在foreach循环

Question

我正在使用forEach循环来上传图像（API调用），我希望循环等到Previous index的响应到来。 这是我的代码：

var uploadCount = 0;
angular.forEach($scope.selectedLayouts, function (layout, pIndex) {
  angular.forEach(layout.data, function (data, cIndex) {
    if(data.imageIsChanged && $scope.uploadImgCount !== 0) {
      Upload.upload({
        url: window.apiUrl + 'image_upload',
        data: {
          'image' : data[$scope.indexes.image]
        }
      }).then(function(resp) {
        uploadCount++;
        data[$scope.indexes.image] = resp.data.path;
        if($scope.uploadImgCount === uploadCount) {
          $scope.uploadImgCount = uploadCount = 0;
        }
      }, function(error) {
        uploadCount++;
        toastr.error(error);
      });
    }
  });
});

Answer 1

function PostData(myArray) {

  var i = 0; // Array index counter
  var deferred = $q.deferred(); // Create promise using $q.deferred();

  var promises = [] // An array of your request results as promises

  function nextRequest() {  // make the next request in you array    
   var request_promise = Upload.upload({
     var postData = myArray[i];
      // the rest of your code ...
   }) // assumes Upload.upload returns a promise
   .then( function (data){
     // OnSuccess callback
     promises.push(data); // save result in array
     i++; // increment index

     // Continue if there are more items.
     if (currentRequest < someArray.length){
       nextRequest();
     }      
     else { // Resolve the promise when finished
      deferred.resolve(results);  
     }  
    }, function(error){
      // errorcallback
    }
  )};

  return deferred.promise; // return a promise for the completed requests
}

然后调用该函数并解决承诺

PostData(myArray).then(function(success){
    // successcallback
  }, function(error){
    // errorcallback
});

请注意，我实际上没有实现上面的代码，但这应该为您提供一种可能的方法。