如何在Android中使用WebService？

Question

I have made a webservice in asp.net, the method looks like this:

[WebMethod]
    public string getUser(string usr)
    {

        var json = "";
        var user = from result in dc.Persons
                   where result.username == usr
                   select result.password;

        JavaScriptSerializer jss = new JavaScriptSerializer();
       json = jss.Serialize(user);
        return json;
    }

It returns the passowrd from the specified user.

However how can I use this method in my android app ?

Say that I wanted to get the password for user: Rambo ?

Answer 1

Well for this usually we use REST webservice with using GET/Post. Use Volley for this the net has many examples how to use it. this is my favorite: Tutorial for Volley

Example.URL: http://DomainOrIpAdress/Accounts/getPassword?user=Rambo <- this is GET Request OR
             http://DomainOrIpAdress/Accounts/getPassword <- this is POST Request

And the tutorial shows how to get the response you return a json then you have to use JsonObjectRequest. Well this is how I done it many many times.

Answer 2

In Android, you need to use AnyncTask to run the httpget call in background like this.

private final String API_URL = "www.example.com/api/{YourControllerName}/getUser?usr="
private class HttpGetter extends AsyncTask<URL, Void, Void> {

                @Override
                protected Void doInBackground(arg... args) {
                        // TODO Auto-generated method stub
                        StringBuilder builder = new StringBuilder();
                        HttpClient client = new DefaultHttpClient();
                        HttpGet httpGet = new HttpGet(API_URL + arg[0]);

                        try {
                                HttpResponse response = client.execute(httpGet);
                                StatusLine statusLine = response.getStatusLine();
                                int statusCode = statusLine.getStatusCode();
                                if (statusCode == 200) {
                                        HttpEntity entity = response.getEntity();
                                        InputStream content = entity.getContent();
                                        BufferedReader reader = new BufferedReader(
                                                        new InputStreamReader(content));
                                        String line;
                                        while ((line = reader.readLine()) != null) {
                                                builder.append(line);
                                        }
                                        Log.v("Getter", "Your data: " + builder.toString()); //response data
                                } else {
                                        Log.e("Getter", "Failed");
                                }
                        } catch (ClientProtocolException e) {
                                e.printStackTrace();
                        } catch (IOException e) {
                                e.printStackTrace();
                        }

                        return null;
                }
    }

HttpGetter get = new HttpGetter();
get.execute("Rambo");