How to migrate a web page to an Android app

First of all, I am new to Android, and I want to clarify that I have already investigated and searched for tutorials, what I intend to do is, solely and exclusively, that information can be saved in an Android application through a form which contains: EditTextand Spinners. It should be clarified that I have already done this on a web page, but now I want to create the application that performs the same function, that is, save.

I also want to clarify that I have already done this before in java, but I have been searching the Internet for days and days and I can't find any similar example. Also, from the little I have found, I have tried to adapt it to what I need and nothing. Is what I want to do very complicated or is it more difficult to do this kind of thing in Android?

Well, I don't want them to do the project for me, but could someone guide me on what I need to do?

After researching your advice I decided to try doing it natively and so far I have the following but I am having trouble saving the date formats and I have no idea how to save thespinners

I attach the image of my form (the button that saves says next because I still intend to make some changes)

The xml of the image above is as follows:

    <?xml version="1.0" encoding="utf-8"?>
<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.server.guardar_a.MainActivity">

    <ScrollView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/scrollView">
        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">

            <Spinner
                android:layout_width="140dp"
                android:layout_height="wrap_content"
                android:id="@+id/sp_tiempodeuso"
                android:focusable="true"
                android:layout_below="@+id/txtv_tiempouso"
                android:layout_alignParentLeft="true"
                android:layout_alignParentStart="true" />

            <TextView
                android:layout_width="140dp"
                android:layout_height="30dp"
                android:text="Tiempo de uso:"
                android:textColor="#000000"
                android:textSize="20sp"
                android:id="@+id/txtv_tiempouso"
                android:layout_alignTop="@+id/txtv_docente" />

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="time"
                android:ems="10"
                android:hint="Hora de Inicio"
                android:textColorHint="#424242"
                android:id="@+id/txt_horainicio"
                android:imeOptions="actionNext"
                android:layout_below="@+id/txt_fechadeuso"
                android:layout_alignParentLeft="true"
                android:layout_alignParentStart="true"
                android:layout_marginTop="18dp" />

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="none"
                android:descendantFocusability="blocksDescendants"
                android:ems="10"
                android:hint="Fecha de uso"
                android:textColorHint="#424242"
                android:nextFocusDown="@+id/txt_horainicio"
                android:id="@+id/txt_fechadeuso"
                android:imeOptions="actionNext"
                android:layout_below="@+id/txt_practica"
                android:layout_alignParentRight="true"
                android:layout_alignParentEnd="true"
                android:layout_marginTop="16dp"
                android:onClick="mostrarCalendario" />

            <Spinner
                android:layout_width="140dp"
                android:layout_height="wrap_content"
                android:id="@+id/sp_docente"
                android:focusable="true"
                android:focusableInTouchMode="true"
                android:layout_alignBaseline="@+id/sp_tiempodeuso"
                android:layout_alignBottom="@+id/sp_tiempodeuso"
                android:layout_alignParentRight="true"
                android:layout_alignParentEnd="true" />

            <TextView
                android:layout_width="130dp"
                android:layout_height="30dp"
                android:text="Docente:"
                android:textColor="#000000"
                android:id="@+id/txtv_docente"
                android:textSize="20sp"
                android:layout_marginTop="31dp"
                android:layout_below="@+id/txt_horainicio"
                android:layout_alignParentRight="true"
                android:layout_alignParentEnd="true" />

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textPersonName"
                android:ems="10"
                android:id="@+id/txt_practica"
                android:hint="Practica"
                android:textColorHint="#424242"
                android:layout_marginTop="9dp"
                android:layout_alignParentLeft="true"
                android:layout_alignParentStart="true" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="fill_parent"
                android:text="Siguiente"
                android:textSize="20sp"
                android:id="@+id/btn_form1"
                android:layout_below="@+id/sp_tiempodeuso"
                android:layout_alignParentLeft="true"
                android:layout_alignParentStart="true"
                android:layout_marginTop="41dp"/>

        </RelativeLayout>

    </ScrollView>


</RelativeLayout>

My JSONParser class

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    public JSONParser(){
    }

    public JSONObject getJSONFromUrl(final String url){

        try {
            DefaultHttpClient httpClient = new DefaultHttpClient();

            HttpPost httpPost = new HttpPost(url);

            HttpResponse httpResponse = httpClient.execute(httpPost);

            HttpEntity httpEntity = httpResponse.getEntity();

            is = httpEntity.getContent();
        }catch (UnsupportedEncodingException e){
            e.printStackTrace();
        }catch (ClientProtocolException e){
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);

            StringBuilder sb = new StringBuilder();

            String line = null;

            while ((line = reader.readLine()) != null){
                sb.append(line+"\n");
            }
            is.close();

            json = sb.toString();
        }catch (Exception e){
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }
        return jObj;
    }


    public JSONObject makeHttpRequest(String url, String method,
                                      List params){

        try{
            if(method == "POST"){
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }else if(method == "GET"){

                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params,"utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }
        }catch (UnsupportedEncodingException e){
            e.printStackTrace();
        }catch (ClientProtocolException e){
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }

        try{
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;

            while ((line = reader.readLine()) != null){
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        }catch (Exception e){
            Log.e("Buffer Error","Error converting result"+e.toString());
        }

        try{
            jObj = new JSONObject(json);
        }catch (JSONException e){
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }
        return jObj;
    }
}

And my MainActivity

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private EditText practica, fechauso, horainicio;
    private Button botonform1;
    Spinner n_docentes, t_uso;
    private int anio, dia, mes, hora, minuto;
    private static final int TIPO_DIALOGO=0;
    private static DatePickerDialog.OnDateSetListener oyenteSelectorFecha;

    private ProgressDialog pDialog;

    JSONParser jsonParser = new JSONParser();

    private static final String REGISTER_URL = "http://wservervv.esy.es/laboratorio/guardar_solicitud.php";

    private static final String TAG_SUCCESS = "success";
    private static final String TAG_MESSAGE = "message";

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

            practica = (EditText)findViewById(R.id.txt_practica);
            fechauso = (EditText)findViewById(R.id.txt_fechadeuso);
            horainicio = (EditText)findViewById(R.id.txt_horainicio);
    //        t_uso = (Spinner)findViewById(R.id.sp_tiempodeuso);
    //        n_docentes = (Spinner)findViewById(R.id.sp_docente);
            botonform1 = (Button)findViewById(R.id.btn_form1);
            botonform1.setOnClickListener(this);

        fechauso.setInputType(InputType.TYPE_NULL);

        ArrayAdapter adapter_d = ArrayAdapter.createFromResource(this, R.array.Nombres_Docentes, R.layout.spiner_item_lab);
        n_docentes.setAdapter(adapter_d);
        ArrayAdapter adapter_t = ArrayAdapter.createFromResource(this, R.array.Tiempo_Uso, R.layout.spiner_item_lab);
        t_uso.setAdapter(adapter_t);

        Calendar calendario = Calendar.getInstance();
        anio = calendario.get(Calendar.YEAR);mes = calendario.get(Calendar.MONTH);dia = calendario.get(Calendar.DAY_OF_MONTH);

        oyenteSelectorFecha = new DatePickerDialog.OnDateSetListener() {
            @Override
            public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                anio = year;mes = monthOfYear;dia = dayOfMonth;mostrarFecha();
           /*     try {
                    Thread.sleep (5000);
                } catch (Exception e) {
                // Mensaje en caso de que falle
                }   */
                horainicio.requestFocus();
            }
        };

        fechauso.setOnFocusChangeListener(new View.OnFocusChangeListener() {

            public void onFocusChange(View v, boolean hasFocus) {
                //Si tiene el Foco esconde el teclado y muestra el datePicker
                if(hasFocus){
                    closeSoftKeyBoard();mostrarCalendario(fechauso);
                }
            }
        });

        horainicio.setOnFocusChangeListener(new View.OnFocusChangeListener() {

            public void onFocusChange(View v, boolean hasFocus) {
                //Si tiene el Foco Esconde el teclado y muestra el timePicker
                if(hasFocus){
                    closeSoftKeyBoard();
                    mostrarTime();
                }
            }
        });
            }


    @Override
    public void onClick(View args0) {
        if(args0 == horainicio){
            closeSoftKeyBoard();
            mostrarTime();
        }
        if(args0 == botonform1) {
            String practicaa = practica.getText().toString();
            String fechausoo = fechauso.getText().toString();
            String horainicioo = horainicio.getText().toString();
            //        String t_usoo = t_uso.getText().toString();
            //        String n_docentess = n_docentes.getText().toString();
            new CreateUser().execute(practicaa, fechausoo, horainicioo);
         }
        }

    class CreateUser extends AsyncTask<String, String, String> {

        protected void onPreExecute(){
            super.onPreExecute();
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Guardando.....");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        @Override
        protected String doInBackground(String... args) {
            // Todo Auto-generated method stub
            // Check for success tag
            int success;
            String practicaa = args[0];
            String fechausoo = args[1];
            String horainicioo = args[2];
//            String t_usoo = args[3];
//            String n_docentess = args[4];

            try{
                List params = new ArrayList();
                params.add(new BasicNameValuePair("practica", practicaa));
                params.add(new BasicNameValuePair("fecha_prestamo", fechausoo));
                params.add(new BasicNameValuePair("hora_prestamo", horainicioo));
//                params.add(new BasicNameValuePair("horas_uso", t_usoo));
//                params.add(new BasicNameValuePair("idusuario", n_docentess));

                Log.d("request!", "starting");

                JSONObject json = jsonParser.makeHttpRequest(
                        REGISTER_URL, "POST", params);

                Log.d("Registering attempt", json.toString());

                success = json.getInt(TAG_SUCCESS);
                if(success == 1){
                    Log.d("User Created!", json.toString());
                    finish();
                    return json.getString(TAG_MESSAGE);
                }else{
                    Log.d("Registering Failure!", json.getString(TAG_MESSAGE));
                    return json.getString(TAG_MESSAGE);
                }
            }catch (JSONException e){
                e.printStackTrace();
            }
            Toast.makeText(getApplicationContext(),"Usuario guardado con exito... ",Toast.LENGTH_LONG).show();
            return null;
        }

        protected void onPostExecute(String file_url){

            pDialog.dismiss();
            if (file_url != null){
                Toast.makeText(MainActivity.this, file_url, Toast.LENGTH_LONG).show();
            }
        }

    }

    public void mostrarTime(){
        // Get Current Time
        final Calendar c = Calendar.getInstance();
        hora = c.get(Calendar.HOUR);
        minuto = c.get(Calendar.MINUTE);

        TimePickerDialog timePickerDialog = new TimePickerDialog(this,
                new TimePickerDialog.OnTimeSetListener() {

                    @Override
                    public void onTimeSet(TimePicker view, int hourOfDay,
                                          int minute) {

                        horainicio.setText(hourOfDay + ":" + minute+":00");
                     //   t_uso.requestFocus();
                    }
                }, hora, minuto, false);
        timePickerDialog.show();
    }

    public void closeSoftKeyBoard() {
        InputMethodManager inputMethodManager = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
        inputMethodManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id){
            case 0:
                return new DatePickerDialog(this, oyenteSelectorFecha, anio, mes, dia);
        }
        return null;
    }

    public void mostrarCalendario(View control){
        showDialog(TIPO_DIALOGO);
    }

    public void mostrarFecha(){
        fechauso.setText(anio+"-"+(mes+1)+"-"+dia);
    }
}

The strings.xml

<resources>
    <string name="app_name">Guardar_A</string>

    <!-- Spinner docentes  -->
    <string-array name="Nombres_Docentes">
        <item>Seleccione</item>
        <item>Juan</item>
        <item>Pedro</item>
        <item>Jose</item>
    </string-array>

    <!-- Spinner tiempo de uso  -->
    <string-array name="Tiempo_Uso">
        <item>Seleccione</item>
        <item>1 Hora</item>
        <item>2 Horas</item>
        <item>3 Horas</item>
    </string-array>

</resources>

My loan table :

my php files:

db_config.php

<?php
define('DB_USER',"u557976579_swgvv");
define('DB_PASSWORD',"guardar_a");
define('DB_DATABASE',"u557976579_bdser");
define('DB_SERVER',"mysql.hostinger.mx");
?>

db_connect.php

<?php

class DB_CONNECT {

    function __construct(){
        $this->connect();
    }

    function __destruct(){
        $this->close();
    }


    function connect(){

    require_once __DIR__ . '/db_config.php';

    $con = @mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) or die(mysql_error());

    $db = @mysql_select_db(DB_DATABASE) or die(mysql_error()) or die(mysql_error());

    return $con;
    }

    function close(){

        mysql_close();
    }

  }
?>

save_request.php

guardar_solicitud.php
<?php

$response = array();

//if (isset($_POST['idusario']) && isset($_POST['fecha_prestamo']) && isset($_POST['hora_prestamo']) && isset($_POST['horas_uso']) && isset($_POST['practica']) && isset($_POST['idusuariosolicitud'])){
if (isset($_POST['fecha_prestamo']) && isset($_POST['hora_prestamo']) && isset($_POST['practica'])){
    $nombredocente = 4;
    $fechauso = $_POST['fechauso'];
    $horainicio = $_POST['horainicio'];
    $timeuso = 1;
    $practica = $_POST['practica'];
    $usuariosolicitud=1;

    require_once __DIR__ . '/db_connect.php';

    $db = new DB_CONNECT();

    $result = mysql_query("INSERT INTO prestamo(idusuario,fecha_prestamo,hora_prestamo,horas_uso,practica,idusuariosolicitud) VALUES('$nombredocente', '$fechauso', '$horainicio', '$timeuso','$practica', '$usuarioquesolicita')");

    if ($result){

        $response["success"] = 1;
        $response["message"] = "Product successfully created.";

        echo json_encode($response);
    }else{

        $response["success"] = 0;
        $response["message"] = "Oops! An error ocurred.";       

        echo json_encode($response);
    }
}else{

        $response["success"] = 0;
        $response["message"] = "Required field(s) is missing";      

        echo json_encode($response);

}

?>

That's what I have so far