Question

我有这个应用程序使用$ cordovaFileTransfer将文件上传到服务器，然后将有关该文件的数据发送到同一服务器。文件传输正常。然后将数据发送到服务器，服务器响应。但是响应并没有让它回到承诺回调。为什么呢？

$scope.sendPost = function(data) {

  //first upload a file then send more data about the file
  $cordovaFileTransfer.upload('http://example.com', 'myfile.txt', options)
    .then(function(result) {
      var promise = MyFactory.sendFileData(data);
    });

promise.then(function(response) {
  //we never make it to here
});

}

并在MyFactory中：

service.sendFileData = function(data) {
  return $http({
    //bunch of parameters. This function works, data is sent to the server and a response received
  }).then(function(response) {
    //this is fired when the response is received from the server. All is good so far.

  return.response.data

  });
}
return service;

Answer 1

$cordovaFileTransfer.upload返回一个promise对象，您可以使用该对象构建promise链接机制。

<强>代码

$scope.sendPost = function(data) {

    //get hold on `upload` function promise
    var promise = $cordovaFileTransfer.upload('http://example.com', 'myfile.txt', options)
    .then(function(result)) {
          //return MyFactory.sendFileData promise here which will follow promise chaining
          return MyFactory.sendFileData(data);
        });
    //promise.then will get call once `MyFactory.sendFileData` complete it
    promise.then(function(response) {
        //will get called once `sendFileData` complete its promise
    });
}

Answer 2

因为您正在转发另一个承诺回调以启动承诺，并且...很可能在承诺初始化之前您附加一个回调它...所以在你附加回调时，承诺尚未初始化，即promise是null ..所以在你的控制台中你会看到一个错误。

尝试做一些像

这样的事情

var x = function(response) {
  //we'll make it to here now...
}
$cordovaFileTransfer.upload('http://example.com', 'myfile.txt', options)
    .then(function(result)) {
      var promise = MyFactory.sendFileData(data);
      promise.then(x);
     });

你应该遵循@PankajParkar解决方案，虽然这是一个更好的方法......

Answer 3

$scope.sendPost = function(data) {

//first upload a file then send more data about the file
$cordovaFileTransfer.upload('http://example.com', 'myfile.txt', options)
.then(function(result)) {
  return MyFactory.sendFileData(result.data);
})
.then(function(response) {

});

Angular承诺回调没有解雇

3 个答案: