How to solve NameValuePair cannot be a String in Android

Question

I'm learning how to build android Apps, and I'm trying to insert values into my Database using Java and PHP. But NameValuePair is giving me multiple errors.

I already imported the necessary files. What am I doing wrong?

My PHP file:

$connect = mysqli_connect("localhost","root","","users");

if(mysqli_connect_errno($connect))
{
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
else
{
    echo "success";
}

$username=$_REQUEST['username'];
$password=$_REQUEST['password'];
$result = mysql_query(" insert into users(username,password)   values('$username','$password')"  );
if($result == 1)
{
    // successfully inserted
    $response["success"] = 1;
    $response["message"] = "User created.";

    // echoing JSON response
    echo json_encode($response);
}
else
{
    // failed to insert row
    $response["success"] = 0;
    $response["message"] = "Oops! An error occurred.";

    // echoing JSON response
    echo json_encode($response);

}

Java XML:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.registro.MainActivity" >

    <EditText
        android:id="@+id/editText2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/editText1"
        android:layout_below="@+id/editText1"
        android:layout_marginTop="70dp"
        android:ems="10"
        android:text="Password"
         >

    </EditText>

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_marginLeft="18dp"
        android:layout_marginTop="18dp"
        android:ems="10"
        android:text="Username" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/editText2"
        android:layout_below="@+id/editText2"
        android:layout_marginTop="40dp"
        android:text="Button"
        android:onClick="create"
         />

</RelativeLayout>

Main activity file

package com.example.registro;


import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;

import java.util.ArrayList; 
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends ActionBarActivity {

    private EditText usernameField,passwordField;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

          usernameField = (EditText)findViewById(R.id.editText1);
          passwordField = (EditText)findViewById(R.id.editText2);
    }

       public void create(){
              String username = usernameField.getText().toString();
              String password = passwordField.getText().toString();

              // TODO Auto-generated method stub
                HttpClient client = new DefaultHttpClient();
                HttpPost httppost = new HttpPost("http://localhost/example/insert.php");

                try
                {
                    nameValuePairs = new ArrayList<NameValuePair>();
                    nameValuePairs.add(new BasicNameValuePair("username", username));
                    nameValuePairs.add(new BasicNameValuePair("password", password));

                    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
                    response = httpclient.execute(httppost);
                }
                catch(Exception e)
                {
                    e.printStackTrace();
                }
            }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


    }

Answer 1

Try change

public void create(){
          String username = usernameField.getText().toString();
          String password = passwordField.getText().toString();

          // TODO Auto-generated method stub
            HttpClient client = new DefaultHttpClient();
            HttpPost request = new HttpPost("http://localhost/example/insert.php");

            try
            {
                List<NameValuePair>  postparam = new ArrayList<NameValuePair>();
                postparam.add(new BasicNameValuePair("username", username));
                postparam.add(new BasicNameValuePair("password", password));

                httppost.setEntity(new UrlEncodedFormEntity(postparam));
                HttpResponse response = client.execute(request);
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }