Android app can not connect to localhost server

Question

I've created Database in my localhost, and want parse data from it with android app.I Create server with NodeJS and it works i can see the Database in browser, but my android app can't connect with this localhost server. Here is my Java code.

 public class MainActivity extends AppCompatActivity {

 protected TextView tvData;

 public static ArrayList<String> titleList = new ArrayList<String>();
 private static ArrayAdapter<String> adapter;
 private static ListView lv;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    tvData = (TextView)findViewById(R.id.tvJsonItem);

   // adapter = new ArrayAdapter<String>(this, R.layout.list_item,   R.id.listView1, titleList);
   // lv = (ListView) findViewById(R.id.listView1);

    new JSONTask().execute("http://10.0.2.2:3000/api/people");

 }

 public class JSONTask extends AsyncTask<String,String,String>{
    @Override
    protected String doInBackground(String... params) {
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        int statusCode = 0;

        try {
            URL url = new URL(params[0]);
            connection = (HttpURLConnection) url.openConnection();
            connection.setRequestProperty("Content-Type", "application/json");
            connection.setRequestMethod("GET");
            connection.connect(); //connect to server

            statusCode = connection.getResponseCode();


            if (statusCode ==  200) {
                System.out.println("Server responded with code: " + statusCode);

                InputStream stream = connection.getInputStream();

                reader = new BufferedReader(new InputStreamReader(stream));

                StringBuffer buffer = new StringBuffer();
                String line = "";

                while ((line = reader.readLine()) != null) {
                    buffer.append(line);
                }

                String finalJSON = buffer.toString();
                JSONObject parentObject = new JSONObject(finalJSON);
                JSONArray parentArray = parentObject.getJSONArray("people");

                StringBuffer finalBufferdData = new StringBuffer();

                for (int i = 0; i < parentArray.length(); i++) {

                    JSONObject finalObj = parentArray.getJSONObject(i);

                    String peopleName = finalObj.getString("name");
                    Integer age = finalObj.getInt("age");
                    finalBufferdData.append(peopleName + "-->" + age + "\n");

                    Log.i("Hakob_log",peopleName + "-->" + age + "\n");
                }


                return finalBufferdData.toString(); //pases result to POstExecute
            }else{
                Log.i("Hakob_log","Error");
            }

        }catch(MalformedURLException e){
            e.printStackTrace();
        }catch(IOException e){
            e.printStackTrace();
        }catch(JSONException e){
            e.printStackTrace();
        }
        finally {
            if(connection !=null) {
                connection.disconnect();
            }
            try {
                if(reader !=null) {
                    reader.close();
                }
            }catch(IOException e){
                e.printStackTrace();
            }
        }
        return null;
    }


    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        tvData.setText(result);
    }
}
}

I thnk something wrong with this line

new JSONTask().execute("http://localhost:3000/api/people");

Thanks

Answer 1

请使用您指的是localhost的计算机的IP地址，这应该可以解决您的问题，例如：

new JSONTask().execute("http://10.0.0.100:3000/api/people");