angular.module('tabsDemo1', ['ngMaterial'] )
  .controller('AppCtrl', function( $scope ) {

    $scope.data = {
      selectedIndex : 0,
      secondLocked : true,
      secondLabel : "Item Two"
    };

    $scope.next = function() {
      $scope.data.selectedIndex = Math.min($scope.data.selectedIndex + 1, 2) ;
    };

    $scope.previous = function() {
      $scope.data.selectedIndex = Math.max($scope.data.selectedIndex - 1, 0);
    };
    
  });