AngularJS ng-click 服务和承诺

Question

我一直是 AngularJS 的初学者，并且在...方面存在知识问题 我想做的事情几乎很简单——视图中的一个按钮触发条形码扫描，一旦扫描完成，用扫描结果填充视图字段。

在视图中：

<button id="ajouter-button3" class=" button button-positive  button-block " ng-click="scanBarCode()">Scanner</button>

然后在视图中：

        <label class="item item-input " id="add-ean" name="ean">
            <span class="input-label">EAN</span>
            <input type="text" placeholder="Code EAN" name="add.ean" ng-model="add.ean" value="{{add.ean}}">
        </label>

放置在控制器中：

    .controller("ajouterCtrl", ["$scope", "$ionicPopup", "$timeout", "ScanDatas", "ScanService" , "storageAreaService", function ($scope, $ionicPopup, $timeout, ScanDatas, ScanService, storageAreaService) {
    "use strict";
    $scope.storageAreas = storageAreaService.storageAreaList();
    $scope.add = {}; // Initalise l'objet


    $scope.scanBarCode = function(){
        ScanService.getBarcodeData().then(function(datas){
            console.log("Retour de la méthode d'acquisition");
            $scope.add.ean = datas.text;
        })
    };

}])

而在services.js中，想要在扫描完成后延迟得到一个promise，但是。我不明白 defer / promise / function 是如何协同工作的，我试过这个：

.factory("ScanService", ["$q", "ScanDatas","$cordovaBarcodeScanner", function ($q, ScanDatas, $cordovaBarcodeScanner) {
var scan = {};

var scanBarCode = function(){
    var readDatas = {};

    $cordovaBarcodeScanner.scan().then(function(datas){
        readDatas.text = datas.text;
        readDatas.format = datas.format;
        readDatas.cancelled = datas.cancelled;
        readDatas.processed = true;
    },function(error){
        readDatas.error = true;
    });

    return readDatas;
}

var getBarcodeData = function(){
    var deferred = $q.defer();

    deferred.resolve(scanBarCode());

    return deferred.promise;
};

return {
    getBarcodeData: getBarcodeData
}
}])

当我运行应用程序时...日志会立即在$scope.scanBarCode 中触发，而我预计console.log 只会在deferred.resolve 之后触发promise。我不明白为什么会这样。

Answer 1

将此作为您的服务：

.factory("ScanService", ["$q", "ScanDatas","$cordovaBarcodeScanner", function ($q, ScanDatas, $cordovaBarcodeScanner) {
  var scan = {
    scanBarCode : function(){
      var deferred = $q.defer();
      var readDatas = {};
      $cordovaBarcodeScanner.scan().then(function(datas){
          readDatas.text = datas.text;
          readDatas.format = datas.format;
          readDatas.cancelled = datas.cancelled;
          readDatas.processed = true;
          deferred.resolve(readDatas);
      },function(error){
          readDatas.error = true;
      });

      return deferred.promise;
    }
  };

  return scan;
}]);

并像这样从控制器调用它：

$scope.scanBarCode = function(){
    ScanService.scanBarCode().then(function(datas){
        console.log("Retour de la méthode d'acquisition");
        $scope.add.ean = datas.text;
    })
};

谢谢！