Question

我有一个指令，应该在服务变量发生变化时调用函数。

以下代码在指令中：

$rootScope.$watch('movesService.selectedMove', function() {
    console.log(movesService.selectedMove);
    if (movesService.selectedMove === "Punch") {
      vm.pushToFightLog('Select Target');
    }
    if (movesService.selectedMove === "Fury") {
      //Action
    }
    if (movesService.selectedMove === "Fortify") {
      //Action
    }
    if (movesService.selectedMove === "Parry") {
      //Action
    }
  }, true);

服务：

 angular
    .module('outerZone')
    .service('movesService', movesService);

  function movesService() {
    var vm = this;

    vm.selectedMove = "Punch";


  }

事情是，当第一次调用$ watch时，它能够读取变量并将其记录到控制台，但即使在此之后更改变量，它也不会触发该函数。

我非常确信$ rootScope已正确注入，但这里的代码只是为了仔细检查。

angular
    .module('outerZone')
    .directive('fightDisplay', fightDisplay);

  fightDisplay.$inject = ["alliesService", "enemiesService", "fightQueueService", "$timeout", "movesService", "$rootScope"];

  function fightDisplay(alliesService, enemiesService, fightQueueService, $timeout, movesService, $rootScope) {

Answer 1

使用您提供的plunker，我在手表功能中做了一些更改，如下所示。

exec Table_CHANGES('value2')

如果我们想要严格检查，请更改$scope.$watch('test', function() { //scope variable should be watched like this $scope.watchCount++ });//removed true for strict checking (===) as $scope.test is initalised as String 'Hello'和

$scope.test =0

以下是工作plunker。要了解$ watch（）的工作原理，请查看此blog

AngularJS $观察表现不如预期

1 个答案: