<?php
//Datos BD
$user = "id6152109_admin";
$pass = "admin";
$bd = "id6152109_kiriki";
$server = "localhost";

if(isset($_POST['password'])){
    $E = $_POST["correo"];
    $P = $_POST["password"];


    //Evitar inyección de código
    $correo = htmlspecialchars($E);
    $password = htmlspecialchars($P);

    //Encriptamos password
    $encrip = password_hash($password, PASSWORD_DEFAULT);

    //Conexión BD
    $mysqli = mysqli_connect($server,$user,$pass,$bd);

    //Consulta SQL (SELECT). Comprobamos si el email ya existe
    $sqlSelect = "SELECT * FROM Usuario WHERE Correo = '".$correo."'" ;
    $result = mysqli_query($mysqli, $sqlSelect);

    //Comprobar resultado
    if (mysqli_num_rows($result) == 1) {
        $sqlUpdate = "UPDATE Usuario SET Password = '".$encrip."' WHERE Correo = '".$correo."'";

        $result2 = mysqli_query($mysqli,$sqlUpdate);

        if(mysqli_connect_errno()==0){
            //Consulta correcta
            $response["success"] = 1;
            $response["message"] = "Update realizado con exito";


        }else{
            $response["success"] = 0;
            $response["message"] = "Fallo en el update";

            //Mostramos respuesta JSON
        echo json_encode($response);
        }



    }else if(mysqli_num_rows($result) == 0){
        //Consulta incorrecta
        $response["success"] = 0;
        $response["message"] = "No existe un usuario con ese correo";

    //Mostramos respuesta JSON
    echo json_encode($response);
    }else{
        //Consulta incorrecta
        $response["success"] = 0;
        $response["message"] = "Hay mas de un usuario con ese correo.";

    //Mostramos respuesta JSON
        echo json_encode($response);
    }
}else{
    //Consulta incorrecta
    $response["success"] = 0;
    $response["message"] = "Error.Campo vacio";

    //Mostramos respuesta JSON
    echo json_encode($response);
}



?>

package com.example.alex.proyecto;

public class UpdatePass {

/**
 * success : 0
 * message : Error.Campo vacio
 */

private int success;
private String message;

public int getSuccess() {
    return success;
}

public void setSuccess(int success) {
    this.success = success;
}

public String getMessage() {
    return message;
}

public void setMessage(String message) {
    this.message = message;
}

package com.example.alex.proyecto;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.google.gson.Gson;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.JsonHttpResponseHandler;
import com.loopj.android.http.RequestParams;

import org.json.JSONObject;

import cz.msebera.android.httpclient.Header;

public class CambioPassActivity extends AppCompatActivity {
EditText pass,pass2;
Button bCambiar;
String correoN;
String url = "ftp://proyectokiriki@files.000webhost.com/public_html/cambiarPass.php";

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


    pass = (EditText) findViewById(R.id.textoPass);
    pass2 = (EditText) findViewById(R.id.textoPass2);
    bCambiar = (Button) findViewById(R.id.botonCambioPass);
    correoN = getIntent().getStringExtra("correo");

    bCambiar.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(getApplicationContext(), correoN, Toast.LENGTH_LONG).show();

            if(pass.getText().toString().trim().equalsIgnoreCase("")||pass2.getText().toString().trim().equalsIgnoreCase("")){
                LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                final View formElementsView = inflater.inflate(R.layout.pantalla_jugadores,
                        null, false);

                AlertDialog.Builder builder = new AlertDialog.Builder(CambioPassActivity.this);
                builder.setTitle("Deben estar todos los campos rellenos.");
                builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface dialog, int id) {
                        dialog.dismiss();
                    }
                });
                builder.setView(formElementsView);
                final AlertDialog dialog = builder.create();
                dialog.show();
            }else{

                if(pass.getText().toString().trim().equalsIgnoreCase(pass2.getText().toString().trim())==true) {
                    AsyncHttpClient cliente = new AsyncHttpClient();
                    RequestParams rp = new RequestParams();
                    rp.put("correo", correoN);
                    rp.put("password", pass.getText().toString().trim());

                    cliente.post(url, rp, new JsonHttpResponseHandler() {
                        @Override
                        public void onSuccess(int statusCode, Header[] headers, JSONObject response) {

                            if (statusCode == 200) {

                                String respuesta = response.toString();
                                Gson gson = new Gson();

                                UpdatePass update = gson.fromJson(respuesta, UpdatePass.class);

                                String mensaje = update.getMessage();
                                Toast.makeText(getApplicationContext(), mensaje, Toast.LENGTH_LONG).show();
                                int res = update.getSuccess();

                                //Si es correcta
                                if (res == 1) {
                                    Toast.makeText(getApplicationContext(), "Contraseña cambiada", Toast.LENGTH_LONG).show();
                                    //Una vez iniciada la sesión, nos vamos a la pantalla principal

                                    Intent Principal = new Intent(getApplicationContext(), MainActivity.class);
                                    finish();
                                    startActivity(Principal);

                                }
                            }
                        }
                    });
                }
            }
        }
    });

}
}