Hello, based on your question it seems like you are looking to modify the color of a button when clicked using ng-click.
I have provided a JsFiddle link where I have demonstrated two buttons:
One button changes color on click and does not reset to default
The other button alternates between default and alternate colors on each click
Here is the JsFiddle link for reference
Feel free to check it out and let me know if this solution addresses your query.
<div ng-app="myApp" ng-controller="myCtrl">
<div ng-view="">
<button type="button" class="btn" ng-class="color ? 'btn-success' : ''" ng-click="btnClick()" >Success</button>
<button type="button" class="btn" ng-class="color2 ? 'btn-warning' : 'btn-success'" ng-click="btnclick2()">Alternate</button>
</div>
</div>