AFHTTPRequestOperationManager在块中返回数据 [英] AFHTTPRequestOperationManager return data in block

问题描述

我在应用程序中创建了一个APIController，该APIController具有几种方法，这些方法可以调用特定的api URL，并返回填充有api调用结果的模型对象.

I created an APIController in my application that has several methods that call specific api urls and return a model object populated with the result of the api call.

该api可与json一起使用，到目前为止，我的代码如下所示:

The api works with json and up to now my code looks like the following:

//Definition:
- (MyModel *)callXYZ;
- (MyModel *)callABC;
- (MyModel *)call123;

//Implementation of one:
- (MyModel *)callXYZ {

    //Build url and call with [NSData dataWithContentsOfURL: url];
    //Create model and assign data returned by api

    return model;

}

现在，我想使用出色的AFNetworking框架摆脱"dataWithContentsOfURL"调用.所以我改变了我的方法:

Now I want to use the great AFNetworking framework to get rid of that "dataWithContentsOfURL" calls. So I changed my methods:

- (MyModel *)callXYZ {
    __block MyModel *m;
    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    [manager GET:urlString parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
        //process data and assign to model m
    }
    return m;
}

该代码将无法工作，因为在url调用完成之前将返回空模型.我被困住了，不知道如何重构我的设计才能使其正常工作.

This code won't work cause the empty model gets returned before the url call has finished. I am stuck and don't know how to refactor my design to get this to work.

//不知道是否重要，但是我稍后想在调用api时显示加载动画.

// I don't know if it is important to know, but I later want to show a loading animation while the api gets called.

推荐答案

- (void)callXYZWithCompletion:(void (^)(MyModel *model))completion {
    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];

    [manager GET:urlString parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
        MyModel *m;
        //process data and assign to model m

        if(completion) {
            completion(m);
        }
    }
}

用法示例:

// Start the animation

[self callXYZWithCompletion:^(MyModel *model) {
    // Stop the animation
    // and use returned model here
}];

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