Retrofit can't connect to hapi server localhost?

Question

I'm building android apps using retrofit as my httprequest to connect to my hapi server. my server is working fine, I've test it on postman and my WebApps. But my retrofit can not connect to it. below is my code. For the sake of simplicity to read I delete lines that not necessary:

LoginActivity.java

package com.sianghee.reviu;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.support.design.widget.TextInputEditText;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import butterknife.ButterKnife;
import butterknife.BindView;
import butterknife.OnClick;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

import com.sianghee.reviu.interfaces.APIService;
import com.sianghee.reviu.lib.Session;
import com.sianghee.reviu.models.UserLogin;
import static com.sianghee.reviu.lib.Helper.returnError;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;

public class LoginActivity extends Activity {
    private static final String TAG = "LoginActivity";
    private static final int REQUEST_SIGNUP = 0;
    Session session;
    public static final String BASE_URL = "localhost:3000";

    private EditText emailText;
    private EditText passwordText;

     @BindView(R.id.btn_login) Button _loginButton;
    @BindView(R.id.link_signup) TextView _signupLink;

    // TODO: Init sewaktu pertama kali form diload
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        ButterKnife.bind(this);

        emailText = (EditText)findViewById(R.id.input_email);
        passwordText = (EditText)findViewById(R.id.input_password);

    }

    // TODO: bind login and do login
    @OnClick(R.id.btn_login)
    public void submitLogin() {
        login();
    }

    // TODO: bind signup and do register
    ....

    public void login() {
        Log.d(TAG, "Login");

        if (!validate()) {
            onLoginFailed();
            return;
        }

        _loginButton.setEnabled(false);

        final ProgressDialog progressDialog = new ProgressDialog(this);
        progressDialog.setIndeterminate(true);
        progressDialog.setMessage("Authenticating...");
        progressDialog.show();

        String email = emailText.getText().toString();
        String password = passwordText.getText().toString();

        // TODO: Implement your own authentication logic here.
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .build();

        APIService api = retrofit.create(APIService.class);
        UserLogin userLogin = new UserLogin(email, password);

        Call<UserLogin> call = api.login(userLogin);
        call.enqueue(new Callback<UserLogin>() {
            @Override
            public void onResponse(Call<UserLogin> call, Response<UserLogin> response) {
                String result;
                progressDialog.dismiss();
                try {
                    result = response.body().toString();

                    if (returnError(result).isEmpty()) {

                        JSONObject obj;
                        obj = new JSONObject(result);
                        session.setLoginSession(obj.getString("scope"), obj.getString("token"));

                        Intent i = new Intent(LoginActivity.this, MainActivity.class);
                        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
                        startActivity(i);
                        finish();

                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }

            .......
}

APIService.java

package com.sianghee.reviu.interfaces;

import retrofit2.Call;
import retrofit2.http.Body;
import retrofit2.http.POST;

import com.sianghee.reviu.models.UserLogin;

/**
 * Created by andy on 11/26/17.
 */

public interface APIService {
    @POST("auth")
    Call<UserLogin> login(@Body UserLogin auth);
}

UserLogin.java

package com.sianghee.reviu.models;

public class UserLogin {
    String email;
    String password;

    public UserLogin(String email, String password) {
        this.email = email;
        this.password = password;
    }
}

Whenever I clicked the login button, It's failed to connect to server. below is the logcat:

12-02 23:24:42.771 3660-3660/com.sianghee.reviu I/InstantRun: starting instant run server: is main process
12-02 23:24:43.116 3660-3690/com.sianghee.reviu D/OpenGLRenderer: HWUI GL Pipeline
12-02 23:24:43.213 3660-3660/com.sianghee.reviu I/TextInputLayout: EditText added is not a TextInputEditText. Please switch to using that class instead.
12-02 23:24:43.219 3660-3660/com.sianghee.reviu I/TextInputLayout: EditText added is not a TextInputEditText. Please switch to using that class instead.

                                                                   [ 12-02 23:24:43.283  3660: 3690 D/         ]
                                                                   HostConnection::get() New Host Connection established 0x896438c0, tid 3690
12-02 23:24:43.471 3660-3690/com.sianghee.reviu I/zygote: android::hardware::configstore::V1_0::ISurfaceFlingerConfigs::hasWideColorDisplay retrieved: 0
12-02 23:24:43.471 3660-3690/com.sianghee.reviu I/OpenGLRenderer: Initialized EGL, version 1.4
12-02 23:24:43.471 3660-3690/com.sianghee.reviu D/OpenGLRenderer: Swap behavior 1
12-02 23:24:43.471 3660-3690/com.sianghee.reviu W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
12-02 23:24:43.471 3660-3690/com.sianghee.reviu D/OpenGLRenderer: Swap behavior 0
12-02 23:24:43.473 3660-3690/com.sianghee.reviu D/EGL_emulation: eglCreateContext: 0x9b543860: maj 2 min 0 rcv 2
12-02 23:24:43.475 3660-3690/com.sianghee.reviu D/EGL_emulation: eglMakeCurrent: 0x9b543860: ver 2 0 (tinfo 0xa4a8f700)
12-02 23:24:43.527 3660-3690/com.sianghee.reviu D/EGL_emulation: eglMakeCurrent: 0x9b543860: ver 2 0 (tinfo 0xa4a8f700)
12-02 23:24:43.856 3660-3660/com.sianghee.reviu I/AssistStructure: Flattened final assist data: 1684 bytes, containing 1 windows, 5 views
12-02 23:24:49.113 3660-3673/com.sianghee.reviu I/zygote: Do partial code cache collection, code=30KB, data=26KB
12-02 23:24:49.113 3660-3673/com.sianghee.reviu I/zygote: After code cache collection, code=30KB, data=26KB
12-02 23:24:49.113 3660-3673/com.sianghee.reviu I/zygote: Increasing code cache capacity to 128KB
12-02 23:24:51.355 3660-3673/com.sianghee.reviu I/zygote: Do partial code cache collection, code=61KB, data=59KB
12-02 23:24:51.356 3660-3673/com.sianghee.reviu I/zygote: After code cache collection, code=61KB, data=59KB
12-02 23:24:51.356 3660-3673/com.sianghee.reviu I/zygote: Increasing code cache capacity to 256KB
12-02 23:24:54.016 3660-3673/com.sianghee.reviu I/zygote: Do full code cache collection, code=123KB, data=99KB
12-02 23:24:54.016 3660-3673/com.sianghee.reviu I/zygote: After code cache collection, code=107KB, data=66KB
12-02 23:24:56.503 3660-3660/com.sianghee.reviu D/LoginActivity: Login
12-02 23:24:56.573 3660-3673/com.sianghee.reviu I/zygote: Do partial code cache collection, code=114KB, data=93KB
12-02 23:24:56.573 3660-3673/com.sianghee.reviu I/zygote: After code cache collection, code=114KB, data=93KB
12-02 23:24:56.573 3660-3673/com.sianghee.reviu I/zygote: Increasing code cache capacity to 512KB
12-02 23:24:56.574 3660-3673/com.sianghee.reviu I/zygote: JIT allocated 56KB for compiled code of void android.view.View.<init>(android.content.Context, android.util.AttributeSet, int, int)
12-02 23:24:56.603 3660-3660/com.sianghee.reviu D/NetworkSecurityConfig: No Network Security Config specified, using platform default
12-02 23:24:56.803 3660-3660/com.sianghee.reviu W/error: java.net.ConnectException: Failed to connect to /127.0.0.1:3000
12-02 23:24:57.094 3660-3690/com.sianghee.reviu D/EGL_emulation: eglMakeCurrent: 0x9b543860: ver 2 0 (tinfo 0xa4a8f700)
12-02 23:24:57.126 3660-3690/com.sianghee.reviu D/EGL_emulation: eglMakeCurrent: 0x9b543860: ver 2 0 (tinfo 0xa4a8f700)

My server API Url for login is : http://127.0.0.1:3000/auth

notice that error from my Log.w() method before that say:

java.net.ConnectException: Failed to connect to /127.0.0.1:3000

Maybe this is just my common mistake, please help.

Answer 1

127.0.0.1 is your localhost / loopback address a of your Machine (on which server is hosted). 127.0.0.1 is mapped to the IP address of the machine, hence http://127.0.0.1:3000/auth is accessible from your machine only.

Now, in order to access http://127.0.0.1:3000/auth from any other machine (ie your phone in this case), your machine (server) and device (phone) should be on the same network (eg same Wi-Fi) You need to access it via http://IPAddressOfYourMachine:3000/auth .

On MacOs / Linux you can find out the IP address using ifconfig command on a terminal. On a Windows machine the command is ipconfig . The IP address should be of the form of 192.168.xy

So the final BASE_URL should be something like http://192.168.xy:3000

Answer 2

Retrofit hasn't any problem. The issue is in the BASE_URL for reaching from your android device to your server.

Please check your computer's local ip address that the server is installed in (ex: 192.168.1.103), then replace the BASE_URL with that such as following example

public static final String BASE_URL = "http://192.168.1.103:3000";

Answer 3

确保您的手机（模拟器）和您的计算机在同一网络中并使用 IP 地址http://192.168.8.106:3030例如，而不是http://localhost:3030