p>If the <a href="guide/expression">expression</a> is truthy then
the element is shown or hidden respectively.</p>
</div></td></tr></tbody></table></div>
<h2 id="Example">Example</h2>
<div class="example"><div class="ng-directive-page ng-directive-nghide-page"><h4>Source</h2>
<div source-edit="" source-edit-deps="angular.js angular-animate.js" source-edit-html="index.html-92" source-edit-css="animations.css" source-edit-js="" source-edit-json="" source-edit-unit="" source-edit-scenario="scenario.js-93"></div>
<div class="tabbable"><div class="tab-pane" title="index.html">
<pre class="prettyprint linenums" ng-set-text="index.html-92" ng-html-wrap=" angular.js angular-animate.js"></pre>
<script type="text/ng-template" id="index.html-92">
  Click me: <input type="checkbox" ng-model="checked"><br/>
  <div>
    Show:
    <div class="check-element animate-hide" ng-show="checked">
      <span class="icon-thumbs-up"></span> I show up when your checkbox is checked.
    </div>
  </div>
  <div>
    Hide:
    <div class="check-element animate-hide" ng-hide="checked">
      <span class="icon-thumbs-down"></span> I hide when your checkbox is checked.
    </div>
  </div>
</script>
</div>
<div class="tab-pane" title="animations.css">
<pre class="prettyprint linenums" ng-set-text="animations.css"></pre>
<style type="text/css" id="animations.css">
  .animate-hide.ng-hide-add, 
  .animate-hide.ng-hide-remove {
    -webkit-transition:all linear 0.5s;
    -moz-transition:all linear 0.5s;
    -o-transition:all linear 0.5s;
    transition:all linear 0.5s;
    display:block!important;
  }

  .animate-hide.ng-hide-add.ng-hide-add-active,
  .animate-hide.ng-hide-remove {
    line-height:0;
    opacity:0;
    padding:0 10px;
  }

  .animate-hide.ng-hide-add,
  .animate-hide.ng-hide-remove.ng-hide-remove-active {
    line-height:20px;
    opacity:1;
    padding:10px;
    border:1px solid black;
    background:white;
  }

  .check-element {
    padding:10px;
    border:1px solid black;
    background:white;
  }
</style>
</div>
<div class="tab-pane" title="End to end test">
<pre class="prettyprint linenums" ng-set-text="scenario.js-93"></pre>
<script type="text/ng-template" id="scenario.js-93">
   it('should check ng-show / ng-hide', function() {
     expect(element('.doc-example-live .check-element:first:hidden').count()).toEqual(1);
     expect(element('.doc-example-live .check-element:last:visible').count()).toEqual(1);

     input('checked').check();

     expect(element('.doc-example-live .check-element:first:visible').count()).toEqual(1);
     expect(element('.doc-example-live .check-element:last:hidden').count()).toEqual(1);
   });
</script>
</div>
</div><div class="pull-right"> <button class="btn btn-primary" ng-click="animationsOff=true" ng-hide="animationsOff">Animations on</button> <button class="btn btn-primary disabled" ng-click="animationsOff=false" ng-show="animationsOff">Animations off</button></div><h2>Demo</h4>
<div class="well doc-example-live animate-container" ng-class="{'animations-off':animationsOff == true}" ng-embed-app="" ng-set-html="index.html-92" ng-eval-javascript=""></div>
</div></div>
</div>