keep data from a recycler view when exiting and reopening the shared preferences app

0

Hello, how are your colleagues? My question is how do I keep the session and the data of a recycler view within an activity? I have tried with sharedprefrences and it brings me the data that I store, but not the necessary data for the recycler view and does not return anything this happens when leaving and re-entering the app the shared preferences returns me the data I want but in the recycler view loses the data and does not return anything as I do so that it also maintains the reclyver view data ie that by the time I leave and open the app again I keep the data from the recycler view, it should be noted that the main idea is to have created a button to keep session in the class to log in to recover the data in the other classes and keep the session of a user open in all the application when it leaves and returns to enter the app the truth would be thank you very many friends I hope you can help me.

Login.java

public class Login extends AppCompatActivity {


// Creating EditText.
EditText Email, Password;

// Creating button;
Button LoginButton;

// Creating Volley RequestQueue.
RequestQueue requestQueue;

// Create string variable to hold the EditText Value.
String EmailHolder, PasswordHolder,md1,md2;

// Creating Progress dialog.
ProgressDialog progressDialog;

// Storing server url into String variable.

String HttpUrl = "xxxxxxxxxxxxxx";

Boolean CheckEditText;

TextView tv_register;

private RadioButton RBsesion;

private boolean isActivateRadioButton;

String ServerResponse = null ;

String TempServerResponseMatchedValue = "returnState" ;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);
    initialize(); //Initialize all the widgets present in the layout

    if(Preferences.obtenerPreferenceBoolean(this,Preferences.PREFERENCE_ESTADO_BUTTON_SESION)){
        Intent i = new Intent(Login.this,Principal.class);
        startActivity(i);
        finish();
    }

    Email = (EditText) findViewById(R.id.editText_Email);

    Password = (EditText) findViewById(R.id.editText_Password);

    LoginButton = (Button) findViewById(R.id.bt_login);

    RBsesion = (RadioButton) findViewById(R.id.RBSecion);

    requestQueue = Volley.newRequestQueue(Login.this);

    progressDialog = new ProgressDialog(Login.this);

    isActivateRadioButton = RBsesion.isChecked(); //DESACTIVADO

    RBsesion.setOnClickListener(new View.OnClickListener() {
        //ACTIVADO
        @Override
        public void onClick(View v) {
            if(isActivateRadioButton){
                RBsesion.setChecked(false);
            }
            isActivateRadioButton = RBsesion.isChecked();
        }
    });

    LoginButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            CheckEditTextIsEmptyOrNot();

            if (CheckEditText) {

                UserLogin();

            } else {

                Toast.makeText(Login.this, "Please fill all form fields.", Toast.LENGTH_LONG).show();

            }

        }
    });

}

private void initialize() {
    tv_register = (TextView) findViewById(R.id.tv_register);
}


public void UserLogin() {

    progressDialog.setMessage("Please Wait");
    progressDialog.show();

    StringRequest stringRequest = new StringRequest(Request.Method.POST, HttpUrl,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String ServerResponse) {

                    progressDialog.dismiss();


                    try{
                        JSONObject jsonObject = new JSONObject(ServerResponse);

                        String returnState= jsonObject.getString("returnState");
                        String returnData= jsonObject.getString("returnData");

                        if(returnData=="null"){
                            Toast.makeText(Login.this, "Incorrect user or password", Toast.LENGTH_LONG).show();
                        }else{

                            JSONObject jsonObjecto= new JSONObject(returnData);
                            String gys= jsonObjecto.getString("gys");

                            JSONObject jsonObjectogys= new JSONObject(gys);
                            String seller_id=jsonObjectogys.getString("seller_id");
                            String shop_id=jsonObjectogys.getString("shop_id");
                            JSONObject jsonObjectData= new JSONObject(returnData);

                            Preferences.savePreferenceBoolean(Login.this,RBsesion.isChecked(),Preferences.PREFERENCE_ESTADO_BUTTON_SESION);
                            Preferences.savePreferendceString(Login.this,EmailHolder, PREFERENCE_USUARIO_LOGIN);
                            Preferences.savePreferendceString(Login.this,seller_id, PREFERENCE_SELLER_ID);
                            Preferences.savePreferendceString(Login.this,shop_id, PREFERENCE_SHOP_ID);

                            Intent intent = new Intent(Login.this, Principal.class);
                            Toast.makeText(getBaseContext(),"Successful session start", Toast.LENGTH_LONG).show();
                            intent.putExtra("UserEmailTAG",EmailHolder);
                            intent.putExtra("password",md1);
                            intent.putExtra("seller_id",seller_id);
                            intent.putExtra("shop_id",shop_id);


                            Toast.makeText(getBaseContext(),"Successful session start", Toast.LENGTH_LONG).show();
                            startActivity(intent);

                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }


                }
            }
            ,
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError volleyError) {

                    // Hiding the progress dialog after all task complete.
                    progressDialog.dismiss();

                    Toast.makeText(Login.this,"Need internet access", Toast.LENGTH_LONG).show();
                }
            }) {
        @Override
        protected Map<String, String> getParams() {

            // Creating Map String Params.
            Map<String, String> params = new HashMap<String, String>();

            // Adding All values to Params.
            // The firs argument should be same sa your MySQL database table columns.
            params.put("username", EmailHolder);
            params.put("password", md1);

            return params;
        }

    };

    // Creating RequestQueue.
    RequestQueue requestQueue = Volley.newRequestQueue(Login.this);

    // Adding the StringRequest object into requestQueue.
    requestQueue.add(stringRequest);

}

Principal.java (Main menu)

public class Principal extends AppCompatActivity {

TextView pedido,fecha2,fecha1;
Button logout;
NetworkImageView networkImageView;
ImageLoader imageLoader;
RequestQueue requestQueue;
String xnombre,fech1,fech2;
Calendar calendario= Calendar.getInstance();
Spinner sexo;

private Button cerrarSesion;

private String EMISOR = "";
private String EMISOR2 = "";
private String EMISOR3 = "";

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

    EMISOR = Preferences.obtenerPreferenceString(this,Preferences.PREFERENCE_USUARIO_LOGIN);
    EMISOR2 = Preferences.obtenerPreferenceString(this,Preferences.PREFERENCE_SELLER_ID);
    EMISOR3 = Preferences.obtenerPreferenceString(this,Preferences.PREFERENCE_SHOP_ID);

    Toast.makeText(this, EMISOR, Toast.LENGTH_SHORT).show();
    Toast.makeText(this, EMISOR2, Toast.LENGTH_SHORT).show();
    Toast.makeText(this, EMISOR3, Toast.LENGTH_SHORT).show();

    showDatePickerDialog();
    showDatePickerDialog2();
    showDatePickerDialog3();
    showDatePickerDialog4();

    cerrarSesion = (Button) findViewById(R.id.cerrarSesion);

    cerrarSesion.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Preferences.savePreferenceBoolean(Principal.this,false,Preferences.PREFERENCE_ESTADO_BUTTON_SESION);
            Toast.makeText(Principal.this, "Logged Out Successfully", Toast.LENGTH_LONG).show();
            // finish();
            Intent i = new Intent(Principal.this,Login.class);
            startActivity(i);
            finish();
        }
    });
}


private void actualizarInput() {
    String formatoDeFecha = "yyyy.MM.dd";
    SimpleDateFormat sdf = new SimpleDateFormat(formatoDeFecha, Locale.US);
    fecha1.setText(sdf.format(calendario.getTime()));
}


DatePickerDialog.OnDateSetListener date = new DatePickerDialog.OnDateSetListener() {

    @Override
    public void onDateSet(DatePicker view, int year, int monthOfYear,
                          int dayOfMonth) {
        // TODO Auto-generated method stub
        calendario.set(Calendar.YEAR, year);
        calendario.set(Calendar.MONTH, monthOfYear);
        calendario.set(Calendar.DAY_OF_MONTH, dayOfMonth);
        actualizarInput();
    }

};

private void showDatePickerDialog2()
{
    // Get open DatePickerDialog button.
    TextView datePickerDialogButton =(TextView) findViewById(R.id.fecha2);
    datePickerDialogButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Create a new OnDateSetListener instance. This listener will be invoked when user click ok button in DatePickerDialog.
            DatePickerDialog.OnDateSetListener onDateSetListener = new DatePickerDialog.OnDateSetListener() {
                @Override
                public void onDateSet(DatePicker datePicker, int year, int month, int dayOfMonth) {
                    StringBuffer strBuf = new StringBuffer();
                    //   strBuf.append("");
                    strBuf.append(year);
                    strBuf.append(".");
                    strBuf.append(month+1);
                    strBuf.append(".");
                    strBuf.append(dayOfMonth);

                    TextView datePickerValueTextView = (TextView)findViewById(R.id.fecha2);
                    datePickerValueTextView.setText(strBuf.toString());
                }
            };

            // Get current year, month and day.
            Calendar now = Calendar.getInstance();
            int year = now.get(java.util.Calendar.YEAR);
            int month = now.get(java.util.Calendar.MONTH);
            int day = now.get(java.util.Calendar.DAY_OF_MONTH);

            // Create the new DatePickerDialog instance.
            DatePickerDialog datePickerDialog = new DatePickerDialog(Principal.this, android.R.style.Theme_Holo_Light_Dialog, onDateSetListener, year, month, day);
            datePickerDialog.getWindow().setBackgroundDrawableResource(R.color.transparent);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_POSITIVE, "确定", datePickerDialog);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_NEGATIVE, "取消", (DialogInterface.OnClickListener)null);


            // datePickerDialog.setIcon(R.drawable.ic_001_busqueda);
            datePickerDialog.setTitle("月                      日                     年");

            // Popup the dialog.
            datePickerDialog.show();
        }
    });
}

private void showDatePickerDialog()
{
    // Get open DatePickerDialog button.
    TextView datePickerDialogButton =(TextView) findViewById(R.id.fecha1);
    datePickerDialogButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Create a new OnDateSetListener instance. This listener will be invoked when user click ok button in DatePickerDialog.
            DatePickerDialog.OnDateSetListener onDateSetListener = new DatePickerDialog.OnDateSetListener() {
                @Override
                public void onDateSet(DatePicker datePicker, int year, int month, int dayOfMonth) {
                    StringBuffer strBuf = new StringBuffer();
                    //   strBuf.append("");
                    strBuf.append(year);
                    strBuf.append(".");
                    strBuf.append(month+1);
                    strBuf.append(".");
                    strBuf.append(dayOfMonth);

                    TextView datePickerValueTextView = (TextView)findViewById(R.id.fecha1);
                    datePickerValueTextView.setText(strBuf.toString());
                }
            };

            // Get current year, month and day.
            Calendar now = Calendar.getInstance();
            int year = now.get(java.util.Calendar.YEAR);
            int month = now.get(java.util.Calendar.MONTH);
            int day = now.get(java.util.Calendar.DAY_OF_MONTH);

            // Create the new DatePickerDialog instance.
            DatePickerDialog datePickerDialog = new DatePickerDialog(Principal.this, android.R.style.Theme_Holo_Light_Dialog, onDateSetListener, year, month, day);
            datePickerDialog.getWindow().setBackgroundDrawableResource(R.color.transparent);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_POSITIVE, "确定", datePickerDialog);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_NEGATIVE, "取消", (DialogInterface.OnClickListener)null);


            // datePickerDialog.setIcon(R.drawable.ic_001_busqueda);
            datePickerDialog.setTitle("月                      日                     年");

            // Popup the dialog.
            datePickerDialog.show();
        }
    });
}

private void showDatePickerDialog3()
{
    // Get open DatePickerDialog button.
    TextView datePickerDialogButton =(TextView) findViewById(R.id.tx2);
    datePickerDialogButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Create a new OnDateSetListener instance. This listener will be invoked when user click ok button in DatePickerDialog.
            DatePickerDialog.OnDateSetListener onDateSetListener = new DatePickerDialog.OnDateSetListener() {
                @Override
                public void onDateSet(DatePicker datePicker, int year, int month, int dayOfMonth) {
                    StringBuffer strBuf = new StringBuffer();
                    //   strBuf.append("");
                    strBuf.append(year);
                    strBuf.append(".");
                    strBuf.append(month+1);
                    strBuf.append(".");
                    strBuf.append(dayOfMonth);

                    TextView datePickerValueTextView = (TextView)findViewById(R.id.tx2);
                    datePickerValueTextView.setText(strBuf.toString());
                }
            };

            // Get current year, month and day.
            Calendar now = Calendar.getInstance();
            int year = now.get(java.util.Calendar.YEAR);
            int month = now.get(java.util.Calendar.MONTH);
            int day = now.get(java.util.Calendar.DAY_OF_MONTH);

            // Create the new DatePickerDialog instance.
            DatePickerDialog datePickerDialog = new DatePickerDialog(Principal.this, android.R.style.Theme_Holo_Light_Dialog, onDateSetListener, year, month, day);
            datePickerDialog.getWindow().setBackgroundDrawableResource(R.color.transparent);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_POSITIVE, "确定", datePickerDialog);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_NEGATIVE, "取消", (DialogInterface.OnClickListener)null);


            // datePickerDialog.setIcon(R.drawable.ic_001_busqueda);
            datePickerDialog.setTitle("月                      日                     年");

            // Popup the dialog.
            datePickerDialog.show();
        }
    });
}

private void showDatePickerDialog4()
{
    // Get open DatePickerDialog button.
    TextView datePickerDialogButton =(TextView) findViewById(R.id.tx3);
    datePickerDialogButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Create a new OnDateSetListener instance. This listener will be invoked when user click ok button in DatePickerDialog.
            DatePickerDialog.OnDateSetListener onDateSetListener = new DatePickerDialog.OnDateSetListener() {
                @Override
                public void onDateSet(DatePicker datePicker, int year, int month, int dayOfMonth) {
                    StringBuffer strBuf = new StringBuffer();
                    //   strBuf.append("");
                    strBuf.append(year);
                    strBuf.append(".");
                    strBuf.append(month+1);
                    strBuf.append(".");
                    strBuf.append(dayOfMonth);

                    TextView datePickerValueTextView = (TextView)findViewById(R.id.tx3);
                    datePickerValueTextView.setText(strBuf.toString());
                }
            };

            // Get current year, month and day.
            Calendar now = Calendar.getInstance();
            int year = now.get(java.util.Calendar.YEAR);
            int month = now.get(java.util.Calendar.MONTH);
            int day = now.get(java.util.Calendar.DAY_OF_MONTH);

            // Create the new DatePickerDialog instance.
            DatePickerDialog datePickerDialog = new DatePickerDialog(Principal.this, android.R.style.Theme_Holo_Light_Dialog, onDateSetListener, year, month, day);
            datePickerDialog.getWindow().setBackgroundDrawableResource(R.color.transparent);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_POSITIVE, "确定", datePickerDialog);
            datePickerDialog.setButton(DatePickerDialog.BUTTON_NEGATIVE, "取消", (DialogInterface.OnClickListener)null);


            // datePickerDialog.setIcon(R.drawable.ic_001_busqueda);
            datePickerDialog.setTitle("月                      日                     年");

            // Popup the dialog.
            datePickerDialog.show();
        }
    });
}
// Create and show a TimePickerDialog when click button.

public void lanzarProduct (View view){
    Intent i = new Intent(getApplicationContext(),Registrar_Producto.class);
    i.putExtra("UserEmailTAG", getIntent().getStringExtra("UserEmailTAG"));
    i.putExtra("seller_id", getIntent().getStringExtra("seller_id"));
    i.putExtra("shop_id", getIntent().getStringExtra("shop_id"));
    startActivity(i);
    finish();
}

public void lanzarLogout (View view){
    Toast.makeText(Principal.this, "Logged Out Successfully", Toast.LENGTH_LONG).show();
    finish();
    Intent intent = new Intent(Principal.this, Login.class);
    startActivity(intent);
}

@Override
public void onBackPressed(){
    AlertDialog.Builder mensaje=new AlertDialog.Builder(Principal.this);
    mensaje.setTitle("¿Are you sure you want to exit?");
    mensaje.setCancelable(false);
    mensaje.setPositiveButton("Accept", new DialogInterface.OnClickListener() {
@Override
        public void onClick(DialogInterface dialog, int which) {
            finish();
        }
    });
    mensaje.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
        public void onClick(DialogInterface dialog, int which) {
        }
    });
    mensaje.show();} }

Register_Product.java (here is the problem where the recycler view is located)

public class Registrar_Producto extends AppCompatActivity implements  DevelopersAdapter.ContactsAdapterListener {
private static final String TAG = Registrar_Producto.class.getSimpleName();
private static final String URL_DATA = "xxxxxxxxxxxx";
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private DevelopersAdapter mAdapter;
private List<DevelopersList> developersLists;
private SearchView searchView;
private String EMISOR = "";
private String EMISOR2 = "";
private String EMISOR3 = "";

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

    count=(TextView)findViewById(R.id.count) ;
    recyclerView =(RecyclerView) findViewById(R.id.recyclerView);
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));

    developersLists = new ArrayList<>();

    EMISOR = Preferences.obtenerPreferenceString(this,Preferences.PREFERENCE_USUARIO_LOGIN);
    EMISOR2 = Preferences.obtenerPreferenceString(this,Preferences.PREFERENCE_SELLER_ID);
    EMISOR3 = Preferences.obtenerPreferenceString(this,Preferences.PREFERENCE_SHOP_ID);

    Toast.makeText(this, EMISOR, Toast.LENGTH_SHORT).show();
    Toast.makeText(this, EMISOR2, Toast.LENGTH_SHORT).show();
    Toast.makeText(this, EMISOR3, Toast.LENGTH_SHORT).show();

    mAdapter = new DevelopersAdapter(this , developersLists , this );

    RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
    recyclerView.setLayoutManager(mLayoutManager);
    recyclerView.setItemAnimator(new DefaultItemAnimator());
    recyclerView.setAdapter(mAdapter);

    loadUrlData();
}

private void loadUrlData() {

    final ProgressDialog progressDialog = new ProgressDialog(this);
    progressDialog.setMessage("Loading...");
    progressDialog.show();

    StringRequest stringRequest = new StringRequest(Request.Method.POST,

            URL_DATA, new Response.Listener<String>() {
        @Override
        public void onResponse(String ServerResponse) {

            progressDialog.dismiss();

            try {
                String valor = getIntent().getStringExtra("UserEmailTAG");
                String valor2 = getIntent().getStringExtra("seller_id");
                String valor3 = getIntent().getStringExtra("shop_id");

                JSONObject jsonObject = new JSONObject(ServerResponse);
                String returnState= jsonObject.getString("returnState");
                String returnData= jsonObject.getString("returnData");

                JSONObject jsonObjectData= new JSONObject(returnData);
                String recordcount= jsonObjectData.getString("recordcount");
                count.setText(recordcount);
                JSONArray contacts = jsonObjectData.getJSONArray("data");
                for (int i = 0; i < contacts.length(); i++){

                    JSONObject jo = contacts.getJSONObject(i);
                    int position=i;
                    DevelopersList developers = new DevelopersList
                            (jo.getString("goods_name"),
                                    jo.getString("goods_no"),
                                    jo.getString("image_url"),
                                    jo.getString("min_price").substring(0,5),
                                    jo.getString("max_price").substring(0,5),
                                    jo.getString("sales_unit"));

                   developersLists.add(developers);
                    mAdapter.notifyDataSetChanged();
                }

            } catch (JSONException e) {

                e.printStackTrace();
            }
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

            Toast.makeText(Registrar_Producto.this, "Need internet access", Toast.LENGTH_SHORT).show();

        }
    }) {
        @Override
        protected Map<String, String> getParams() {

            // Creating Map String Params.
            Map<String, String> params = new HashMap<String, String>();

            // Adding All values to Params.
            // The firs argument should be same sa your MySQL database table columns.
            params.put("seller_id", getIntent().getStringExtra("seller_id"));

            return params;
        }
    };

    RequestQueue requestQueue = Volley.newRequestQueue(this);
    requestQueue.add(stringRequest);
}

@Override
public void onContactSelected(DevelopersList developersList) {
    Toast.makeText(getApplicationContext(), "Selected: " + developersList.getGoods_name() + ", " + developersList.getGoods_no(), Toast.LENGTH_LONG).show();
}

public void lanzarhome (View view) {
    Intent i = new Intent(this, Principal.class);
    i.putExtra("UserEmailTAG", getIntent().getStringExtra("UserEmailTAG"));
    i.putExtra("seller_id", getIntent().getStringExtra("seller_id"));
    i.putExtra("shop_id", getIntent().getStringExtra("shop_id"));
    startActivity(i);
}
public void lanzarRegistrarProducto(View view) {
    Intent i = new Intent(this, prueba.class);
    i.putExtra("UserEmailTAG", getIntent().getStringExtra("UserEmailTAG"));
    i.putExtra("seller_id", getIntent().getStringExtra("seller_id"));
    i.putExtra("shop_id", getIntent().getStringExtra("shop_id"));
    startActivity(i);
}

public void lanzarRegresar(View view) {
    Intent i = new Intent(this, Principal.class);
    i.putExtra("UserEmailTAG", getIntent().getStringExtra("UserEmailTAG"));
    i.putExtra("seller_id", getIntent().getStringExtra("seller_id"));
    i.putExtra("shop_id", getIntent().getStringExtra("shop_id"));
    startActivity(i);
}

public void lanzarSearchP(View view) {
    Intent i = new Intent(this, Search_products.class);
    i.putExtra("UserEmailTAG", getIntent().getStringExtra("UserEmailTAG"));
    i.putExtra("seller_id", getIntent().getStringExtra("seller_id"));
    i.putExtra("shop_id", getIntent().getStringExtra("shop_id"));
    startActivity(i);
} }

Preferences.java (class for sharedpreferences)

public class Preferences {


public static final String STRING_PREFERENCES = "datos.usuario.corpoasia_android";
public static final String PREFERENCE_ESTADO_BUTTON_SESION = "estado.button.sesion";
public static final String PREFERENCE_USUARIO_LOGIN = "usuario.login";
public static final String PREFERENCE_SHOP_ID = "shop.id";
public static final String PREFERENCE_SELLER_ID = "seller.id";


public static void savePreferenceBoolean(Context c, boolean b,String key){
    SharedPreferences preferences = c.getSharedPreferences(STRING_PREFERENCES,c.MODE_PRIVATE);
    preferences.edit().putBoolean(key,b).apply();
}

public static void savePreferendceString(Context c, String b,String key){
    SharedPreferences preferences = c.getSharedPreferences(STRING_PREFERENCES,c.MODE_PRIVATE);
    preferences.edit().putString(key,b).apply();
}

public static boolean obtenerPreferenceBoolean(Context c,String key){
    SharedPreferences preferences = c.getSharedPreferences(STRING_PREFERENCES,c.MODE_PRIVATE);
    return preferences.getBoolean(key,false);//Si es que nunca se ha guardado nada en esta key pues retornara false
}

public static String obtenerPreferenceString(Context c,String key){
    SharedPreferences preferences = c.getSharedPreferences(STRING_PREFERENCES,c.MODE_PRIVATE);
    return preferences.getString(key,"");//Si es que nunca se ha guardado nada en esta key pues retornara una cadena vacia
} }
    
asked by Johnny A. Rivas A. 20.08.2018 в 17:41
source

0 answers