agGrid.initialiseAgGridWithAngular1(angular);

var module = angular.module("example", ["agGrid"]);

module.controller("exampleCtrl", function($scope) {
  
  
  
  
        function CustomHeader() {
        }

        CustomHeader.prototype.init = function (agParams) {
            this.agParams = agParams;
            this.eGui = document.createElement('div');
            this.eGui.innerHTML = '<div ng-click="$ctrl.alertMsg()">{{getLabel()}}</div>';
        };


        CustomHeader.prototype.getGui = function () {
            return this.eGui;

        };

        CustomHeader.prototype.destroy = function () {
        };
  
  
  
  
  
  
  
  var ctrl = this;
  
  $scope.alertMsg = function(){
    alert("hi");
  };
  
  $scope.getLabel = function(){
    return "CustomLabel";
  }
  
  var columnDefs = [{
    headerName: "Make",
    field: "make"
  }, {
    headerName: "Model",
    field: "model"
  }, {
    headerName: "Price",
    field: "price",
    cellRenderer: function(){return '<div ng-click="alertMsg()">{{getLabel()}}</div>';}
  }];

  var rowData = [{
    make: "Toyota",
    model: "Celica",
    price: 35000
  }, {
    make: "Ford",
    model: "Mondeo",
    price: 32000
  }, {
    make: "Porsche",
    model: "Boxter",
    price: 72000
  }];

  $scope.gridOptions = {
    columnDefs: columnDefs,
    rowData: rowData,
    angularCompileHeaders: true,
    angularCompileRows: true,
    components: {
        agColumnHeader: CustomHeader
    },
  };

});
<html>

<head>
  <style>
    html,
    body {
      margin: 0;
      padding: 0;
      height: 100%;
    }
  </style>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.5/angular.min.js"></script>
  <script src="https://unpkg.com/ag-grid@15.0.0/dist/ag-grid.js"></script>
</head>

<body>

  <div ng-app="example" ng-controller="exampleCtrl as $ctrl">
    <div ag-grid="gridOptions" class="ag-theme-fresh" style="height: 500px;"></div>
    <button ng-click="alertMsg()">{{getLabel()}}</button>
  </div>

  
  <script src="app.js"></script>
</body>

</html>
/* Put your css in here */