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sqllite db android not adding user properly

I am getting a "Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference"
public class userDB extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "UserInfo";
// Assignment table name
private static final String TABLE_USERINFO = "user";
// Assignment Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_TOKEN = "token";
Context context;
public userDB (Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_USERINFO + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_TOKEN + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
// Upgrading database
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_USERINFO);
// Create tables again
onCreate(db);
}
/**
* All CRUD(Create, Read, Update, Delete) Operations
*/
// Adding user
public void addUser(authToken user) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_TOKEN, user.getToken());
// Inserting Row
db.insert(TABLE_USERINFO, null, values);
Toast.makeText(context, "Inserted" + values.toString() , Toast.LENGTH_LONG).show();
db.close(); // Closing database connection
}
// Getting All Users
public List<authToken> getAllUsers() {
List<authToken> userList = new ArrayList<>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_USERINFO;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
authToken user = new authToken();
user.setToken(cursor.getString(1));
// Adding user to list
userList.add(user);
} while (cursor.moveToNext());
}
// return user list
return userList;
}
// Update User
public int updateUser(authToken user) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_TOKEN, user.getToken());
// updating row
return db.update(TABLE_USERINFO, values, KEY_ID + " = ?",
new String[] { String.valueOf(user.getUser().getId())});
}
// Delete user
public void deleteUser(authToken user) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_USERINFO, KEY_ID + " = ?",
new String[] { String.valueOf(user.getToken()) });
db.close();
}
// Getting User Count
public int getUserCount() {
String countQuery = "SELECT * FROM " + TABLE_USERINFO;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
}
I am reading the info in like this: (and userinfo.getToken) is spitting out the token, its something with the sql not adding in db properly.
userDB db = new userDB(getApplicationContext());
dbs = db.getWritableDatabase();
//db.onUpgrade(dbs, 1, 1);
// Inserting Contacts
Log.d("Insert: ", "Inserting .." +
userInfo.getToken());
db.addUser(new authToken(userInfo.getToken()));
// Reading all
Log.d("Reading: ", "Reading all contacts..");
List<authToken> contacts = db.getAllUsers();
for (authToken cn : contacts) {
String log = "Token: " + cn.getToken();
// Writing Contacts to log
Log.d("Name: ", log);
}

Where are you setting context? I think the problem is with the toast message.
You should set context in your constructor method:
Context context;
public userDB (Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.context = context;
}

This may not be related but in the method getUserCount(), cursor.getCount() should be called before cursor.close().

SQLiteDatabase add only if not already there

I'm implementing a "add to favorite" function. Where the user should be able to add data to a database.
The DatabaseHandler is working and I've created a class to handle get/set methods.
I can easily add data to the database, but I can't quite figure out how to check if a specific id is already present and thereby not adding a duplicate to the database.
Here's my DatabaseHandler:
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "favoriteMovies";
// DataFavorites table name
private static final String TABLE_NAME = "movies";
// DataFavorites Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_TITLE = "title";
private static final String KEY_URL = "url";
private static final String KEY_RELEASEDATE = "releaseDate";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_DATAFAVORITES_TABLE = "CREATE TABLE " + TABLE_NAME + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_TITLE + " TEXT,"
+ KEY_URL + " TEXT,"+ KEY_RELEASEDATE + " TEXT" + ")";
db.execSQL(CREATE_DATAFAVORITES_TABLE);
}
// Upgrading database
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
// Create tables again
onCreate(db);
}
// Adding new movie
public void addMovie(DataFavorites movie) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ID, movie.getId()); // movie id
values.put(KEY_TITLE, movie.getTitle()); // movie title
values.put(KEY_URL, movie.getUrl()); // movie url (poster)
values.put(KEY_RELEASEDATE, movie.getReleaseDate()); // movie url (poster)
// Inserting Row
db.insert(TABLE_NAME, null, values);
db.close(); // Closing database connection
}
// Getting single movie
public DataFavorites getMovie(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_NAME, new String[] { KEY_ID,
KEY_TITLE, KEY_URL, KEY_RELEASEDATE }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
DataFavorites movie = new DataFavorites(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2), cursor.getString(3));
// return movie
return movie;
}
// Getting All movie
public List<DataFavorites> getAllMovie() {
List<DataFavorites> movieList = new ArrayList<DataFavorites>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
DataFavorites dataFavorites = new DataFavorites();
dataFavorites.setId(Integer.parseInt(cursor.getString(0)));
dataFavorites.setTitle(cursor.getString(1));
dataFavorites.setUrl(cursor.getString(2));
dataFavorites.setReleaseDate(cursor.getString(3));
// Adding movie to list
movieList.add(dataFavorites);
} while (cursor.moveToNext());
}
// return movie list
return movieList;
}
// Getting movie Count
public int getMoviesCount(){
String countQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
// Updating single movie
public int updateMovie(DataFavorites movie) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ID, movie.getId());
values.put(KEY_TITLE, movie.getTitle());
values.put(KEY_URL, movie.getUrl());
values.put(KEY_RELEASEDATE, movie.getReleaseDate());
// updating row
return db.update(TABLE_NAME, values, KEY_ID + " = ?",
new String[] { String.valueOf(movie.getId()) });
}
// Deleting single movie
public void deleteMovie(DataFavorites movie) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_NAME, KEY_ID + " = ?",
new String[] { String.valueOf(movie.getId()) });
db.close();
}
And here I want to add data if id doesn't already exist:
public void AddToFavorites(MenuItem item) {
DatabaseHandler db = new DatabaseHandler(this);
/* if ( id is not there ){
// Inserting movie
Log.d("Insert: ", "Inserting movie..");
db.addMovie(new DataFavorites(Integer.parseInt(Id), Title, Poster, Release));
} */
}

Add a UNIQUE index to the Table column to prevent duplicate entries. Also note that it will throw an Exception if duplicate is inserted, so don't forget to handle that

you should use :
db.execSql("INSERT OR IGNORE INTO movies (columns names) VALUES (your values)");
or
db.execSql("INSERT OR REPLACE INTO movies (columns names) VALUES (your values)");
to insert the values, if they are already in the table they will not be added(first method) or they will be replaced(second method).

How to read SQLite by cursor and display in textview

How to read and display "email" and "address" in HomeAcitivity TextView.
The database designed to be store only 1 row of data.
DatabaseHandler.java
package com.example.androidjhfong.library;
import java.util.HashMap;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "android_database";
// Table name
private static final String TABLE_LOGIN = "login";
// Login Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_EMAIL = "email";
private static final String KEY_UID = "uid";
private static final String KEY_ADDRESS = "address";
private static final String KEY_PHONE = "phone";
private static final String KEY_CREATED_AT = "created_at";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_LOGIN_TABLE = "CREATE TABLE " + TABLE_LOGIN + "("
+ KEY_ID + " INTEGER PRIMARY KEY,"
+ KEY_NAME + " TEXT,"
+ KEY_EMAIL + " TEXT UNIQUE,"
+ KEY_UID + " TEXT,"
+ KEY_ADDRESS + " TEXT,"
+ KEY_PHONE + " TEXT,"
+ KEY_CREATED_AT + " TEXT" + ")";
db.execSQL(CREATE_LOGIN_TABLE);
}
// Upgrading database
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_LOGIN);
// Create tables again
onCreate(db);
}
/**
* Storing user details in database
* */
public void addUser(String name, String email, String uid, String address, String phone, String created_at) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, name); // Name
values.put(KEY_EMAIL, email); // Email
values.put(KEY_UID, uid); // Email
values.put(KEY_ADDRESS, address); // Address
values.put(KEY_PHONE, phone); // phone
values.put(KEY_CREATED_AT, created_at); // Created At
// Inserting Row
db.insert(TABLE_LOGIN, null, values);
db.close(); // Closing database connection
}
/**
* Getting user data from database
* */
public HashMap<String, String> getUserDetails(){
HashMap<String,String> user = new HashMap<String,String>();
String selectQuery = "SELECT * FROM " + TABLE_LOGIN;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// Move to first row
cursor.moveToFirst();
if(cursor.getCount() > 0){
user.put("name", cursor.getString(1));
user.put("email", cursor.getString(2));
user.put("uid", cursor.getString(3));
user.put("address", cursor.getString(4));
user.put("phone", cursor.getString(5));
user.put("created_at", cursor.getString(6));
}
cursor.close();
db.close();
// return user
return user;
}
/**
* Getting user login status
* return true if rows are there in table
* */
public int getRowCount() {
String countQuery = "SELECT * FROM " + TABLE_LOGIN;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int rowCount = cursor.getCount();
db.close();
cursor.close();
// return row count
return rowCount;
}
/**
* Re crate database
* Delete all tables and create them again
* */
public void resetTables(){
SQLiteDatabase db = this.getWritableDatabase();
// Delete All Rows
db.delete(TABLE_LOGIN, null, null);
db.close();
}
/**
* Getting product status
**/
public String getData() {
String username;
String getdata = "SELECT name FROM " + TABLE_LOGIN;
//String[] columns = new String[]{ KEY_ID, KEY_NAME, KEY_ADDRESS, KEY_PHONE};
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(getdata, null);
cursor.moveToFirst();
username=cursor.getString(cursor.getColumnIndex("name"));
cursor.close();
db.close();
return username;
}
}
how to display the retrieve the data and display in HomeActivity correctly?
HomeActivity
public class HomeActivity extends Activity implements OnItemSelectedListener{
TextView inputname
TextView inputemail;
TextView inputaddress;
Button btnPurchase;
// JSON Response node names
private static String KEY_SUCCESS = "success";
private static String KEY_ADDRESS = "address";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.Home);
inputname= (TextView) findViewById(R.id.qrpurchaseitem);
inputaddress = (TextView) findViewById(R.id.qrtextpurchaseaddress);
inputemail = (TextView) findViewById(R.id.qrtextpurchasecomment);
DatabaseHandler db = new DatabaseHandler(getApplicationContext());
HashMap<String, String> key = db.getUserDetails();
String text= DatabaseHandler.getUserDetails();
}

in your HomeActivty add this both line
String email=db.getEmail()
String address=db.getAddress();
Now then you can use below method in you Database Handler class, just change variable name from below methods
public String getStartBal() {
Cursor cr=ourDatabase.rawQuery("SELECT "+KEY_START_BAL+" FROM "+DB_TABLE,null);
String sum="";
for(cr.moveToFirst();!cr.isAfterLast();cr.moveToNext()){
sum=cr.getString(cr.getColumnIndex(KEY_START_BAL));
}
cr.close();
return sum;
}

No data retrieved if open sqlite more than once

When I add data into sqlite and open it for the first time, the data inside will be displayed. However, if I try opening it again nothing will show up even though there is data inside. May I know what is the problem?
Class that performs the activity:
public class Watchlist extends ListActivity {
private ArrayList<String> results = new ArrayList<String>();
private String tableName = DatabaseHandler.TABLE_ITEM;
private SQLiteDatabase newDB;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
openAndQueryDatabase();
displayResultList();
}
private void displayResultList() {
TextView tView = new TextView(this);
tView.setText("This data is retrieved from sqlite");
getListView().addHeaderView(tView);
setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, results));
getListView().setTextFilterEnabled(true);
}
private void openAndQueryDatabase() {
try {
DatabaseHandler db = new DatabaseHandler(this.getApplicationContext());
newDB = db.getWritableDatabase();
Cursor c = newDB.rawQuery("SELECT * FROM " + tableName, null);
if (c != null ) {
if (c.moveToFirst()) {
do {
String pid = c.getString(c.getColumnIndex("id"));
String name = c.getString(c.getColumnIndex("name"));
String price = c.getString(c.getColumnIndex("price"));
String date = c.getString(c.getColumnIndex("created_at"));
Log.d("pid",pid);
results.add("Name: " + name + "\n Price: " + price + "\n Date posted: " + date);
}while (c.moveToNext());
}
}
} catch (SQLiteException se ) {
Log.e(getClass().getSimpleName(), "Could not create or Open the database");
} finally {
if (newDB != null)
newDB.execSQL("DELETE FROM " + tableName);
newDB.close();
}
}
}
Database handler:
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 2;
// Database Name
private static final String DATABASE_NAME = "itemManager";
// table name
public static final String TABLE_ITEM = "item";
// Item Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PRICE = "price";
private static final String KEY_CREATED_AT = "created_at";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_ITEM_TABLE = "CREATE TABLE " + TABLE_ITEM + "("
+ KEY_ID + " INTEGER PRIMARY KEY autoincrement,"
+ KEY_NAME + " TEXT, "
+ KEY_PRICE + " TEXT,"
+ KEY_CREATED_AT + " TEXT" + ")";
db.execSQL(CREATE_ITEM_TABLE);
}
// Upgrading database
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_ITEM);
// Create tables again
onCreate(db);
}
/**
* Storing item details in database
* */
public void addItem(Items item) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, item.getName()); // item name
values.put(KEY_PRICE, item.getPrice()); // item price
values.put(KEY_CREATED_AT, item.getDate()); // Created At
// Inserting Row
db.insert(TABLE_ITEM, null, values);
db.close(); // Closing database connection
}
/**
* Getting item data from database
* */
public List<Items> getAllItems(){
List<Items> itemList = new ArrayList<Items>();
String selectQuery = "SELECT * FROM " + TABLE_ITEM;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// Move to first row
if (cursor.moveToFirst()) {
do {
Items item = new Items();
item.setID(Integer.parseInt(cursor.getString(0)));
item.setName(cursor.getString(1));
item.setPrice(cursor.getString(2));
item.setDate(cursor.getString(2));
// Adding item to list
itemList.add(item);
} while (cursor.moveToNext());
}
// return item list
return itemList;
}
/**
* return true if rows are there in table
* */
public int getRowCount() {
String countQuery = "SELECT * FROM " + TABLE_ITEM;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int rowCount = cursor.getCount();
db.close();
cursor.close();
// return row count
return rowCount;
}
// Updating item
public int updateItem(Items item) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, item.getName());
values.put(KEY_PRICE, item.getPrice());
values.put(KEY_CREATED_AT, item.getDate());
// updating row
return db.update(TABLE_ITEM, values, KEY_ID + " = ?",
new String[] { String.valueOf(item.getID()) });
}
// Deleting item
public void deleteItem(Items item) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_ITEM, KEY_ID + " = ?",
new String[] { String.valueOf(item.getID()) });
db.close();
}
}

Well, don't you delete all the records before closing the database?
} finally {
if (newDB != null)
newDB.execSQL("DELETE FROM " + tableName);
newDB.close();
}
That would explain that behaviour.

How I can start my Android SQLite Application without a Error

I want built a Android Application with a SQLite Database. I have two Java Classes. The First is the Contact Class ans the second the DatabaseHandle class for the operations how add, update etc...
I don't get a error but if I start my Application I become this message ...
Here is my Contact Class
package de.linde.sqlite;
public class Contact {
int _id;
String _name;
String _phone_number;
public Contact(){}
public Contact(int id,String name,String _phone_number){
this._id = id;
this._name = name;
this._phone_number = _phone_number;
}
public Contact(String name,String _phone_number){
this._name = name;
this._phone_number = _phone_number;
}
public int getID(){
return this._id;
}
public void setID(int id){
this._id = id;
}
public String getName(){
return this._name;
}
public void setName(String name){
this._name = name;
}
public String getPhoneNumber(){
return this._phone_number;
}
public void setPhoneNumber(String phone_number){
this._phone_number = phone_number;
}
}
Here is my DatabaseHandler Class
package de.linde.sqlite;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHandler extends SQLiteOpenHelper {
//Datenbank version
private static final int DATABASE_VERSION = 1;
//Datenbankname
private static final String DATABASE_NAME = "contactsManager";
//Tabellenname
private static final String TABLE_CONTACTS = "contacts";
//Tabellenspalten
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PH_NO = "phone_number";
public DatabaseHandler(Context context){
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db){
String CREATE_CONTACTS_TABLE = "CREATE TABLE" + TABLE_CONTACTS + "("
+ KEY_ID + "INTEGER PRIMARY KEY," + KEY_NAME + "TEXT,"
+ KEY_PH_NO + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){
db.execSQL("DROP TABLE IF EXISTS" + TABLE_CONTACTS);
onCreate(db);
}
public void addContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName()); // Contact Name
values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone Number
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
db.close(); // Closing database connection
}
public Contact getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
// return contact
return contact;
}
public List<Contact> getAllContacts() {
List<Contact> contactList = new ArrayList<Contact>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Contact contact = new Contact();
contact.setID(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setPhoneNumber(cursor.getString(2));
// Adding contact to list
contactList.add(contact);
} while (cursor.moveToNext());
}
// return contact list
return contactList;
}
public int getContactsCount() {
String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
public int updateContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName());
values.put(KEY_PH_NO, contact.getPhoneNumber());
// updating row
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
}
public void deleteContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
db.close();
}
}
Here is my MainActivity
package de.linde.sqlite;
import java.util.List;
import android.os.Bundle;
import android.util.Log;
import android.app.Activity;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseHandler db = new DatabaseHandler(this);
Log.d("Insert: ", "Inserting ..");
db.addContact(new Contact("Wladimir","024324324"));
db.addContact(new Contact("Max","0324324324"));
db.addContact(new Contact("Benny","0324324"));
db.addContact(new Contact("derSchwarze","051324324"));
Log.d("Reading: ","Reading all Contacts..");
List<Contact> contacts = db.getAllContacts();
for (Contact cn : contacts) {
String log = "Id: " + cn.getID() + " ,Name: " + cn.getName() + " ,Phone: " + cn.getPhoneNumber();
Log.d("Name: ", log);
}
}
}
My activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</RelativeLayout>
What I make wrong :(

Add spaces between the values that you add to CREATE_CONTACTS_TABLE and the concatenated string, so you build a valid table creation string:
"CREATE TABLE " + TABLE_CONTACTS + " (" + KEY_ID + " INTEGER PRIMARY KEY, " + KEY_NAME + " TEXT, " + KEY_PH_NO + " TEXT)";
You'll need to uninstall the app from the phone/emulator and then run it again to make the database to be recreated again.
The same thing is valid for the String in the onUpgrade method:
"DROP TABLE IF EXISTS " + TABLE_CONTACTS