如何将 AsyncTask 转换为 Retrofit 以从 Android 中的 WCF Webservice 获取数据

Posted 2023-05-07

【中文标题】如何将 AsyncTask 转换为 Retrofit 以从 Android 中的 WCF Webservice 获取数据

【英文标题】：How can convert AsyncTask to Retrofit for get data from WCF Webservice in Android

【发布时间】：2015-09-29 00:30:12

【问题描述】：

我有一个 WCF 网络服务，它以 JSON 格式返回 SQL Server 数据库数据，现在我正在使用 AsyncTask 通过这段代码在 android 中获取这些数据：

public class FetchInfo extends AsyncTask 

private String year = "94";
private String month = "1";
private String requested_column = "";
private String kodemelli = "";

public FetchInfo(String year, String month,String requested_column, String kodemelli) 
    this.year = year;
    this.month = month;
    this.requested_column = requested_column;
    this.kodemelli = kodemelli;

@Override
protected String doInBackground(Object[] params) 
    try 
        System.out.println("guru");
        DefaultHttpClient httpClient=new DefaultHttpClient();

        //Connect to the server
        HttpGet httpGet=new HttpGet("http://SERVERIP:8005/Service1.svc/checkLogin1?year="+year+"&month="+month+"&requested_column="+requested_column+"&kode_melli="+kodemelli);
        //Get the response

        String result = "";
        HttpResponse httpResponse = httpClient.execute(httpGet);
        HttpEntity httpEntity = httpResponse.getEntity();
        InputStream stream=httpEntity.getContent();
        result = convertStreamToString(stream);
        //Convert the stream to readable format
        if (result.contains("\"error\"") || result.contains("\"server error\""))
            Main.result = "0";
            MainFish.result = "0";
        else 
            Main.result = result;
            MainFish.result = result;
        

     catch (Exception e) 
        Main.result = "error";
        MainFish.result = "error";
    

    return "";

public static String convertStreamToString(InputStream is)

    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();

    String line = null;
    try 
        while ((line = reader.readLine()) != null) 
            sb.append(line + "\n");
        
    
    catch (IOException e) 
        e.printStackTrace();
    
    finally 
        try 
            is.close();
         catch (IOException e) 
            e.printStackTrace();
        
    
    return sb.toString();

这样，当请求超过例如10个请求时，响应时间很长。 从这个主题How to speed up fetching of data from server using JSON? 我意识到我应该使用 Retrofit 而不是 AsyncTask 来使我的程序工作。

现在我的问题是如何将 AsyncTask 类转换为 Retrofit？

【问题讨论】：

现在我的问题是如何将此 AsyncTask 类转换为 Retrofit ？ ...通过重构/重写代码...问题出在哪里？你试过了吗？还是您要免费代码？

【参考方案1】：

好的，首先你不会使用带有改造的异步任务。改造负责异步部分。首先你需要定义一个休息适配器。

这是一个默认的休息适配器，其中包含您的参数。

public class ApiClient 

private static ApiInterface sApiInterface;

public static ApiInterface getApiClient(Context context) 

//build the rest adapter
if (sApiInterface == null) 
    final RestAdapter restAdapter = new RestAdapter.Builder()
            .setEndpoint("http://SERVERIP:8005")
            .build();
    sApiInterface = restAdapter.create(ApiInterface.class);

return sApiInterface;



public interface ApiInterface 
// /Service1.svc/checkLogin1?year="+year+"&month="+month+"&requested_column="+requested_column+"&kode_melli="+kodemelli
@GET("/Service1.svc/checkLogin1")
void getYourObject(
    @Query("year") String year,       
    @Query("month") String month,    
    @Query("requested_column") String requested_column,
    @Query("kode_melli") String kodemelli,
    RetrofitCallback<YourObjectModel> callback);

在您拥有一个休息适配器后，您需要一个模型来放入数据。使用jsonschema2pojo 将有效的 JSON 转换为 POJO 模型。这是我的一个 json 响应及其模型的示例。

"id": "37",
"title": "",
"short_name": "",
"short_description": "",
"full_description": "",
"url": "http:\/\/\/shows\/programname",
"Image": 
    "url": "https:\/\/s3.amazonaws.com\/image\/original\/b2mWDPX.jpg",
    "url_sm": "https:\/\/s3.amazonaws.com\/image\/small\/b2mWDPX.jpg",
,
"image": "b2mWDPX.jpg",
"hosts": [
    "id": "651",
    "display_name": "",
    "username": "",
    "Image": 
        "url": "https:\/\/s3.amazonaws.com\/image\/original\/selfie.jpg",
        "url_sm": "https:\/\/s3.amazonaws.com\/image\/small\/selfie.jpg",
    
],
"airtimes": [
    "start": "11:00:00",
    "end": "13:30:00",
    "weekday": "6"
],
"categories": [
    "id": "84",
    "title": "Bluegrass",
    "short_name": "bluegrass"
],
"meta": []

我得到了这个模型。以及其他一些人。

public class Program 
@Expose
private doublea.models.Airtime Airtime;
@Expose
private String id;
@Expose
private String title;
@SerializedName("short_name")
@Expose
private String shortName;
@SerializedName("full_description")
@Expose
private String fullDescription;
@SerializedName("short_description")
@Expose
private String shortDescription;
@Expose
private doublea.models.Image Image;
@SerializedName("image")
@Expose
private String imageName;
@Expose
private List<Host> hosts = new ArrayList<Host>();
@Expose
private List<Category> categories = new ArrayList<Category>();
@Expose
private List<Airtime> airtimes = new ArrayList<Airtime>();

/** Getters and Setters */

public Program() 

然后确保您处理失败案例。

public class RetrofitCallback<S> implements Callback<S> 
private static final String TAG = RetrofitCallback.class.getSimpleName();


@Override
public void success(S s, Response response) 



@Override
public void failure(RetrofitError error) 
    Log.e(TAG, "Failed to make http request for: " + error.getUrl());
    Response errorResponse = error.getResponse();
    if (errorResponse != null) 
        Log.e(TAG, errorResponse.getReason());
        if (errorResponse.getStatus() == 500) 
            Log.e(TAG, "Handle Server Errors Here");
        
    

最后进行 api 调用。

private void executeProgramApiCall(String year, String month, String requested_column, String kodemelli) 
ApiClient.getApiClient(this).getProgram(year, month, requested_column, kodemelli, new RetrofitCallback<Program>() 

    @Override
    public void success(YourObjectModel program, Response response) 
        super.success(YourObjectModel , response);
        //TODO: Do something here with your ObjectMadel
    
);

我强烈建议您查看retrofit 文档，以防您需要任何特殊的东西，例如标头或请求拦截器。