Develop Reference

DataBase access using Loader

I have made a local database.I have accessing it using diffrent methods but i think CursorLoader is the efficient way to access it.But i don't know know how to do it.Can anyone help?Here is my code
Main Activity
public class Main2Activity extends AppCompatActivity implements
LoaderManager.LoaderCallbacks<Cursor>{
TextView t1;
RecyclerView mRecyclerView;
RecyclerAdapter recyclerAdapter;
RecyclerAdapter adapter;
List<Info> infoList;
String arrr;
int ar;
int Loader_id=1;
private RecyclerView.LayoutManager mLayoutManager;
SimpleCursorAdapter simpleCursorAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
final DatabaseHandler db = new DatabaseHandler(this);
List<Info> infos = db.getAllInfo();
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.addItemDecoration(new SimpleDivider(Main2Activity.this));
recyclerAdapter = new RecyclerAdapter(this, infos);
mRecyclerView.setAdapter(recyclerAdapter);
}
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return null;
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
}
#Override
public void onLoaderReset(Loader<Cursor> loader) {
}
}
DataBaseHandler
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "Dispalymanager";
private static final String TABLE = "contacts";
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_AGE = "age";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_TABLE = "CREATE TABLE " + TABLE + "(" + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT," + KEY_AGE + " TEXT" + ")";
db.execSQL(CREATE_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE);
onCreate(db);
}
void addInfo(Info info) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, info.getName());
values.put(KEY_AGE, info.getAge());
db.insert(TABLE, null, values);
db.close();
}
Info getinfo(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE, new String[]{KEY_ID, KEY_NAME, KEY_AGE}, KEY_ID + "=?",
new String[]{String.valueOf(id)}, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Info info = new Info(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
return info;
}
public List<Info> getAllInfo() {
List<Info> infoList = new ArrayList<Info>();
String selectQuery = "SELECT * FROM " + TABLE;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
Info contact = new Info();
contact.setID(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setPhoneNumber(cursor.getString(2));
infoList.add(contact);
} while (cursor.moveToNext());
}
return infoList;
}
public int updateInfo(Info info) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, info.getName());
values.put(KEY_AGE, info.getAge());
return db.update(TABLE, values, KEY_ID + " = ?", new String[]{String.valueOf(info.getID())});
}
public void deleteInfo(Info contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE, KEY_NAME + " = ?", new String[]{String.valueOf(contact.getName())});
db.close();
}
public int getInfoCount() {
String countQuery = "SELECT * FROM " + TABLE;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int count = cursor.getCount();
cursor.close();
return count;
}
boolean deleteitem(int id){
SQLiteDatabase db = this.getWritableDatabase();
db.execSQL("delete from "+TABLE+" where "+KEY_ID+" ="+id);
return true;
}
}

Interchange ids of android database

How to go about if i want to interchange the contents of my android data base as shown below:
before
1 hello world
2 Android Nougat
after
1 Android Nougat
2 hello world

You don't need to change the positions in Database. You need to add additional int value to a database (not id). And change this value according to a new position. For first object you make it 2; for a second - 1. And when you retrieve data from your database you just sort it according to this value.
Example
String orderBy = "POSITION ASC";
Cursor cursor = database.query(TABLE_NAME, logTableColumns, null, null,
null, null, orderBy);

public class QueueDatabase extends SQLiteOpenHelper {
public QueueDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public static final int DATABASE_VERSION = 1;
// Database Name
public static final String DATABASE_NAME = "queue.sqlite";
//Table names
public static final String TABLE_QUEUE = "Queue";
public static final String KEY_ID = "id";
public static final String KEY_SNAME = "key_sname";
public static final String KEY_ANAME = "key_aname";
public static final String KEY_URL = "key_url";
public static final String KEY_ORDER = "key_order";
public static final String CREATE_TABLE_QUEUE= "CREATE TABLE IF NOT EXISTS "
+ TABLE_QUEUE
+ "("
+ KEY_ID
+ " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ KEY_SNAME
+ " TEXT,"
+ KEY_ANAME
+ " TEXT,"
+ KEY_URL
+ " TEXT,"
+ KEY_ORDER
+ " TEXT "
+")";
public long insertQueue(ArrayList<Music> mTaskArr)
{
long row_id = 0;
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
for(int i = 0;i<mTaskArr.size() ;i++) {
values.put(KEY_SNAME, mTaskArr.get(i).getTitle());
values.put(KEY_ANAME, mTaskArr.get(i).getArtist());
values.put(KEY_URL, mTaskArr.get(i).getUrl());
row_id = db.insert(TABLE_QUEUE, null, values);
}
db.close();
return row_id;
}
public void updateOrder(long rowID, int newPos) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(KEY_ORDER, newPos);
db.update(TABLE_QUEUE, cv, KEY_ID + "=" + rowID, null);
}
public boolean updateQueue (Integer id, String S, String A, String U) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(KEY_SNAME,S);
contentValues.put(KEY_ANAME,A);
contentValues.put(KEY_URL,U);
db.update(TABLE_QUEUE, contentValues, "id = ? ", new String[] { Integer.toString(id) } );
return true;
}
public void dropTable() {
SQLiteDatabase db = this.getWritableDatabase();
String sql = "drop table " + TABLE_QUEUE;
try {
db.execSQL(sql);
} catch (SQLException e) {
System.out.println(e);
}
}
public ArrayList<Music> getAllQueue() {
ArrayList<Music> ar = new ArrayList<Music>();
String selectQuery = "SELECT * FROM " + TABLE_QUEUE;
//Log.d("QUERY",""+selectQuery);
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, null);
if (c.moveToFirst()) {
do {
Music r = new Music();
r.setId(c.getInt(c.getColumnIndex(KEY_ID)));
r.setTitle( c.getString(c.getColumnIndex(KEY_SNAME)));
r.setArtist( c.getString(c.getColumnIndex(KEY_ANAME)));
r.setUrl(c.getString(c.getColumnIndex(KEY_URL)));
ar.add(r);
} while (c.moveToNext());
}
db.close();
return ar;
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE_QUEUE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
onCreate(db);
}
public void arrange() {
SQLiteDatabase db = this.getWritableDatabase();
String[] rank = new String[]{ QueueDatabase.KEY_ID };
Cursor c = db.query(QueueDatabase.TABLE_QUEUE, rank, null, null, null, null, QueueDatabase.KEY_ORDER+" ASC");
}
}
this is how u enter data in database:
q.add(new Music(T, U, A));
qd.insertQueue(q);

Android SQLite Table Creation Error

I have my code to create SQLite database, the code create database but does not create any table. I went through some of the similar errors that others had before, I couldn't find any error. Could anyone help me.
Here is my code
public class DBHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "swahilComm.db";
public static final String COUNTRY_TABLE = "countries";
public static final String COUNTRY_ID = "id";
public static final String COUNTRY_NAME = "country";
public static final String PROVINCE_TABLE = "province";
public static final String PROVINCE_ID = "id";
public static final String PROVINCE_NAME = "province";
public static final String CREATE_TABLE_PROVINCE = "CREATE TABLE " + PROVINCE_TABLE + "("
+ PROVINCE_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ PROVINCE_NAME + " TEXT );";
public static final String CREATE_COUNTRY_TABLE = "CREATE TABLE " + COUNTRY_TABLE + "("
+ COUNTRY_ID + " INTEGET PRIMARY KEY AUTOINCREMENT,"
+ COUNTRY_NAME + " TEXT );";
public DBHelper(Context context ) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
Log.d("Database Operation", "Database Created...");
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE_PROVINCE);
db.execSQL(CREATE_COUNTRY_TABLE);
Log.d("Database Operation", "Tables Created...");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed, all data will be gone
db.execSQL("DROP TABLE IF EXISTS " + PROVINCE_TABLE);
db.execSQL("DROP TABLE IF EXISTS " + COUNTRY_TABLE);
// Create tables again
onCreate(db);
}
//Delete all data in the table
public void DeleteCountry() {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(COUNTRY_TABLE, null, null);
db.close(); // Closing database connection
}
//Delete all data in the Province table
public void DeleteProvice() {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(PROVINCE_TABLE, null, null);
db.close(); // Closing database connection
}
//Insert country records
public int insertCountry(Country country) {
// TODO Auto-generated method stub
//Integer noProvince = getProvinceCount();
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COUNTRY_ID, country.getId());
values.put(COUNTRY_NAME, country.getCountry());
// Inserting Row
long country_Id = db.insert(COUNTRY_TABLE, null, values);
db.close(); // Closing database connection
return (int) country_Id;
}
//Insert province records
public int insertProvince(Province province) {
// TODO Auto-generated method stub
//Integer noProvince = getProvinceCount();
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(PROVINCE_ID, province.getId());
values.put(PROVINCE_NAME, province.getProvince());
// Inserting Row
long province_Id = db.insert(PROVINCE_NAME, null, values);
db.close(); // Closing database connection
return (int) province_Id;
}
//Retrieve all records and populate into List<Country>
//This method allow you to retrieve more fields/information into List.
public List<Country> getAllCountry() {
SQLiteDatabase db = this.getReadableDatabase();
String selectQuery = "SELECT " +
COUNTRY_ID + "," +
COUNTRY_NAME +
" FROM " + COUNTRY_TABLE;
List<Country> countryList = new ArrayList<Country>() ;
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Country country = new Country();
country.setId(cursor.getString(cursor.getColumnIndex(COUNTRY_ID)));
country.setCountry(cursor.getString(cursor.getColumnIndex(COUNTRY_NAME)));
countryList.add(country);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return countryList;
}
//Retrieve all records and populate into List<Province>
//This method allow you to retrieve more fields/information into List.
public List<Province> getAll() {
SQLiteDatabase db = this.getReadableDatabase();
String selectQuery = "SELECT " +
PROVINCE_ID + "," +
PROVINCE_NAME +
" FROM " + PROVINCE_TABLE;
List<Province> provinceList = new ArrayList<Province>() ;
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Province province = new Province();
province.setId(cursor.getString(cursor.getColumnIndex(PROVINCE_ID)));
province.setProvince(cursor.getString(cursor.getColumnIndex(PROVINCE_NAME)));
provinceList.add(province);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return provinceList;
}
//Retrieve all records and populate into List<String>
public List<String> getAllStringCountry() {
SQLiteDatabase db = this.getReadableDatabase();
String selectQuery = "SELECT " +
COUNTRY_ID + "," +
COUNTRY_NAME +
" FROM " + COUNTRY_TABLE;
List<String> countryList = new ArrayList<String>() ;
Cursor cursor = db.rawQuery(selectQuery, null);
Integer i=0;
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
countryList.add(i,cursor.getString(cursor.getColumnIndex(COUNTRY_NAME)));
i+=1;
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return countryList;
}
//Retrieve all records and populate into List<String>
public List<String> getAll_Simple() {
SQLiteDatabase db = this.getReadableDatabase();
String selectQuery = "SELECT " +
PROVINCE_ID + "," +
PROVINCE_NAME +
" FROM " + PROVINCE_TABLE;
List<String> provinceList = new ArrayList<String>() ;
Cursor cursor = db.rawQuery(selectQuery, null);
Integer i=0;
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
provinceList.add(i,cursor.getString(cursor.getColumnIndex(PROVINCE_NAME)));
i+=1;
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return provinceList;
}
}
This is the the Activity Class
public class Register extends AppCompatActivity {
DBHelper repo = new DBHelper(this);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
countries = getResources().getStringArray(R.array.countries);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, countries);
autoCompleteTextView.setAdapter(adapter);
insertDummyData();
loadProvince_Simple();
}
// This class insert data
private void insertDummyData(){
repo.DeleteProvice();
int i = 1;
String[] provinces = {"Prince Edward Island", "Quebec", "Saskatchewan", "Yukon","Northwest Territories", "Ontario", "Nunavut", "Nova Scotia", "Alberta", "British Columbia", "Manitoba", "New Brunswick", "Newfoundland and Labrador"};
for(int j=0; j < provinces.length; j++) {
Province province = new Province();
province.setId(Integer.toString(i));
province.setProvince(provinces[j]);
repo.insertProvince(province);
i++;
}
}
//This is the arrayadapter binding method as you can see
private void loadProvince_Simple(){
ArrayAdapter<String> spinnerAdapter;
DBHelper db = new DBHelper(getApplicationContext());
List<String> provinces = db.getAll_Simple();
spinnerAdapter = new ArrayAdapter<String>(Register.this,
android.R.layout.simple_spinner_item, provinces);
prov_spinner.setAdapter(spinnerAdapter);
spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
}
}

Read my comments below:
// TRY TO REMOVE THE SPACE BETWEEN "TEXT" TO THE "(" IN THE LAST LINE OF BOTH STRINGS
public static final String CREATE_TABLE_PROVINCE = "CREATE TABLE " + PROVINCE_TABLE + "("
+ PROVINCE_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ PROVINCE_NAME + " TEXT );";
// YOU WROTE "INTEGET"
public static final String CREATE_COUNTRY_TABLE = "CREATE TABLE " + COUNTRY_TABLE + "("
+ COUNTRY_ID + " INTEGET PRIMARY KEY AUTOINCREMENT,"
+ COUNTRY_NAME + " TEXT );";

Android NullpointerException when trying to retrieve data from SQLiteOpenHelper

I get following error in logcat when trying to retrieve all SQLite rows from SQLiteOpenHelper.
Caused by: java.lang.NullPointerException at notes.dev.tauhid.com.mynotes.fragment.MyNotes.onCreateView(MyNotes.java:89)
My SQLiteOpenHelper class is
public class DatabaseHandlerNotes extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "my_notes";
private static final String TABLE_NOTES = "my_notes_table";
private static final String KEY_ID = "id";
private static final String KEY_TITLE = "title";
private static final String KEY_DESCRIPTION = "phone_number";
private static final String KEY_DATE = "date";
private static final String KEY_REMINDER_DATE = "reminder_date";
private static final String KEY_CATEGORY = "category";
private static final String KEY_LOCK = "lock";
public DatabaseHandlerNotes(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_NOTES_TABLE = "CREATE TABLE " + TABLE_NOTES + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_TITLE + " TEXT,"
+ KEY_DESCRIPTION + " TEXT," + KEY_DATE + " INTEGER," + KEY_REMINDER_DATE + " INTEGER," + KEY_CATEGORY + " INTEGER," + KEY_LOCK + " TEXT" + ")";
db.execSQL(CREATE_NOTES_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NOTES);
onCreate(db);
}
public void addNote(Note note) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_TITLE, note.getTitle());
values.put(KEY_DESCRIPTION, note.getDescription());
values.put(KEY_DATE, note.getDate());
values.put(KEY_REMINDER_DATE, note.getReminderDate());
values.put(KEY_CATEGORY, note.getCategory());
values.put(KEY_LOCK, note.getLock());
db.insert(TABLE_NOTES, null, values);
db.close();
}
public Note getNote(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_NOTES, new String[] { KEY_ID,
KEY_TITLE, KEY_DESCRIPTION, KEY_DATE, KEY_REMINDER_DATE, KEY_CATEGORY }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Note note = new Note(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2), Integer.parseInt(cursor.getString(3)), Integer.parseInt(cursor.getString(4)), Integer.parseInt(cursor.getString(5)), cursor.getString(6));
return note;
}
public List<Note> getAllNotes() {
List<Note> noteList = new ArrayList<Note>();
String selectQuery = "SELECT * FROM " + TABLE_NOTES;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
Note note = new Note();
note.setID(Integer.parseInt(cursor.getString(0)));
note.setTitle(cursor.getString(1));
note.setDescription(cursor.getString(2));
note.setDate(Integer.parseInt(cursor.getString(3)));
note.setReminderDate(Integer.parseInt(cursor.getString(4)));
note.setCategory(Integer.parseInt(cursor.getString(5)));
note.setLock(cursor.getString(6));
noteList.add(note);
} while (cursor.moveToNext());
}
return noteList;
}
public int updateNote(Note note) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_TITLE, note.getTitle());
values.put(KEY_DESCRIPTION, note.getDescription());
values.put(KEY_DATE, note.getDate());
values.put(KEY_REMINDER_DATE, note.getReminderDate());
values.put(KEY_CATEGORY, note.getCategory());
values.put(KEY_LOCK, note.getLock());
// updating row
return db.update(TABLE_NOTES, values, KEY_ID + " = ?",
new String[] { String.valueOf(note.getID()) });
}
public void deleteNote(Note note) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_NOTES, KEY_ID + " = ?",
new String[] { String.valueOf(note.getID()) });
db.close();
}
public int getNotesCount() {
String countQuery = "SELECT * FROM " + TABLE_NOTES;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
return cursor.getCount();
}
And in my Fragment class where i want to retrieve all rows
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
databaseHandlerNote = new DatabaseHandlerNotes(getActivity());
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.my_notes_fragment_notes, container, false);
ListView allNotes = (ListView) rootView.findViewById(R.id.my_notes_all);
List<Note> noteList = databaseHandlerNote.getAllNotes();
for (Note note : noteList) {
Note noteEach = new Note();
noteEach.setID(note.getID());
noteEach.setTitle(note.getTitle());
noteEach.setDescription(note.getDescription());
noteEach.setCategory(note.getCategory());
noteEach.setLock(note.getLock());
noteEach.setDate(note.getDate());
noteEach.setReminderDate(note.getReminderDate());
this.customNotesList.add(noteEach);
}
customNoteAdapter = new CustomNoteAdapter(getActivity(), customNotesList);
allNotes.setAdapter(customNoteAdapter);
return rootView;
}
Here 89th line in onCreateView is
List<Note> noteList = databaseHandlerNote.getAllNotes();
Thanks in advance.

The problem is that onActivityCreated() is called after onCreateView(). Thus your databaseHandlerNote hasn't been created yet, and trying to use it will result in a NullPointerException.
Check out the Fragment lifecycle diagram from the Fragment documentation.

From Fragment lifecircle, onCreateView() is called before onActivityCreated(), so when you call:
List<Note> noteList = databaseHandlerNote.getAllNotes();
in onCreateView(), databaseHandlerNote is not yet created, then you got exception. So solution is that:
move your:
databaseHandlerNote = new DatabaseHandlerNotes(getActivity());
from onActivityCreated() to onCreate()

How to insert data in SQLite db in Android?

I'm implementing SQLite db in my android application i want retrieve data from JSON and store in into SQLite db .I saw one of the example of using SQLite but I'm using different column name wchi is store into SQLite db .
But when i run the app I'm getting Error like =
((1) table contacts has no column named cost ,
Error inserting phone_number=9533333333 cost=46456 name=Karthik ,
android.database.sqlite.SQLiteException: table contacts has no column named cost (code 1): , while compiling: INSERT INTO contacts(phone_number,cost,name) VALUES (?,?,?))
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 = "contactsManager";
// Contacts table name
private static final String TABLE_CONTACTS = "contacts";
// Contacts Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_COST = "cost";
private static final String KEY_PH_NO = "phone_number";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
+ KEY_COST + " TEXT,"
+ KEY_PH_NO + " 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_CONTACTS);
// Create tables again
onCreate(db);
}
/**
* All CRUD(Create, Read, Update, Delete) Operations
*/
// Adding new contact
void addContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact._name); // Contact Name
values.put(KEY_COST, contact._cost); // Contact Phone
values.put(KEY_PH_NO, contact._mobile); //Contact phone no
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
db.close(); // Closing database connection
}
// Getting single contact
Contact getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_COST, 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),cursor.getString(3));
// return contact
return contact;
}
// Getting All Contacts
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.set_id(Integer.parseInt(cursor.getString(0)));
contact.set_name(cursor.getString(1));
contact.set_cost(cursor.getString(2));
contact.set_mobile(cursor.getString(3));
contactList.add(contact);
} while (cursor.moveToNext());
}
// return contact list
return contactList;
}
// Updating single contact
public int updateContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.get_name());
values.put(KEY_COST, contact.get_cost());
values.put(KEY_PH_NO, contact.get_mobile());
// updating row
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[] { String.valueOf(contact.get_id()) });
}
// Deleting single contact
public void deleteContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
new String[] { String.valueOf(contact.get_id()) });
db.close();
}
// Getting contacts Count
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();
}
}

Change this line
private static final int DATABASE_VERSION = 1;
to this
private static final int DATABASE_VERSION = 2;
And check your work again.

Try clear your app data then rerun the app, you may have had a different column before and run the app once (meaning the create table would not be called again).