如何从子指令调用AngularJS父指令作用域方法

app.directive('parentDirective', function() {
  return {
    restrict: 'E',
    controller: function($scope) {
      $scope.parentMethod = function() {
        // 父指令方法的逻辑
      };
    }
  };
});

app.directive('childDirective', function() {
  return {
    restrict: 'E',
    require: '^parentDirective',
    link: function(scope, element, attrs, parentCtrl) {
      // 在子指令中调用父指令的方法
      parentCtrl.parentMethod();
    }
  };
});

<parent-directive>
  <child-directive></child-directive>
</parent-directive>