Question

我正在尝试实施一个回调问题，希望你能帮助我。

这是我的HTML：

<a class="btn btn-primary btn-xs address-pager" ng-disabled="citizensCtrl.addressIndex==citizensCtrl.citizen.addresses.length-1" ng-click="citizensCtrl.nextAddress()">
  <span class="glyphicon glyphicon-chevron-right"></span> 
</a>

ng-click中的功能是：

self.nextAddressIndexCallBack = function(){
  console.log('d');
  self.addressIndex = self.addressIndex+1;
};

self.nextAddress = function(){
  if(self.citizen.addresses[self.addressIndex].district){
    self.getAddresses(false);
    self.getZipCodes(self.nextAddressIndexCallBack());
  }
};

在函数中，getZipCodes是我发现问题的地方：

self.getZipCodes = function(callback){
  if(self.citizen.addresses[self.addressIndex].public_place.id){
    $http.get(apiUrl + "/addresses/" + self.citizen.addresses[self.addressIndex].public_place.id + "/zip_codes").then(function(response){
      console.log('a');
      self.zip_codes[self.addressIndex] = response.data;
      console.log('b');
      if(callback){
        callback;
      }
    });
  }
};

所以，我期望的正确的运行时是控制台（a，b，d）。但这是安慰（d，a，b）。

这是实现回调的最佳方式吗？我怎么做才是同步的，只有在getZipCodes函数上调用它才能执行？

Answer 1

self.nextAddressIndexCallBack（）导致函数执行，并将其结果传递给调用函数..

您可以尝试以下更改：

self.nextAddress = function(){
  if(self.citizen.addresses[self.addressIndex].district){
    self.getAddresses(false);
    //self.getZipCodes(self.nextAddressIndexCallBack());
    self.getZipCodes(self.nextAddressIndexCallBack);
  }
};

self.getZipCodes = function(callback){
  if(self.citizen.addresses[self.addressIndex].public_place.id){
    $http.get(apiUrl + "/addresses/" + self.citizen.addresses[self.addressIndex].public_place.id + "/zip_codes").then(function(response){
      console.log('a');
      self.zip_codes[self.addressIndex] = response.data;
      console.log('b');
      if(callback){
        //callback();
        callback();
      }
    });
  }
};

Answer 2

由于括号，您执行的函数<!DOCTYPE html> <html> <body onload="alert('done')"> Put your spinner here. Some text here is necessary here for the browser to start displaying. Otherwise it will wait until it receives enough of a response to begin displaying anything. I am not sure how much is necessary. This works for me. <% out.print(" Starting processing now. "); out.flush(); Thread.sleep(2000); out.print(" Processing..... "); out.flush(); for(int x = 1; x < 4; x++){ Thread.sleep(2000); out.print("Result " + x + ". "); out.flush(); } %> </body> </html>已执行。

只需删除括号，这样就可以在不执行回调的情况下传递回调。

select '{' || array_to_string(array[1,2.1,3.2,8.1,9.0], ' ') || '}';
      ?column?       
---------------------
 {1 2.1 3.2 8.1 9.0}

顺便说一句，这与此question类似。

使用Js Callback的运行时错误

2 个答案: