Develop Reference

Android Volley Response

I am trying to create a simple login and if it is successful, I am trying to save the response userid (uid) into the shared preferences. Below is the part of my loginActivity.java and the error messages are:
Error 1
error: incompatible types: int cannot be converted to String
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.POST, Config.LOGIN_URL, null, new Response.Listener<JSONObject>() {
Error 2
error: cannot find symbol
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.POST,Config.LOGIN_URL, null, new Response.Listener<JSONObject>() {
^
symbol: constructor (int,String,,>)
LoginActivity.java
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.AppCompatButton;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import org.json.JSONObject;
import com.android.volley.Request.Method;
import com.android.volley.AuthFailureError;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import java.util.HashMap;
import java.util.Map;
public class LoginActivity extends AppCompatActivity implements View.OnClickListener {
//Defining views
private EditText editTextTCNO;
private EditText editTextMobile;
private AppCompatButton buttonLogin;
//boolean variable to check user is logged in or not
//initially it is false
private boolean loggedIn = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
ActionBar actionBar = getSupportActionBar();
actionBar.hide();
//Initializing views
editTextTCNO = (EditText) findViewById(R.id.editTextTCNO);
editTextMobile = (EditText) findViewById(R.id.editTextMobile);
buttonLogin = (AppCompatButton) findViewById(R.id.loginButton);
//Adding click listener
buttonLogin.setOnClickListener(this);
}
#Override
protected void onResume() {
super.onResume();
//In onresume fetching value from sharedpreference
SharedPreferences sharedPreferences = getSharedPreferences(Config.SHARED_PREF_NAME, Context.MODE_PRIVATE);
//Fetching the boolean value form sharedpreferences
loggedIn = sharedPreferences.getBoolean(Config.LOGGEDIN_SHARED_PREF, false);
//If we will get true
if(loggedIn){
//We will start the Profile Activity
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
}
}
private void login() {
//Getting values from edit texts
final String tcno = editTextTCNO.getText().toString().trim();
final String mobile = editTextMobile.getText().toString().trim();
final String operation = "login";
//Creating a string request
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.POST, Config.LOGIN_URL, null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
String smsg = response.getString("msg");
String pid = response.getString("uid");
//If we are getting success from server
if(smsg == Config.LOGIN_SUCCESS){
//Creating a shared preference
SharedPreferences sharedPreferences = LoginActivity.this.getSharedPreferences(Config.SHARED_PREF_NAME, Context.MODE_PRIVATE);
//Creating editor to store values to shared preferences
SharedPreferences.Editor editor = sharedPreferences.edit();
//Adding values to editor
editor.putBoolean(Config.LOGGEDIN_SHARED_PREF, true);
editor.putString(Config.UID_SHARED_PREF, pid);
//Saving values to editor
editor.commit();
//Starting profile activity
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
}else{
//If the server response is not success
//Displaying an error message on toast
Toast.makeText(LoginActivity.this, "Invalid username or password", Toast.LENGTH_LONG).show();
}
}
}){
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> params = new HashMap<>();
//Adding parameters to request
params.put(Config.KEY_TCNO, tcno);
params.put(Config.KEY_MOBILE, mobile);
params.put(Config.KEY_OPERATION, operation);
//returning parameter
return params;
}
};
//Adding the string request to the queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(jsonObjReq);
}
#Override
public void onClick(View v) {
//Calling the login function
login();
}
}

this is my fully functional way to make a volley request, hope it helps
private JSONObject LoginJson()
{
JSONObject jsonBody = new JSONObject();
try {
jsonBody.put("Username", "testUser");
jsonBody.put("Password", "123456");
} catch (JSONException e) {
e.printStackTrace();
}
return jsonBody;
}
public boolean identificarce ()
{
RequestFuture<JSONObject> future = RequestFuture.newFuture();
JsonObjectRequest request = new JsonObjectRequest(Request.Method.POST, URL.ServicioLogging, this.LoginJson(), future, future);
QueuHolder.getInstance(Login.contexto).getRequestQueue().add(request);
try {
JSONObject response = future.get();
try
{
String NombreCompleto = response.getString("NombreCompleto");
int id = response.getInt("id");
//save results in shared preferences
}
catch (JSONException e)
{
e.printStackTrace();
}
}
catch (Exception e)
{
e.printStackTrace();
return false;
}
return true;
}

Android User Login and Registration

I was following this tutorial (http://www.androidhive.info/2012/01/android-login-and-registration-with-php-mysql-and-sqlite/) to create a user login and registration for an application using volly. Everything works fine when I make it a stand alone app with no other features. The issue starts when I try integrate it with another application.
I am copying the classes produced from the tutorial straight into an existing project but I am getting a null pointer. Now before I go any further, I know what a null pointer is and I know how to solve them.
I am new-ish to Android and I am having trouble finding this one and would greatly appreciate some help with it rather then people just directing me to here -What is a NullPointerException, and how do I fix it? - as I have already looked at this but it still doesnt help me locate this error.
Login Activity
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.android.volley.Request.Method;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;
import com.example.rory.pocketchef.R;
import com.example.rory.pocketchef.app.AppConfig;
import com.example.rory.pocketchef.app.AppController;
import com.example.rory.pocketchef.helper.SQLiteHandler;
import com.example.rory.pocketchef.helper.SessionManager;
public class LoginActivity extends Activity {
private static final String TAG = RegisterActivity.class.getSimpleName();
private Button btnLogin;
private Button btnLinkToRegister;
private EditText inputEmail;
private EditText inputPassword;
private ProgressDialog pDialog;
private SessionManager session;
private SQLiteHandler db;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
inputEmail = (EditText) findViewById(R.id.email);
inputPassword = (EditText) findViewById(R.id.password);
btnLogin = (Button) findViewById(R.id.btnLogin);
btnLinkToRegister = (Button) findViewById(R.id.btnLinkToRegisterScreen);
// Progress dialog
pDialog = new ProgressDialog(this);
pDialog.setCancelable(false);
// SQLite database handler
db = new SQLiteHandler(getApplicationContext());
// Session manager
session = new SessionManager(getApplicationContext());
// Check if user is already logged in or not
if (session.isLoggedIn()) {
// User is already logged in. Take him to main activity
Intent intent = new Intent(LoginActivity.this, FirstActivity.class);
startActivity(intent);
finish();
}
// Login button Click Event
btnLogin.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
String email = inputEmail.getText().toString().trim();
String password = inputPassword.getText().toString().trim();
// Check for empty data in the form
if (!email.isEmpty() && !password.isEmpty()) {
// login user
checkLogin(email, password);
} else {
// Prompt user to enter credentials
Toast.makeText(getApplicationContext(),
"Please enter the credentials!", Toast.LENGTH_LONG)
.show();
}
}
});
// Link to Register Screen
btnLinkToRegister.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(),
RegisterActivity.class);
startActivity(i);
finish();
}
});
}
/**
* function to verify login details in mysql db
* */
private void checkLogin(final String email, final String password) {
// Tag used to cancel the request
String tag_string_req = "req_login";
pDialog.setMessage("Logging in ...");
showDialog();
StringRequest strReq = new StringRequest(Method.POST,
AppConfig.URL_LOGIN, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d(TAG, "Login Response: " + response.toString());
hideDialog();
try {
JSONObject jObj = new JSONObject(response);
boolean error = jObj.getBoolean("error");
// Check for error node in json
if (!error) {
// user successfully logged in
// Create login session
session.setLogin(true);
// Now store the user in SQLite
String uid = jObj.getString("uid");
JSONObject user = jObj.getJSONObject("user");
String name = user.getString("name");
String email = user.getString("email");
String created_at = user
.getString("created_at");
// Inserting row in users table
db.addUser(name, email, uid, created_at);
// Launch main activity
Intent intent = new Intent(LoginActivity.this, FirstActivity.class);
startActivity(intent);
finish();
} else {
// Error in login. Get the error message
String errorMsg = jObj.getString("error_msg");
Toast.makeText(getApplicationContext(),
errorMsg, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
// JSON error
e.printStackTrace();
Toast.makeText(getApplicationContext(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Login Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_LONG).show();
hideDialog();
}
}) {
#Override
protected Map<String, String> getParams() {
// Posting parameters to login url
Map<String, String> params = new HashMap<String, String>();
params.put("email", email);
params.put("password", password);
return params;
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}
private void showDialog() {
if (!pDialog.isShowing())
pDialog.show();
}
private void hideDialog() {
if (pDialog.isShowing())
pDialog.dismiss();
}
}
AppController
import android.app.Application;
import android.text.TextUtils;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.Volley;
public class AppController extends Application {
public static final String TAG = AppController.class.getSimpleName();
private RequestQueue mRequestQueue;
private static AppController mInstance;
#Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized AppController getInstance() {
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
public <T> void addToRequestQueue(Request<T> req, String tag) {
req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
getRequestQueue().add(req);
}
public <T> void addToRequestQueue(Request<T> req) {
req.setTag(TAG);
getRequestQueue().add(req);
}
public void cancelPendingRequests(Object tag) {
if (mRequestQueue != null) {
mRequestQueue.cancelAll(tag);
}
}
}
Android Manifest
<uses-permission android:name="android.permission.INTERNET" />
<android:uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<android:uses-permission android:name="android.permission.READ_PHONE_STATE" />
<android:uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_logo"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/MyMaterialTheme" >
<activity
android:name=".activity.LoginActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".SingleRecipeDisplay"
android:label="#string/title_activity_single_recipe_display"
android:theme="#style/MyMaterialTheme" >
</activity>
<activity android:name=".Favourites" >
</activity>
<activity android:name=".Help" >
</activity>
<activity android:name=".activity.RegisterActivity">
</activity>
</application>
Error
java.lang.NullPointerException: Attempt to invoke virtual method 'void
com.example.rory.pocketchef.app.AppController.addToRequestQueue(com.android.volley.Request,
java.lang.String)' on a null object reference 02-22 15:03:54.296
13823-13823/com.example.rory.pocketchef E/AndroidRuntime: at
com.example.rory.pocketchef.activity.LoginActivity.checkLogin(LoginActivity.java:183)
02-22 15:03:54.296 13823-13823/com.example.rory.pocketchef
E/AndroidRuntime: at
com.example.rory.pocketchef.activity.LoginActivity.access$200(LoginActivity.java:30)
02-22 15:03:54.296 13823-13823/com.example.rory.pocketchef
E/AndroidRuntime: at
com.example.rory.pocketchef.activity.LoginActivity$1.onClick(LoginActivity.java:78)

Your application instance is null. It's Singleton class but instance is never created.
Problem is that you missed to add name in <application> tag. Name should be AppController or even better full package path of AppController.
[EDIT]
And use this instead getApplicationContext() in AppController.

Null Pointer Exception in Android using List

I have following activities to load products from backend. Its a online food ordering with integration of paypal. I tried it in another app its working fine.
I am getting Error on onCreate Method.
There are three activities Item list , Product and product list adapter. I am getting error while loading view. When i commented the lines of adapter its not crashing but after adding the adapters its crashing . Its driving me crazy.
import com.flavorbaba.AppController;
import com.flavorbaba.Config;
import com.flavorbaba.Product;
import com.flavorbaba.ProductListAdapter;
import com.flavorbaba.ProductListAdapter.ProductListAdapterListener;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import com.android.volley.DefaultRetryPolicy;
import com.android.volley.Request.Method;
import com.android.volley.Response;
import com.android.volley.RetryPolicy;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.StringRequest;
import com.paypal.android.sdk.payments.PayPalConfiguration;
import com.paypal.android.sdk.payments.PayPalItem;
import com.paypal.android.sdk.payments.PayPalPayment;
import com.paypal.android.sdk.payments.PayPalPaymentDetails;
import com.paypal.android.sdk.payments.PayPalService;
import com.paypal.android.sdk.payments.PaymentActivity;
import com.paypal.android.sdk.payments.PaymentConfirmation;
public class ItemsList extends Activity implements ProductListAdapterListener {
private static final String TAG = ItemsList.class.getSimpleName();
private ListView listView;
private Button btnCheckout;
// To store all the products
private List<Product> productsList;
// To store the products those are added to cart
private List<PayPalItem> productsInCart = new ArrayList<PayPalItem>();
private ProductListAdapter adapter;
// Progress dialog
private ProgressDialog pDialog;
private static final int REQUEST_CODE_PAYMENT = 1;
// PayPal configuration
private static PayPalConfiguration paypalConfig = new PayPalConfiguration()
.environment(Config.PAYPAL_ENVIRONMENT).clientId(
Config.PAYPAL_CLIENT_ID);
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.food_menu);
listView = (ListView) findViewById(R.id.list);
btnCheckout = (Button) findViewById(R.id.checkout);
productsList = new ArrayList<Product>();
adapter = new ProductListAdapter(ItemsList.this, productsList, this);
pDialog = new ProgressDialog(this);
pDialog.setCancelable(false);
// Starting PayPal service
Intent intent = new Intent(this, PayPalService.class);
intent.putExtra(PayPalService.EXTRA_PAYPAL_CONFIGURATION, paypalConfig);
startService(intent);
// Checkout button click listener
btnCheckout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Check for empty cart
if (productsInCart.size() > 0) {
launchPayPalPayment();
} else {
Toast.makeText(getApplicationContext(),
"Cart is empty! Please add few products to cart.",
Toast.LENGTH_SHORT).show();
}
}
});
// Fetching products from server
fetchProducts();
}
/**
* Fetching the products from our server
* */
private void fetchProducts() {
// Showing progress dialog before making request
pDialog.setMessage("Fetching products...");
showpDialog();
// Making json object request
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.GET,
Config.URL_PRODUCTS, null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.d(TAG, response.toString());
try {
JSONArray products = response
.getJSONArray("products");
// looping through all product nodes and storing
// them in array list
for (int i = 0; i < products.length(); i++) {
JSONObject product = (JSONObject) products
.get(i);
String id = product.getString("p_id");
String name = product.getString("p_name");
String description = product
.getString("p_desc");
String image = product.getString("p_image");
BigDecimal price = new BigDecimal(product
.getString("p_price"));
String sku = product.getString("p_status");
Product p = new Product(id, name, description,
image, price, sku);
productsList.add(p);
}
listView.setAdapter(adapter);
// notifying adapter about data changes, so that the
// list renders with new data
adapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(),
"Error: " + e.getMessage(),
Toast.LENGTH_LONG).show();
}
// hiding the progress dialog
hidepDialog();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_SHORT).show();
// hide the progress dialog
hidepDialog();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(jsonObjReq);
}
/**
* Verifying the mobile payment on the server to avoid fraudulent payment
* */
private void verifyPaymentOnServer(final String paymentId,
final String payment_client) {
// Showing progress dialog before making request
pDialog.setMessage("Verifying payment...");
showpDialog();
StringRequest verifyReq = new StringRequest(Method.POST,
Config.URL_VERIFY_PAYMENT, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d(TAG, "verify payment: " + response.toString());
try {
JSONObject res = new JSONObject(response);
boolean error = res.getBoolean("error");
String message = res.getString("message");
// user error boolean flag to check for errors
Toast.makeText(getApplicationContext(), message,
Toast.LENGTH_SHORT).show();
if (!error) {
// empty the cart
productsInCart.clear();
}
} catch (JSONException e) {
e.printStackTrace();
}
// hiding the progress dialog
hidepDialog();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Verify Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_SHORT).show();
// hiding the progress dialog
hidepDialog();
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("paymentId", paymentId);
params.put("paymentClientJson", payment_client);
return params;
}
};
// Setting timeout to volley request as verification request takes
// sometime
int socketTimeout = 60000;
RetryPolicy policy = new DefaultRetryPolicy(socketTimeout,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
verifyReq.setRetryPolicy(policy);
// Adding request to request queue
AppController.getInstance().addToRequestQueue(verifyReq);
}
/**
* Preparing final cart amount that needs to be sent to PayPal for payment
* */
private PayPalPayment prepareFinalCart() {
PayPalItem[] items = new PayPalItem[productsInCart.size()];
items = productsInCart.toArray(items);
// Total amount
BigDecimal subtotal = PayPalItem.getItemTotal(items);
// If you have shipping cost, add it here
BigDecimal shipping = new BigDecimal("0.0");
// If you have tax, add it here
BigDecimal tax = new BigDecimal("0.0");
PayPalPaymentDetails paymentDetails = new PayPalPaymentDetails(
shipping, subtotal, tax);
BigDecimal amount = subtotal.add(shipping).add(tax);
PayPalPayment payment = new PayPalPayment(
amount,
Config.DEFAULT_CURRENCY,
"Description about transaction. This will be displayed to the user.",
Config.PAYMENT_INTENT);
payment.items(items).paymentDetails(paymentDetails);
// Custom field like invoice_number etc.,
payment.custom("This is text that will be associated with the payment that the app can use.");
return payment;
}
/**
* Launching PalPay payment activity to complete the payment
* */
private void launchPayPalPayment() {
PayPalPayment thingsToBuy = prepareFinalCart();
Intent intent = new Intent(ItemsList.this, PaymentActivity.class);
intent.putExtra(PayPalService.EXTRA_PAYPAL_CONFIGURATION, paypalConfig);
intent.putExtra(PaymentActivity.EXTRA_PAYMENT, thingsToBuy);
startActivityForResult(intent, REQUEST_CODE_PAYMENT);
}
/**
* Receiving the PalPay payment response
* */
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE_PAYMENT) {
if (resultCode == Activity.RESULT_OK) {
PaymentConfirmation confirm = data
.getParcelableExtra(PaymentActivity.EXTRA_RESULT_CONFIRMATION);
if (confirm != null) {
try {
Log.e(TAG, confirm.toJSONObject().toString(4));
Log.e(TAG, confirm.getPayment().toJSONObject()
.toString(4));
String paymentId = confirm.toJSONObject()
.getJSONObject("response").getString("id");
String payment_client = confirm.getPayment()
.toJSONObject().toString();
Log.e(TAG, "paymentId: " + paymentId
+ ", payment_json: " + payment_client);
// Now verify the payment on the server side
verifyPaymentOnServer(paymentId, payment_client);
} catch (JSONException e) {
Log.e(TAG, "an extremely unlikely failure occurred: ",
e);
}
}
} else if (resultCode == Activity.RESULT_CANCELED) {
Log.e(TAG, "The user canceled.");
} else if (resultCode == PaymentActivity.RESULT_EXTRAS_INVALID) {
Log.e(TAG,
"An invalid Payment or PayPalConfiguration was submitted.");
}
}
}
private void showpDialog() {
if (!pDialog.isShowing())
pDialog.show();
}
private void hidepDialog() {
if (pDialog.isShowing())
pDialog.dismiss();
}
#Override
public void onAddToCartPressed(Product product) {
PayPalItem item = new PayPalItem(product.getname(), 1,
product.getprice(), Config.DEFAULT_CURRENCY, product.getsku());
productsInCart.add(item);
Toast.makeText(getApplicationContext(),
item.getName() + " added to cart!", Toast.LENGTH_SHORT).show();
}
}
--------------------------------------------------------------------------
import java.math.BigDecimal;
public class Product {
private String id, name, description, image, sku;
private BigDecimal price;
public Product() {
}
public Product(String id, String name, String description, String image,
BigDecimal price, String sku) {
this.id = id;
this.name = name;
this.description = description;
this.image = image;
this.price = price;
this.sku = sku;
}
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;
}
public String getdescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getimage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
public BigDecimal getprice() {
return price;
}
public String getsku() {
return sku;
}
}
---------------------------------------------------------------
package com.flavorbaba;
import com.flavorbaba.R;
import com.flavorbaba.AppController;
import java.util.List;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.TextView;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.NetworkImageView;
public class ProductListAdapter extends BaseAdapter {
private Activity activity;
private LayoutInflater inflater;
private List<Product> products;
private ProductListAdapterListener listener;
ImageLoader imageLoader = AppController.getInstance().getImageLoader();
public ProductListAdapter(Activity activity, List<Product> feedItems,
ProductListAdapterListener listener) {
this.activity = activity;
this.products = feedItems;
this.listener = listener;
}
#Override
public int getCount() {
return products.size();
}
#Override
public Object getItem(int location) {
return products.get(location);
}
#Override
public long getItemId(int position) {
return position;
}
#SuppressLint("InflateParams")
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null)
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
convertView = inflater.inflate(R.layout.list_item_product, null);
if (imageLoader == null)
imageLoader = AppController.getInstance().getImageLoader();
TextView name = (TextView) convertView.findViewById(R.id.productName);
TextView description = (TextView) convertView
.findViewById(R.id.productDescription);
TextView price = (TextView) convertView.findViewById(R.id.productPrice);
NetworkImageView image = (NetworkImageView) convertView
.findViewById(R.id.productImage);
Button btnAddToCart = (Button) convertView
.findViewById(R.id.btnAddToCart);
final Product product = products.get(position);
name.setText(product.getname());
description.setText(product.getdescription());
price.setText("Price: $" + product.getprice());
// user profile pic
image.setImageUrl(product.getimage(), imageLoader);
btnAddToCart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
listener.onAddToCartPressed(product);
}
});
return convertView;
}
public interface ProductListAdapterListener {
public void onAddToCartPressed(Product product);
}
}

This is a lot ta code dude...
I Wonder why your Productlistadapter object needs two contexts and why you give the first context as Item activity.this but nevertheless
One big Problem here is that you are trying to make a network connection on the main thread...that's an error when you are in strict mode while debugging...

app crashes when try to create new record on remote database mysql using volley

I have created a simple android app which connect to Remote sql database.. the problem is when I click on register the application crash. please help me guys
package com.example.akshay.webservices;
/**
* Created by Akshay on 7/20/2015.
*/
import com.example.akshay.webservices.AppConfig;
import com.example.akshay.webservices.AppController;
import com.example.akshay.webservices.SQLiteHandler;
import com.example.akshay.webservices.SessionManager;
import java.util.HashMap;
import java.util.Map;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.android.volley.Request.Method;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
public class RegisterActivity extends Activity {
private static final String TAG = RegisterActivity.class.getSimpleName();
private Button btnRegister;
private Button btnLinkToLogin;
private EditText inputFullName;
private EditText inputEmail;
private EditText inputPassword;
private ProgressDialog pDialog;
private SessionManager session;
private SQLiteHandler db;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
inputFullName = (EditText) findViewById(R.id.name);
inputEmail = (EditText) findViewById(R.id.email);
inputPassword = (EditText) findViewById(R.id.password);
btnRegister = (Button) findViewById(R.id.btnRegister);
btnLinkToLogin = (Button) findViewById(R.id.btnLinkToLoginScreen);
// Progress dialog
pDialog = new ProgressDialog(this);
pDialog.setCancelable(false);
// Session manager
session = new SessionManager(getApplicationContext());
// SQLite database handler
db = new SQLiteHandler(getApplicationContext());
// Check if user is already logged in or not
if (session.isLoggedIn()) {
// User is already logged in. Take him to main activity
Intent intent = new Intent(RegisterActivity.this,
MainActivity.class);
startActivity(intent);
finish();
}
// Register Button Click event
btnRegister.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
String name = inputFullName.getText().toString();
String email = inputEmail.getText().toString();
String password = inputPassword.getText().toString();
if (!name.isEmpty() && !email.isEmpty() && !password.isEmpty()) {
registerUser(name, email, password);
} else {
Toast.makeText(getApplicationContext(),
"Please enter your details!", Toast.LENGTH_LONG)
.show();
}
}
});
// Link to Login Screen
btnLinkToLogin.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(),
LoginActivity.class);
startActivity(i);
finish();
}
});
}
/**
* Function to store user in MySQL database will post params(tag, name,
* email, password) to register url
* */
private void registerUser(final String name, final String email,
final String password) {
// Tag used to cancel the request
String tag_string_req = "req_register";
pDialog.setMessage("Registering ...");
showDialog();
StringRequest strReq = new StringRequest(Method.POST,
AppConfig.URL_REGISTER, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d(TAG, "Register Response: " + response.toString());
hideDialog();
try {
JSONObject jObj = new JSONObject(response);
boolean error = jObj.getBoolean("error");
if (!error) {
// User successfully stored in MySQL
// Now store the user in sqlite
String uid = jObj.getString("uid");
JSONObject user = jObj.getJSONObject("user");
String name = user.getString("name");
String email = user.getString("email");
String created_at = user
.getString("created_at");
// Inserting row in users table
db.addUser(name, email, uid, created_at);
// Launch login activity
Intent intent = new Intent(
RegisterActivity.this,
LoginActivity.class);
startActivity(intent);
finish();
} else {
// Error occurred in registration. Get the error
// message
String errorMsg = jObj.getString("error_msg");
Toast.makeText(getApplicationContext(),
errorMsg, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Registration Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_LONG).show();
hideDialog();
}
}) {
#Override
protected Map<String, String> getParams() {
// Posting params to register url
Map<String, String> params = new HashMap<String, String>();
params.put("tag", "register");
params.put("name", name);
params.put("email", email);
params.put("password", password);
return params;
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}
private void showDialog() {
if (!pDialog.isShowing())
pDialog.show();
}
private void hideDialog() {
if (pDialog.isShowing())
pDialog.dismiss();
}
}
AppController.java
package com.example.akshay.webservices;
import android.app.Application;
/**
* Created by Akshay on 7/19/2015.
*/
import android.app.Application;
import android.text.TextUtils;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.Volley;
public class AppController extends Application {
public static final String TAG = AppController.class.getSimpleName();
private RequestQueue mRequestQueue;
private static AppController mInstance;
#Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized AppController getInstance() {
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
public <T> void addToRequestQueue(Request<T> req, String tag) {
req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
getRequestQueue().add(req);
}
public <T> void addToRequestQueue(Request<T> req) {
req.setTag(TAG);
getRequestQueue().add(req);
}
public void cancelPendingRequests(Object tag) {
if (mRequestQueue != null) {
mRequestQueue.cancelAll(tag);
}
}
}
LogCat:
07-20 20:27:07.195 8233-8233/? E/Zygote﹕ MountEmulatedStorage()
07-20 20:27:07.195 8233-8233/? E/Zygote﹕ v2
07-20 20:27:07.195 8233-8233/? E/SELinux﹕ [DEBUG] get_category: variable seinfo: default sensitivity: NULL, cateogry: NULL
07-20 20:27:18.355 8233-8233/com.example.akshay.webservices E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.akshay.webservices, PID: 8233
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.akshay.webservices.AppController.addToRequestQueue(com.android.volley.Request, java.lang.String)' on a null object reference
at com.example.akshay.webservices.RegisterActivity.registerUser(RegisterActivity.java:185)
at com.example.akshay.webservices.RegisterActivity.access$300(RegisterActivity.java:32)
at com.example.akshay.webservices.RegisterActivity$1.onClick(RegisterActivity.java:81)
at android.view.View.performClick(View.java:5191)
at android.view.View$PerformClick.run(View.java:20916)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5972)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
This is the logcat I am unable to understand what is happening. Please help..

Problem is happening cause AppController.getInstance() it's returning null,
you have to change your AppController.getInstance() method to be this way:
public static AppController getInstance() {
if (mInstance == null) {
mInstance = new AppController;
}
return mInstance;
}
also make sure that you are registering your app class in your manifest
you should have an attribute in your manifest app like this:
<application
android:name="package.AppController" <--------
android:allowBackup="true"
android:debuggable="true"
android:icon="#drawable/ic_launcher"
android:label="xyz"
android:screenOrientation="landscape"
android:theme="#style/AppTheme">
More info here: http://developer.android.com/reference/android/app/Application.html
"Base class for those who need to maintain global application state. You can provide your own implementation by specifying its name in your AndroidManifest.xml's tag, which will cause that class to be instantiated for you when the process for your application/package is created. "

Hey i had the same issue and when i tried this solution it did not work finally i got a way out.
The problem why it is returning a null pointer is because the methods getInstance() and getRequestQueue() are returning nothing with respect to the context. To solve that follow this steps. As prerequisite ad the following global variable in under public class AppController extends Application private Context myContext.
STEP 1.
Create a constructor that defines the context
public AppController(Context context){
myContext = context;
mRequestQueue = getRequestQueue();
}
STEP 2. Modify hyou getInstance() method to work within the context as follow:
public static synchronized AppController getInstance(Context context) {
if(mInstance==null){
mInstance = new AppController(context);
}
return mInstance;
}
Step 3.
Finally modify the getRequestQueue() method to work within the context as follows
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(myContext.getApplicationContext());
}
return mRequestQueue;
}
Finally got the calling class and call the methods from AppController.java with respect to the context of the activity or broadcaster.
AppController.getInstance(this).addToRequestQueue(strReq, tag_string_req);

android java : persisitent login application

I am trying to make an persistent login application which then read sms from my phone and sends them to the an api with meaage body as well as the date and sender information. How can I proceed for the same.
I have made the login app but persistent login like facebook and other applications is not working.
Here is my code for the login application:
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import java.util.ArrayList;
public class LoginActivity extends ActionBarActivity {
private EditText un,pw;
private Button sign;
private TextView msg;
private String resp, errorMsg;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
un = (EditText) findViewById(R.id.et_Username);
pw = (EditText) findViewById(R.id.et_Password);
sign = (Button) findViewById(R.id.bt_SignIn);
msg = (TextView) findViewById(R.id.tv_error);
sign.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
/**
* According with the new StrictGuard policy, running long tasks
* on the Main UI thread is not possible So creating new thread
* to create and execute http operations
*/
new Thread(new Runnable() {
#Override
public void run() {
ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("username",
un.getText().toString()));
postParameters.add(new BasicNameValuePair("password",
pw.getText().toString()));
String response = null;
try {
response = SimpleHttpClient
.executeHttpPost(
url,
postParameters);
String res = response.toString();
System.out.println(res);
resp = res.replaceAll("\\s+", "");
} catch (Exception e) {
e.printStackTrace();
errorMsg = e.getMessage();
}
}
}).start();
try {
Thread.sleep(1000);
/**
* Inside the new thread we cannot update the main thread So
* updating the main thread outside the new thread
*/
msg.setText(resp);
if (null != errorMsg && !errorMsg.isEmpty()) {
msg.setText(errorMsg);
}
} catch (Exception e) {
msg.setText(e.getMessage());
}
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
I tried this now,got the idea for shred prefernece but somewhow its not working for me
I tried this it doesn't show my main activity:
Can you find the problem:
MainActivity:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import java.util.ArrayList;
public class MainActivity extends Activity {
private String resp, errorMsg;
private EditText username,password;
/*public static final String MyPREFERENCES = "MyPrefs" ;
public static final String name = "nameKey";
public static final String pass = "passwordKey";
SharedPreferences sharedpreferences;*/
SessionManager session;
private TextView msg;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
username = (EditText)findViewById(R.id.editText1);
password = (EditText)findViewById(R.id.editText2);
msg = (TextView) findViewById(R.id.tv_error);
session = new SessionManager(this);
}
#Override
protected void onResume() {
//sharedpreferences=getSharedPreferences(MyPREFERENCES,
// Context.MODE_PRIVATE);
if (session.getuser()!=null)
{
if(session.getpassword()!=null){
Intent i = new Intent(this,
Welcome.class);
startActivity(i);
}
}
super.onResume();
}
public void login(View view){
String u = username.getText().toString();
String p = password.getText().toString();
{
/**
* According with the new StrictGuard policy, running long tasks
* on the Main UI thread is not possible So creating new thread
* to create and execute http operations
*/
new Thread(new Runnable() {
#Override
public void run() {
ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("username",
username.getText().toString()));
postParameters.add(new BasicNameValuePair("password",
password.getText().toString()));
String response = null;
try {
response = SimpleHttpClient
.executeHttpPost(
"<url>",
postParameters);
String res = response.toString();
//System.out.println(res);
resp = res.replaceAll("\\s+", "");
} catch (Exception e) {
e.printStackTrace();
errorMsg = e.getMessage();
}
}
}).start();
try {
Thread.sleep(1000);
/**
* Inside the new thread we cannot update the main thread So
* updating the main thread outside the new thread
*/
msg.setText(resp);
if (null != errorMsg && !errorMsg.isEmpty()) {
msg.setText(errorMsg);
}
} catch (Exception e) {
msg.setText(e.getMessage());
}
}
if (resp.contains("false")) {
session.saveSession(u, p);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
}
Welcome:
import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
public class Welcome extends Activity {
SessionManager session;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_welcome);
session = new SessionManager(this);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
//. getMenuInflater().inflate(R.menu, menu);
return true;
}
public void logout(View view){
session.logoutUser();
moveTaskToBack(true);
Welcome.this.finish();
}
public void exit(View view){
moveTaskToBack(true);
Welcome.this.finish();
}
public List<Sms> getAllSms() {
List<Sms> lstSms = new ArrayList<Sms>();
Sms objSms = new Sms();
Uri message = Uri.parse("content://sms/inbox");
ContentResolver cr = this.getContentResolver();
Cursor c = cr.query(message, null, null, null, null);
this.startManagingCursor(c);
int totalSMS = c.getCount();
if (c.moveToFirst()) {
for (int i = 0; i < totalSMS; i++) {
if(c.getString(c.getColumnIndexOrThrow("address")).contains("icicib")|| c.getString(c.getColumnIndexOrThrow("address")).contains("hdfcbk") || c.getString(c.getColumnIndexOrThrow("address")).contains("dbalrt")
||c.getString(c.getColumnIndexOrThrow("address")).contains("citibk")||c.getString(c.getColumnIndexOrThrow("address")).contains("unionb")||c.getString(c.getColumnIndexOrThrow("address")).contains("atmsbi")
|| c.getString(c.getColumnIndexOrThrow("address")).contains("sbiinb") || c.getString(c.getColumnIndexOrThrow("address")).contains("indusb") ||c.getString(c.getColumnIndexOrThrow("address")).contains("fedbnk")
|| c.getString(c.getColumnIndexOrThrow("address")).contains("kotakb")||c.getString(c.getColumnIndexOrThrow("address")).contains("axisbk")||c.getString(c.getColumnIndexOrThrow("address")).contains("pnbsms")
|| c.getString(c.getColumnIndexOrThrow("address")).contains("hsbcin") || c.getString(c.getColumnIndexOrThrow("address")).contains("canbnk") || c.getString(c.getColumnIndexOrThrow("address")).contains("idbi")
||c.getString(c.getColumnIndexOrThrow("address")).contains("iob") || c.getString(c.getColumnIndexOrThrow("address")).contains("citibk") || c.getString(c.getColumnIndexOrThrow("address")).contains("hdfcbk")
||c.getString(c.getColumnIndexOrThrow("address")).contains("fromsc") ||c.getString(c.getColumnIndexOrThrow("address")).contains("myamex") || c.getString(c.getColumnIndexOrThrow("address")).contains("26463872")
|| c.getString(c.getColumnIndexOrThrow("address")).contains("sbicrd") || c.getString(c.getColumnIndexOrThrow("address")).contains("icici?") || c.getString(c.getColumnIndexOrThrow("address")).contains("syndbk")
|| c.getString(c.getColumnIndexOrThrow("address")).contains("121") || c.getString(c.getColumnIndexOrThrow("address")).contains("best deal(121)") || c.getString(c.getColumnIndexOrThrow("address")).contains("airtel")
|| c.getString(c.getColumnIndexOrThrow("address")).contains("vfcare") || c.getString(c.getColumnIndexOrThrow("address")).contains("vodafone") || c.getString(c.getColumnIndexOrThrow("address")).contains("mytsky")||c.getString(c.getColumnIndexOrThrow("address")).contains("dishpy") ) {
objSms = new Sms();
objSms.setAddress(c.getString(c .getColumnIndexOrThrow("address")));
objSms.setMsg(c.getString(c.getColumnIndexOrThrow("body")));
objSms.setTime(c.getString(c.getColumnIndexOrThrow("date")));
lstSms.add(objSms);
}
c.moveToNext();
}
}
// else {
// throw new RuntimeException("You have no SMS");
// }
c.close();
return lstSms;
}
}
SessionManager:
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
public class SessionManager {
SharedPreferences pref;
SharedPreferences.Editor editor;
Context _context;
int PRIVATE_MODE = 0;
private static final String PREFER_NAME = "AndroidExamplePref";
public static final String KEY_USER = "username";
public static final String KEY_PWD = "password";
public SessionManager(Context context){
this._context = context;
pref = _context.getSharedPreferences(PREFER_NAME, PRIVATE_MODE);
editor = pref.edit();
}
public void saveSession(String user, String pwd){
editor.putString(KEY_USER, user);
editor.putString(KEY_PWD, pwd);
editor.commit();
}
public String getuser()
{
String s = pref.getString(KEY_USER,"");
return s;
}
public String getpassword()
{
String p = pref.getString(KEY_PWD,"");
return p;
}
public void logoutUser(){
editor.clear();
editor.commit();
Intent i = new Intent(_context,.MainActivity.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
_context.startActivity(i);
}
}
AndroidManifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package=".sample" >
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.RECEIVE_SMS" />
<uses-permission android:name="android.permission.read_sms" />
<uses-permission android:name="android.permission.SEND_SMS" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Welcome"
android:label="#string/title_activity_welcome" >
</activity>
</application>
</manifest>
UPDATED ANSWER:
IT works now
i made session as static and before logging I am checking the shared preference value and accordingly going ahead. Everything is working now.

I guess you are meaning "persistent login application" -> User will log in once & for the next time they will not need to log in again with user name & password, right?
For this the naive approach would be storing the username & password in shared preference / db. But its not a good approach as it stores the password.
Instead of doing this, you can store, the userId/access token (obtained from the response). You should also have an expiration time so that you can prompt for log in validating the userId/access token after certain time.
Facebook seems to do the same thing I guess. E.g. if you clear data from on facebook app, then you does need to log in again.
I hope this gives you a direction.
Updated Answer
I guess you are not clear about pref.getString() method. The overloaded method (with 2 param) will return the 2nd param you sent, if any value with the query KEY (the 1st param)is not found.
In your case, in
public String getuser()
{
String s = pref.getString(KEY_USER,""); // here is the error, "" is not null, its an empty String.
return s;
}
So you can change this trouble causing line into either of the following line-
String s = pref.getString(KEY_USER,null);
or
String s = pref.getString(KEY_USER);
Same problem in the getuser(). Hopefully this will solve your problem :)