角度同步http循环更新进度条

Question

我正在尝试使用foreach中的顺序http请求更新进度条,这样可行,但是完全没有同步,进度条正在被http调用同步,我做错了什么？

angular.forEach(queue, function (item) {
    if (item.uid) {
        d.item = item;
        $http({
            url: BASE_URL + 'upp', 
            method: 'post',
            data: d                  
        }).then(function(res){
            x++;
            update_progress((x/queue_count)*100);
        });
    }
});

我想在http返回完成时调用update_progress函数(200 OK),因此进度条正确显示实际进度.谢谢!

编辑:

我在调用*update_progress*函数之前尝试检查响应状态,但仍然无法按预期工作.我不知道在请求完成之前已经发送了200个:| 通过逻辑,res obj不应该是http请求的响应？我的意思是,如果它是200而不是错误代码,那不应该意味着请求已经完成了吗？

angular.forEach(queue, function (item) {
if (item.uid) {
    d.item = item;
    $http({
        url: BASE_URL + 'upp', 
        method: 'post',
        data: d                  
    }).then(function(res){
        if(res.status == 200) {
          x++;
          update_progress((x/queue_count)*100);
        }
    });
}

阅读更多承诺atm,看看我是否可以按照@josh-strange的说法使其工作

编辑2:

所以承诺是这样做的方式,所有请求都是按顺序发送的,因此进度条按预期工作,这里是代码:

var promise = $q.all({}); 
// Had to init $q.all with an empty obj, 'cause null was trowing errors

angular.forEach(queue, function(item){
  if (item.uid) {        
    promise = promise.then(function(){
      d.item = item;
      return $http({
        url: BASE_URL + 'upp', 
        method: 'post',
        data: d 
      }).then(function(res){
        x++;
        update_progress((x/queue_count)*100);
      });
    });
  }
});

promise.then(function(){
  end_js_update();
});

谢谢@josh-strange

Answer 1

Here is a working Plunker of a working example of sequential http requests. You could obviously package this up very nicely in a service but for your purposes I just put a simple example of it in a controller.

Here is the "meat" of the code:

var app = angular.module('testApp',[]);

app.controller('myController', function($scope, $http, $q){

  $scope.responses = [];
  $scope.doneLoading = false;
  var urls = [
    'http://httpbin.org/ip',
    'http://httpbin.org/user-agent',
    'http://httpbin.org/headers'
  ];

  var promise = $q.all(null);

  angular.forEach(urls, function(url){
    promise = promise.then(function(){
      return $http({
        method: 'GET', 
        url:url 
      }).then(function(res){
        $scope.responses.push(res.data);
      });
    });
  });

  promise.then(function(){
    //This is run after all of your HTTP requests are done
    $scope.doneLoading = true;
  })

});

EDIT: As Mike P says below: This is an example of chaining promises see $q documentation.