how to change icon in button on click with Angular Js - angularjs

Question

I have the following code:
<md-button class="md-icon-button" aria-label="Favorite" hide-gt-sm ng-click="openLeftMenu()">
<md-icon><i class="material-icons">menu</i></md-icon>
</md-button>
As you can see, inside md-button tag I have md-icon which contains an i element. I want to change the i tag when I click the button. This icon should change back when I click it again. Simply, I want a toggle effect with two icons and I want to achieve this using Angularjs.

Answer 1

You can use ng-switch, like with password redaction:
<md-button ng-switch="vm.isPasswordVisible" ng-click="vm.isPasswordVisible=!vm.isPasswordVisible" ng-class="md-icon-button">
<md-icon ng-switch-when="false" md-font-library="material-icons"> visibility_off </md-icon>
<md-icon ng-switch-when="true" md-font-library="material-icons"> visibility </md-icon>
</md-button>

Answer 2

You can use the ng-class directive
CODE
<md-button class="md-icon-button" aria-label="Favorite" hide-gt-sm ng-click="toggleButton()">
<md-icon><i ng-class="{'material-icons' : toggle, 'material-icons2' : !toggle}">menu</i></md-icon>
</md-button>
CONTROLLER
$scope.toggleButton = function(){
$scope.toggle = !$scope.toggle;
}

Answer 3

You can use a toggle to do this and use the ng-class directive to select class depending on the toggle. Here's how you'd do it-
<div ng-init="icon='class1'">
<md-button class="md-icon-button" aria-label="Favorite" hide-gt-sm ng-click="openLeftMenu()">
<md-icon>
<i ng-class="icon">menu</i>
</md-icon>
</md-button>
</div>
In your openLeftMenu() function, handle the classes on click.
function openLeftMenu() {
...
if(icon==='class1'){
icon = 'class2';
} else {
icon = 'class1';
}
...
}
Here class1 and class2 are your icon classes.

Answer 4

Use a flag value set it to true/false and after clicking on the button change the value accordingly and use following code.
<md-button class="md-primary md-raised" ng-click="openLeftMenu()">
<md-icon md-font-icon ng-class="
{'zmdi zmdi-upload': vm.flag,
'zmdi zmdi-code': !vm.flag
}"></md-icon>
</md-button>