AngularJS Bootstrap checkbox not checking on click

I have a checkbox I am using in my AngularJS/Bootstrap application and the issue i'm facing is that when I click on it when it's unchecked, it's not showing the checkmark. The toggleVal() method is being called though and it's executing the steps but it's not showing the check mark. Also, my scope variable myvar is either a 0 or a 1 and I want to display it accordingly.

<input ng-click="toggleVal()" class="form-check-input ml-2" type="checkbox"  
  ng-model="myvar"
  ng-checked="myvar"
  ng-true-value="1" ng-false-value="0">