各位好, 使用$http時遇到問題, 以下程式碼為:
先透過post取得user list, 再根據個數以for loop送get取得user info

1. 目前已知這會有非同步問題, 但不曉得該如何改寫。
2. 為何userinfo會有資料, 但userinfo[0]是undefined?

MyApp.controller('MyCtrl', function($scope, $http) {
    $scope.UM_FuncSearch = function() {
        $http.post("test", data)
        .then(function(rsp) {
            var length = rsp.data.user_list.length;
            var userlist = rsp.data.user_list;
            var userinfo = [];
            if(length != 0){
                for(var i = 0; i < length; i++){
                    var url = "test?uniqname=" + userlist[i].uniqname;
                    $http.get(url)
                    .then(function(rsp) {
                        var obj = rsp.data.user_info;
                        userinfo.push(obj);
                    });
                }
                console.log(userinfo);
                console.log(userinfo[0]);
            }
        });
    }
});

Edit:
有找到程式碼, 改寫後似乎可以, 但不太懂...:

MyApp.controller('MyCtrl', function($scope, $http, $q) {
    $scope.UM_FuncSearch = function() {
        $http.post("test", data)
        .then(function(rsp) {
            var length = rsp.data.user_list.length;
            var userlist = rsp.data.user_list;
            var userinfo = [];
            if(length != 0){
                for(var i = 0; i < length; i++){
                    var url = "test?uniqname=" + userlist[i].uniqname;
                    userinfo.push(test(url));
                }
                console.log(userinfo);
                console.log(userinfo[0]);
            }
        });
    }
    function test(url){
        var deferred = $q.defer();
        var promise = deferred.promise;
        $http.get(url)
        .then(function(rsp) {
            deferred.resolve(rsp.data.user_info); 
        });
        return promise;
    }
});