// Api.java

import java.util.List;

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

public interface Api {

    String BASE_URL = "http://10.0.2.2:3000/";

    @GET("users")
    Call<List<User>> getUsers();

    @POST("users")
    Call<User> createUser(@Body User user);

}


// user class

public class User {
public String name;
public  String email;
public String password;

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}


// Main Activity .. layout...

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Enter the user details"
    android:textAlignment="center"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:weightSum="3">

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="Name"
            android:textAlignment="center"
            android:layout_weight="1"/>
        <EditText
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:id="@+id/username"
            android:layout_weight="2"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:weightSum="3">

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="Email"
            android:textAlignment="center"
            android:layout_weight="1"/>
        <EditText
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:id="@+id/email"
            android:layout_weight="2"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:weightSum="3">

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="Password"
            android:textAlignment="center"
            android:layout_weight="1"/>
        <EditText
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:id="@+id/password"
            android:layout_weight="2"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:weightSum="2">

        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="Submit"
            android:layout_weight="1"
            android:id="@+id/submit"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="Retrieve"
            android:layout_weight="1"
            android:id="@+id/retrieve"/>

    </LinearLayout>
    <ListView
        android:id="@+id/listViewUsers"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>



/// Main Java class


package giri.amity.noidaworkshop;
 import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.ArrayAdapter;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.ListView;
 import android.widget.Toast;

 import java.util.List;

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

public class MainActivity extends AppCompatActivity {
     ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button submit = (Button)findViewById(R.id.submit);
        submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final EditText name = (EditText)findViewById(R.id.username);
                final EditText email = (EditText)findViewById(R.id.email);
                final EditText password = (EditText)findViewById(R.id.password);
                User user = new User(name.getText().toString(),email.getText().toString(),password.getText().toString());
                Retrofit retrofit = new Retrofit.Builder()
                        .baseUrl(Api.BASE_URL)
                        .addConverterFactory(GsonConverterFactory.create())
                        .build();


                Api api = retrofit.create(Api.class);
                Call<List<User>> call = api.getUsers();
                Api api1 = retrofit.create(Api.class);
                Call<User> call1 = api1.createUser(user);
                call1.enqueue(new Callback<User>() {
                    @Override
                    public void onResponse(Call<User> call, Response<User> response) {
                        Toast.makeText(getApplicationContext(), response.message(), Toast.LENGTH_LONG).show();
                        name.setText("");
                        email.setText("");
                        password.setText("");


                    }

                    @Override
                    public void onFailure(Call<User> call, Throwable t) {



                    }
                });
            }
        });

        Button retrieve = (Button)findViewById(R.id.retrieve);
        retrieve.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getUsers();

            }
        });

        listView = (ListView) findViewById(R.id.listViewUsers);

        //calling the method to display the heroes



    }
   public void getUsers(){


       Retrofit retrofit = new Retrofit.Builder()
               .baseUrl(Api.BASE_URL)
               .addConverterFactory(GsonConverterFactory.create())
               .build();


       Api api = retrofit.create(Api.class);
       Call<List<User>> call = api.getUsers();

       call.enqueue(new Callback<List<User>>() {
           @Override
           public void onResponse(Call<List<User>> call, Response<List<User>> response) {
               List<User> usersList = response.body();
               String[] users = new String[usersList.size()];

               //looping through all the heroes and inserting the names inside the string array
               for (int i = 0; i < usersList.size(); i++) {
                   users[i] = usersList.get(i).getName();
               }


               //displaying the string array into listview
               listView.setAdapter(new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, users));

           }

           @Override
           public void onFailure(Call<List<User>> call, Throwable t) {
               Log.d("hello", t.toString());
               Toast.makeText(getApplicationContext(), t.getMessage(), Toast.LENGTH_LONG).show();

           }
       });

   }
}




// retrofit ...  dependency


  implementation 'com.squareup.retrofit2:retrofit:2.5.0'
  implementation 'com.squareup.retrofit2:converter-gson:2.4.0'


// internet permission and application cleartexttraffic

        android:usesCleartextTraffic="true"