Eu sou novato no desenvolvimento do Android. Estou usando o Android Studio. Estou criando um aplicativo no qual há uma lista suspensa de nomes. Ao selecionar qualquer nome, o correspondenteID desse nome é mostrado no aplicativo. Depois, há um botão que pesquisa as coordenadas GPS atuais do usuário e as mostra no aplicativo. Procurei perguntas semelhantes e encontrei alguns links (eu os publicarei no final), mas não consegui entendê-los. Abaixo está a captura de tela do aplicativo

Eu tenho duas tabelas no mysql;users eactivity, como mostrado abaixo

Comercial

Atividade

oUserId é a chave estrangeira na tabela de atividades, ou seja, oId deusers tabela será inserida nela.

Eu criei o seguinte script para retornar os dados como JSON:

<?php
    require_once ('config.php');

    $sql = "SELECT * FROM users";  
    $r = mysqli_query($con,$sql); 
    $result = array();

    while($row = mysqli_fetch_array($r)){
        array_push($result,array(
            'Id'=>$row['Id'],
            'Name'=>$row['Name']
        )); 
      }//end while

    echo json_encode(array('users'=>$result));

    mysqli_close($con);
?>

No código do meu aplicativo, criei umusers classe

Classe Usuários

public class Users {

private String Id;
private String Name;

public String getId() {
    return Id;
}

public void setId(String id) {
    this.Id = id;
}

public String getName() {
    return Name;
}

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

CLASSE JSON

public class JSONfunctions {


public static JSONObject getJSONfromURL(String url)
{

    String json = "";
    JSONObject jsonObject = null;
    try
    {
        HttpClient httpClientt = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        HttpResponse httpResponse = httpClientt.execute(httpGet);
        BufferedReader br = new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent()));
        StringBuffer sb = new StringBuffer();
        String line = "";
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }

        json = sb.toString();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try
    {
        jsonObject = new JSONObject(json);
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return jsonObject;
}

Atividade principal

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

    _latitude = (TextView)findViewById(R.id.latitude);
    _longitude = (TextView)findViewById(R.id.longitude);
    btn_get_coordinates = (Button)findViewById(R.id.button);




    final PermissionListener permissionlistener = new PermissionListener() {
        @Override
        public void onPermissionGranted() {
            //Toast.makeText(MainActivity.this, "Permission Granted", Toast.LENGTH_SHORT).show();

            buildGoogleApiClient();
            //checkLocation(); //check whether location service is enable or not in your  phone
        }

        @Override
        public void onPermissionDenied(ArrayList<String> deniedPermissions) {
            Toast.makeText(MainActivity.this, "Permission Denied\n" + deniedPermissions.toString(), Toast.LENGTH_SHORT).show();
        }
    };

    btn_get_coordinates.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


            new TedPermission(MainActivity.this)
                    .setPermissionListener(permissionlistener)
                    .setRationaleMessage("This app needs Permission to find your location")
                    .setPermissions(Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION)
                    .check();


        }
    });

    // Download JSON file AsyncTask
    new DownloadJSON().execute();
}

/////////////////////////////////////// Start of Location Services ///////////////////////////////////////////////////////

protected synchronized  void buildGoogleApiClient() {

    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build();

    if (mGoogleApiClient != null) {
        mGoogleApiClient.connect();
    } else
        Toast.makeText(this, "Not Connected!", Toast.LENGTH_SHORT).show();

}


/*Ending the updates for the location service*/
@Override
protected void onStop() {
    mGoogleApiClient.disconnect();
    super.onStop();
}

@Override
public void onConnected(@Nullable Bundle bundle) {
    settingRequest();
}

@Override
public void onConnectionSuspended(int i) {
    Toast.makeText(this, "Connection Suspended!", Toast.LENGTH_SHORT).show();
}

@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
    Toast.makeText(this, "Connection Failed!", Toast.LENGTH_SHORT).show();
    if (connectionResult.hasResolution()) {
        try {
            // Start an Activity that tries to resolve the error
            connectionResult.startResolutionForResult(this, 90000);
        } catch (IntentSender.SendIntentException e) {
            e.printStackTrace();
        }
    } else {
        Log.i("Current Location", "Location services connection failed with code " + connectionResult.getErrorCode());
    }
}


/*Method to get the enable location settings dialog*/
public void settingRequest() {
    mLocationRequest = new LocationRequest();
    mLocationRequest.setInterval(10000);    // 10 seconds, in milliseconds
    mLocationRequest.setFastestInterval(1000);   // 1 second, in milliseconds
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

    LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder()
            .addLocationRequest(mLocationRequest);

    PendingResult<LocationSettingsResult> result =
            LocationServices.SettingsApi.checkLocationSettings(mGoogleApiClient,
                    builder.build());

    result.setResultCallback(new ResultCallback<LocationSettingsResult>() {

        @Override
        public void onResult(@NonNull LocationSettingsResult result) {
            final Status status = result.getStatus();
            final LocationSettingsStates state = result.getLocationSettingsStates();
            switch (status.getStatusCode()) {
                case LocationSettingsStatusCodes.SUCCESS:
                    // All location settings are satisfied. The client can
                    // initialize location requests here.
                    getLocation();
                    break;
                case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
                    // Location settings are not satisfied, but this can be fixed
                    // by showing the user a dialog.
                    try {
                        // Show the dialog by calling startResolutionForResult(),
                        // and check the result in onActivityResult().
                        status.startResolutionForResult(MainActivity.this, 1000);
                    } catch (IntentSender.SendIntentException e) {
                        // Ignore the error.
                    }
                    break;
                case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
                    // Location settings are not satisfied. However, we have no way
                    // to fix the settings so we won't show the dialog.
                    break;
            }
        }

    });
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    final LocationSettingsStates states = LocationSettingsStates.fromIntent(data);
    switch (requestCode) {
        case 1000:
            switch (resultCode) {
                case Activity.RESULT_OK:
                    // All required changes were successfully made
                    getLocation();
                    break;
                case Activity.RESULT_CANCELED:
                    // The user was asked to change settings, but chose not to
                    Toast.makeText(this, "Location Service not Enabled", Toast.LENGTH_SHORT).show();
                    break;
                default:
                    break;
            }
            break;
    }
}


public void getLocation() {
    if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        // TODO: Consider calling
        //    ActivityCompat#requestPermissions
        // here to request the missing permissions, and then overriding
        //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
        //                                          int[] grantResults)
        // to handle the case where the user grants the permission. See the documentation
        // for ActivityCompat#requestPermissions for more details.
        return;
    } else {
        /*Getting the location after aquiring location service*/
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient);

        if (mLastLocation != null) {
           // _progressBar.setVisibility(View.INVISIBLE);
            _latitude.setText("Latitude: " + String.valueOf(mLastLocation.getLatitude()));
            _longitude.setText("Longitude: " + String.valueOf(mLastLocation.getLongitude()));
        } else {
            /*if there is no last known location. Which means the device has no data for the loction currently.
            * So we will get the current location.
            * For this we'll implement Location Listener and override onLocationChanged*/
            Log.i("Current Location", "No data for location found");

            if (!mGoogleApiClient.isConnected())
                mGoogleApiClient.connect();

            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, MainActivity.this);
        }
    }
}



@Override
public void onLocationChanged(Location location) {

    mLastLocation = location;
    _progressBar.setVisibility(View.INVISIBLE);
    _latitude.setText("Latitude: " + String.valueOf(mLastLocation.getLatitude()));
    _longitude.setText("Longitude: " + String.valueOf(mLastLocation.getLongitude()));

}

//////////////////////////////////////////// End of Location services ///////////////////////////////////////////////


////////////////////////////////////////// Start of getting JSON DATA ///////////////////////////////////////////////

// Download JSON file AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void>
{

   /* @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog = new ProgressDialog(MainActivity.this);
        progressDialog.setMessage("Fetching Users....!");
        progressDialog.setCancelable(false);
        progressDialog.show();

    }*/

    @Override
    protected Void doInBackground(Void... params) {

        // Locate the Users Class
        users = new ArrayList<Users>();

        // Create an array to populate the spinner
        userList = new ArrayList<String>();
        // http://10.0.2.2:8000/MobileApp/index.php
        //http://10.0.2.2:8000/app/web/users/
        //http://192.168.100.8:8000/app/web/users/
        // JSON file URL address
        jsonObject = JSONfunctions.getJSONfromURL("http://192.168.100.15:8000/MobileApp/GET_DATA.php");

        try
        {
            JSONObject jobj = new JSONObject(jsonObject.toString());
            // Locate the NodeList name
            jsonArray = jobj.getJSONArray("users");

            for(int i=0; i<jsonArray.length(); i++)
            {
                jsonObject = jsonArray.getJSONObject(i);

                Users user = new Users();

                user.setId(jsonObject.optString("Id"));
                user.setName(jsonObject.optString("Name"));
                users.add(user);

                userList.add(jsonObject.optString("Name"));

            }
        } catch (JSONException e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }


        return null;
    }

    @Override
    protected void onPostExecute(Void args)
    {
        // Locate the spinner in activity_main.xml
        Spinner spinner = (Spinner)findViewById(R.id.spinner);

        // Spinner adapter
        spinner.setAdapter(new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_spinner_dropdown_item, userList));

        // Spinner on item click listener

        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

                textViewResult = (TextView)findViewById(R.id.textView);

                // Set the text followed by the position

                textViewResult.setText("Hi " + users.get(position).getName() + " your ID is " + users.get(position).getId());

            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                textViewResult.setText("");
            }
        });
    }


}
//////////////////////////////////////// End of getting JSON DATA //////////////////////////////////////////

Ao pressionar o botão Salvar, os seguintes campos serão inseridos noActivity mesa

Id (Que é incremento automático)UserId (ID do usuário da tabela Usuários com base no nome selecionado)Latitude (Do usuário atual)Longitude (Do usuário atual)DateTime (Data e hora do usuário)

Devo ter que criar uma classe de 'atividade' como eu criei oUser classe?

Para isso, tenho algo em mente

Eu salvaria os dados emxml outxt primeiro, então ele será salvo no banco de dados.Eu deveria converter os dados emjson formate e salve-o no DBSalve-o diretamente no banco de dados usando uma consulta no meuphp roteiro

Qual destes três é mais fácil de implementar? Seria muito útil se alguém pudesse me fornecer um tutorial, embora eu tenha visto muitos deles (1 , 2 ) e, como descrito acima, eu não os entendia :(.

Estou preso a isso e não sei o que tenho que fazer. Qualquer ajuda seria muito apreciada.