AngularJS: ng-show / ng-hide not working with `{{ }}` interpolation
AngularjsNg ShowNg HideAngularjs Problem Overview
I am trying to show / hide some HTML using the ng-show and ng-hide functions provided by AngularJS.
According to the documentation, the respective usage for these functions are as follows:
> ngHide – {expression} - If the expression truthy then the element is shown or hidden respectively. > ngShow – {expression} - If the expression is truthy then the element is shown or hidden respectively.
This works for the following usecase:
<p ng-hide="true">I'm hidden</p>
<p ng-show="true">I'm shown</p>
However, should we use a parameter from an object as the expression then the ng-hide and ng-show are given the correct true/false value but the values are not treated as a boolean so always return false:
Source
<p ng-hide="{{foo.bar}}">I could be shown, or I could be hidden</p>
<p ng-show="{{foo.bar}}">I could be shown, or I could be hidden</p>
Result
<p ng-hide="true">I should be hidden but I'm actually shown</p>
<p ng-show="true">I should be shown but I'm actually hidden</p>
This is either a bug or I am not doing this correctly.
I cannot find any relative information on referencing object parameters as expressions so I was hoping anyone with a better understanding of AngularJS might be able to help me out?
Angularjs Solutions
Solution 1 - Angularjs
The foo.bar reference should not contain the braces:
<p ng-hide="foo.bar">I could be shown, or I could be hidden</p>
<p ng-show="foo.bar">I could be shown, or I could be hidden</p>
Angular expressions need to be within the curly-brace bindings, where as Angular directives do not.
See also Understanding Angular Templates.
Solution 2 - Angularjs
You can't use {{}} when using angular directives for binding with ng-model but for binding non-angular attributes you would have to use {{}}..
Eg:
ng-show="my-model"
title = "{{my-model}}"
Solution 3 - Angularjs
Try wrapping expression with:
$scope.$apply(function() {
$scope.foo.bar=true;
})
Solution 4 - Angularjs
Since ng-show is an angular attribute i think, we don't need to put the evaluation flower brackets ({{}})..
For attributes like class we need to encapsulate the variables with evaluation flower brackets ({{}}).
Solution 5 - Angularjs
<script src="http://code.angularjs.org/1.2.0-rc.2/angular.js"></script>
<script type="text/javascript">
function controller($scope) {
$scope.data = {
show: true,
hide: false
};
}
</script>
<div ng-controller="controller">
<div ng-show="data.show"> If true the show otherwise hide. </div>
<div ng-hide="!(data.hide)"> If true the show otherwise hide.</div>
</div>
Solution 6 - Angularjs
remove {{}} braces around foo.bar because angular expressions cannot be used in angular directives.
For More: https://docs.angularjs.org/api/ng/directive/ngShow
example
<body ng-app="changeExample">
<div ng-controller="ExampleController">
<p ng-show="foo.bar">I could be shown, or I could be hidden</p>
<p ng-hide="foo.bar">I could be shown, or I could be hidden</p>
</div>
</body>
<script>
angular.module('changeExample', [])
.controller('ExampleController', ['$scope', function($scope) {
$scope.foo ={};
$scope.foo.bar = true;
}]);
</script>
Solution 7 - Angularjs
If you want to show/hide an element based on the status of one {{expression}} you can use ng-switch:
<p ng-switch="foo.bar">I could be shown, or I could be hidden</p>
The paragraph will be displayed when foo.bar is true, hidden when false.