如何在AngularJS中将数据从一个异步传递到另一个异步函数 [英] How to pass data from one asynchronous to another asynchronous function in AngularJS

问题描述

我有2个全局变量，如下:

I have 2 global variables as:

$scope.genewtId = null;
$scope.data1 = null;

我有2个角度函数，如下所示:

I have 2 angular functions which look as below:

$scope.getID = function() {
    Service1.getId("abc").then(function(response){
        $scope.genewtId = response.data[0].Id;
        console.log($scope.genewtId);

    }, function(error){
        console.log(error.statusText);
    });
};

$scope.getDetails = function() {
    Service2.getDetails($scope.genewtId).then(function(response){
        // here response is having an error
        $scope.data1 = response.data;
        console.log($scope.data1.toString());
    }, function(error){
        console.log(error.statusText);
    });
};

当我将$scope.genewtId的值从一个函数传递给另一个函数时，会出现错误

When I pass value of $scope.genewtId from one function to another function, I get an error

消息:无法将类型'java.lang.String'的值转换为所需的类型'java.lang.Integer'；嵌套异常为java.lang.NumberFormatException:对于输入字符串:"null"

message: "Failed to convert value of type 'java.lang.String' to required type 'java.lang.Integer'; nested exception is java.lang.NumberFormatException: For input string: "null""

但是，console.log($scope.genewtId);返回的值787651表示它不为空.

However, console.log($scope.genewtId); is returning a value 787651 which means it is not null.

请建议是否可以使用$rootScope.$broadcast

推荐答案

两个服务的承诺必须链接

修改第一个函数以返回承诺:

The promises from the two services need to be chained

Modify the first function to return a promise:

$scope.getID = function() {
    return Service1.getId("abc").then(function(response){
        $scope.genewtId = response.data[0].Id;
        console.log($scope.genewtId);
        return response.data[0].Id;
    }, function(error){
        console.log(error.statusText);
        throw error;
    });
};

修改第二个函数以既返回promise又接受参数:

Modify the second function to both return a promise and accept an argument:

$scope.getDetails = function(id) {
    var genewtID = id || $scope.genewtId;
    return Service2.getDetails(genewtId).then(function(response){
        $scope.data1 = response.data;
        console.log($scope.data1.toString());
        return response.data;
    }, function(error){
        console.log(error.statusText);
        throw error;
    });
};

然后链这两个承诺:

var promise = $scope.getId();

var promise2 = promise.then(function(id) {
                   return $scope.getDetails(id);
               });

var promise2.then(function(data) {
     console.log(data);
}).catch(function(error) {
     console.log(error);
});

通过使用getId承诺的.then方法，代码在向getDetails发出请求之前会等待id值从服务器到达.

By using the .then method of the getId promise, the code waits for the id value to arrive from the server before making the request to getDetails.

由于调用promise的.then方法将返回新的派生promise，因此很容易创建promise的promise.可以创建任意长度的链，并且由于一个承诺可以用另一个承诺来解决(这将进一步推迟其解决方案)，因此可以在链中的任何点处暂停/推迟对这些承诺的解决.

Because calling the .then method of a promise returns a new derived promise, it is easily possible to create a chain of promises. It is possible to create chains of any length and since a promise can be resolved with another promise (which will defer its resolution further), it is possible to pause/defer resolution of the promises at any point in the chain.

有关更多信息，请参见

• AngularJS $ q服务API参考-链接承诺
• 您错过了承诺的重点

• AngularJS $q Service API Reference - Chaining Promises
• You're Missing the Point of Promises

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