如何添加$ q來執行執行？

Question

我需要訂購我的執行。我需要確保我的COMPLETE coords（）方法完成，一旦它被調用。如何添加承諾或$ q到它？我試着在控制檯上打印，發現coords（）函數的最後一行執行後，coords中的每個循環都完成了。看下面的代碼。我真的很新的角度幫助，請

var appa = angular.module('appa',['firebase','uiGmapgoogle-maps']); 
 
appa.controller('mainCtrl', function($firebaseObject,$scope,$q) { 
 

 
       $scope.coords = function(){ 
 
       
 
       var ref = firebase.database().ref(); 
 
       var latArray = []; 
 
       var lngArray = []; 
 
       var cenlat; 
 
       var cenlng; 
 
        var marker = []; 
 
       ref.once("value") 
 
       .then(function(snapshot) 
 
       { 
 
       snapshot.forEach(function(child) 
 
       { 
 

 
        latArray.push(child.child("Lat").val()); 
 
        console.log(child.child("Lat").val()); 
 
        lngArray.push(child.child("Long").val()); 
 
        var mark = { 
 
        id: child.child("Id").val(), 
 
        coords: { 
 
        latitude: child.child("Lat").val(), 
 
        longitude: child.child("Long").val() 
 
        }, 
 
        options: { title: child.child("Alt").val() } 
 
        }; 
 
        marker.push(mark); 
 
CONSOLE.LOG("wWHY IS THIS PRINTED aFTER??? AND HOW TO HANDLE THIS ??"); 
 
       }); 
 

 
        cenlat = (Math.max.apply(Math,latArray)+Math.min.apply(Math,latArray)/2); 
 
        cenlng = (Math.max.apply(Math,lngArray)+Math.min.apply(Math,lngArray)/2); 
 

 
       }); 
 
       $scope.map.center.latitude = cenlat; 
 
       $scope.map.center.longitude = cenlng; 
 
CONSOLE.LOG("wWHY IS THIS PRINTED BEFORE??? AND HOW TO HANDLE THIS ??"); 
 
}); 
 
       }; 
 

 
       $scope.map = { 
 
       center: 
 
       { 
 
        latitude: 51, 
 
        longitude: 4 
 
         }, 
 
       zoom: 2 
 
         }; 
 

 
     $scope.coords(); 
 
     
 

 

 
    });

Answer 1

您使用的火力，可以輕鬆地檢查返回的兒童將它們存儲在一個變量。然後在forEach循環中遞減變量。

//initialized var a, is having child count 
 
a = snapshot.numChildren();

和下面的完整代碼將創建有序執行，並有一個承諾的基本實現。我已經添加了console.log來顯示順序。我希望它有助於一些如何。

//complete code 
 

 
var appa = angular.module('appa',['firebase','uiGmapgoogle-maps']); 
 
appa.controller('mainCtrl', function($firebaseObject,$scope,$q){ 
 

 
       $scope.coords = function(){ 
 
var q = $q.defer(); 
 
       var ref = firebase.database().ref(); 
 
       var latArray = []; 
 
       var lngArray = []; 
 
       var cenlat; 
 
       var cenlng; 
 
       var a="0"; 
 
       var marker = []; 
 

 
       ref.once("value") 
 
       .then(function(snapshot) 
 
       { 
 
       a = snapshot.numChildren(); 
 
       console.log(a); 
 
       snapshot.forEach(function(child) 
 
       { 
 
        latArray.push(child.child("Lat").val()); 
 
        console.log(child.child("Lat").val()); 
 
        lngArray.push(child.child("Long").val()); 
 
        var mark = { 
 
        id: child.child("Id").val(), 
 
        coords: { 
 
        latitude: child.child("Lat").val(), 
 
        longitude: child.child("Long").val() 
 
        }, 
 
        options: { title: child.child("Alt").val() } 
 
        }; 
 
        a= a-1; 
 
        console.log("this is current"+a); 
 
        marker.push(mark); 
 
       }); 
 
console.log("hi"+a); 
 
console.log("going for cenlat"+cenlat); 
 
      cenlat = (Math.max.apply(Math,latArray)+Math.min.apply(Math,latArray)/2); 
 
console.log("done with cenlat"+cenlat); 
 
console.log("going for cenlng"+cenlng); 
 
      cenlng = (Math.max.apply(Math,lngArray)+Math.min.apply(Math,lngArray)/2); 
 
console.log("done with cenlng"+cenlng); 
 
      $scope.map.center.latitude = cenlat; 
 
      $scope.map.center.longitude = cenlng; 
 
      if(a==0){ 
 
      q.resolve('resolved'); 
 
      } 
 
      else{ 
 
      q.reject('rejected'); 
 
      } 
 
       }); 
 

 
       }; 
 
       $scope.map = { 
 
       center: 
 
       { 
 
        latitude: 51, 
 
        longitude: 4 
 
         }, 
 
       zoom: 2 
 
         }; 
 

 
    $scope.coords().then(
 
     function(v){ 
 
console.log(v); 
 
     }, 
 
    function(err){ 
 
console.log(err); 
 
    }); 
 

 
    });