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How to get data from a sqllite database and store it in ListView

I have a data base I need to read data from it and view it in a list view it contain some tables from them a table named "main_categories" which has one field called "category_name" which is the primary key
this is the DataAdapter:
public DataAdapter(Context context) {
this.mContext = context;
mDbHelper = new DataBaseHelper(mContext);
}
public DataAdapter createDatabase() throws SQLException {
try {
mDbHelper.createDataBase();
} catch (IOException mIOException) {
Log.e(TAG, mIOException.toString() + " UnableToCreateDatabase");
throw new Error("UnableToCreateDatabase");
}
return this;
}
public DataAdapter open() throws SQLException {
try {
mDbHelper.openDataBase();
mDbHelper.close();
mDb = mDbHelper.getReadableDatabase();
} catch (SQLException mSQLException) {
Log.e(TAG, "open >>" + mSQLException.toString());
throw mSQLException;
}
return this;
}
public void close() {
mDbHelper.close();
}
public Cursor getTestData() {
try {
String sql = "SELECT * FROM myTable";
Cursor mCur = mDb.rawQuery(sql, null);
if (mCur != null) {
mCur.moveToNext();
}
return mCur;
} catch (SQLException mSQLException) {
Log.e(TAG, "getTestData >>" + mSQLException.toString());
throw mSQLException;
}
}
}
and this is the DataBaseHelper:
public class DataBaseHelper extends SQLiteOpenHelper
{
private static String TAG = "DataBaseHelper"; // Tag just for the LogCat window
//destination path (location) of our database on device
private static String DB_PATH = "";
private static String DB_NAME ="my_knowledge";// Database name
private SQLiteDatabase mDataBase;
private final Context mContext;
public DataBaseHelper(Context context)
{
super(context, DB_NAME, null, 1);// 1? Its database Version
if(android.os.Build.VERSION.SDK_INT >= 17){
DB_PATH = context.getApplicationInfo().dataDir + "/databases/";
}
else
{
DB_PATH = context.getApplicationInfo().dataDir + "/databases/";
}
this.mContext = context;
}
public void createDataBase() throws IOException
{
//If the database does not exist, copy it from the assets.
boolean mDataBaseExist = checkDataBase();
if(!mDataBaseExist)
{
this.getReadableDatabase();
this.close();
try
{
//Copy the database from assests
copyDataBase();
Log.e(TAG, "createDatabase database created");
}
catch (IOException mIOException)
{
throw new Error("ErrorCopyingDataBase");
}
}
}
//Check that the database exists here: /data/data/your package/databases/Da Name
private boolean checkDataBase()
{
File dbFile = new File(DB_PATH + DB_NAME);
//Log.v("dbFile", dbFile + " "+ dbFile.exists());
return dbFile.exists();
}
//Copy the database from assets
private void copyDataBase() throws IOException
{
InputStream mInput = mContext.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream mOutput = new FileOutputStream(outFileName);
byte[] mBuffer = new byte[1024];
int mLength;
while ((mLength = mInput.read(mBuffer))>0)
{
mOutput.write(mBuffer, 0, mLength);
}
mOutput.flush();
mOutput.close();
mInput.close();
}
//Open the database, so we can query it
public boolean openDataBase() throws SQLException
{
String mPath = DB_PATH + DB_NAME;
//Log.v("mPath", mPath);
mDataBase = SQLiteDatabase.openDatabase(mPath, null, SQLiteDatabase.CREATE_IF_NECESSARY);
//mDataBase = SQLiteDatabase.openDatabase(mPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS);
return mDataBase != null;
}
#Override
public synchronized void close()
{
if(mDataBase != null)
mDataBase.close();
super.close();
}
#Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
}
#Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
}
}
and this is the main activity for now:
public class MainActivity extends AppCompatActivity {
SQLiteDatabase sqLiteDatabase;
private static String DB_NAME ="my_knowledge"; // Database name
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView list = findViewById(R.id.main_list);
DataAdapter mDbHelper = new DataAdapter(this);
mDbHelper.createDatabase();
mDbHelper.open();
Cursor testdata = mDbHelper.getTestData();
mDbHelper.close();
}
}
I want to know a way to store the data in the tables of the array (for example "main_categories") and view them with the list view

Depending on your table column type
List<String> temp;
testdata.moveToFirst();
do {
temp.add(testdata.getString(0));
} while (testdata.moveToNext());
Your cursor testdata has the first row in testdata.moveToFirst(); and each column is associated with column index i.e. 0, 1 etc.
testdata.moveToNext(); will have successive rows.

A couple of things:
First of, I would consider adding a query method to your DataBaseHelper class instead of using a rawQuery, something like:
Cursor query(String table, String[] projection, String where, String orderBy) {
return getReadableDatabase().query(table, projection, where, null, null, null, orderBy);
}
You can call the query method inside mDbHelper.getTestData() and use the Cursor object to populate your list.
Take a look at using a Cursor Loader?
to do get the data out of the cursor and into your adapter.

onUpgrade() and onCreate() method do not invoke when creating a new version of database in SQLiteOpenHelper

I am trying to create a new version of database in my android app. But although I change the version of database from previous version (2) to a new version (3) it doesn't invoke onUpgrade() and onCreate() . It just invoke three times the constructor. I do not understand why constructor invoked three times and also why onUpgrade() and onCreate() did not invoke?
I also tried with new database version code but result is same.
Here is my code.
public class DatabaseHelper extends SQLiteOpenHelper {
private static String PACKAGE_NAME;
private static String DB_PATH;
private static String DB_NAME = "mydata.db";
private SQLiteDatabase myDataBase;
private final Context myContext;
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, 3);
this.myContext = context;
Log.e("UPDATED3", "CONSTRUCTOR");
PACKAGE_NAME = myContext.getPackageName();
DB_PATH = "/data/data/" + PACKAGE_NAME + "/databases/";
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
// do nothing - database already exist
} else {
// By calling this method and empty database will be created into
// the default system path
// of your application so we are gonna be able to overwrite that
// database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
// database does't exist yet.
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
private void copyDataBase() throws IOException {
// Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
// Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
#Override
public synchronized void close() {
if (myDataBase != null)
myDataBase.close();
super.close();
}
#Override
public void onCreate(SQLiteDatabase db) {
Log.e("UPDATED3", "ONCREATE");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.e("UPDATED3", "UPDATED THE DATABASE");
}
}
I use my database this(showing below) way in any activity.
DatabaseHelper databaseHelper = new DatabaseHelper(getApplicationContext());
try {
databaseHelper.createDataBase();
databaseHelper.openDataBase();
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Error: " + e.getMessage(),
Toast.LENGTH_LONG).show();
e.printStackTrace();
}

Empty database being created but copying of tables from Assets not happening

I have packaged a database with my application, and I can see in my File Explorer that the databases folder along with the workoutsDatabase.sqlite file is being created. When I look at the contents of the database, though, the only table in there is the android_metadata table. I have been searching for hours and have seen many people with similar problems, however, I cannot seem to figure out the correct solution.
Can anyone spot why the tables dont seem to copy over? I have validated the workoutsDatabase.sqlite in my assets folder DOES contain the table "workout" and it does have data in it.
WorkoutsDatabaseHelper
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteStatement;
import android.util.Log;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class WorkoutsDatabaseHelper extends SQLiteOpenHelper {
private String DATABASE_PATH = "/data/data/com.rcd.myworkouts/databases/";
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "workoutsDatabase.sqlite";
private static final String TABLE_WORKOUTS = "workouts";
private static final String KEY_ID = "_id";
private static final String KEY_WORKOUT_NAME = "workout_name";
private static final String KEY_LAST_NAME = "last_name";
private static final String KEY_FIRST_NAME = "first_name";
private static final String KEY_MIDDLE_NAME = "middle_name";
private static final String KEY_DESCRIPTION = "description";
private static final String KEY_DATE_ADDED = "date_added";
private static final String KEY_WORKOUT = "workout";
private static final String KEY_MEASUREMENT = "measurement";
private static final String KEY_PHOTO = "photo";
private SQLiteDatabase myDatabase;
private final Context myContext;
public WorkoutsDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.myContext = context;
}
// Creates a empty database on the system and rewrites it with your own database.
public void createDatabase() throws IOException {
boolean dbExist = checkDatabase();
SQLiteDatabase db_Read = null;
if(dbExist) {
// Do nothing - database already exist
} else {
//By calling this method an empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
db_Read = getReadableDatabase();
db_Read.close();
try {
copyDatabase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
//Check if the database already exist to avoid re-copying the file each time you open the application.
//#return true if it exists, false if it doesn't
private boolean checkDatabase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DATABASE_PATH + DATABASE_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
} catch(SQLiteException e) {
// Database doesn't exist yet
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDatabase() throws IOException {
getWritableDatabase();
Log.d("Database", "New database is being copied to device!");
try
{
// Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DATABASE_NAME);
// transfer bytes from the inputfile to the
// Path to the just created empty db
String outFileName = DATABASE_PATH + DATABASE_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// Transfer bytes form the inputfile to the output file
byte[] buffer = new byte[1024];
int length;
while((length = myInput.read(buffer)) > 0)
{
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
Log.i("Database", "New database has been copied to device!");
}
catch(IOException e)
{
e.printStackTrace();
}
}
protected Boolean openDatabase() {
if(checkDatabase())
{
// Open the database
String myPath = DATABASE_PATH + DATABASE_NAME;
try
{
Log.i("Database", "Trying to Open Database!");
if(myDatabase != null)
{
if(!myDatabase.isOpen())
{
Log.i("Database", "Database is closed now opening it!");
myDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
else
{
Log.i("Database", "Database is already Open!");
}
Log.i("Database", "Database is Opened successfully in OPEN_READWRITE Mode !");
return true;
}
else
{
myDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
Log.i("Database", "Database is Opened successfully in OPEN_READWRITE Mode !");
return true;
}
}
catch(Exception e)
{
Log.e("Database", "Some error occured while opening Database Error:" + e.getMessage());
myDatabase = null;
return false;
}
}
else
try {
copyDatabase();
Log.d("WorkoutsDatabaseHelper.java", "Copy Database..");
} catch (IOException e) {
throw new Error("Error copying database");
}
return false;
}
#Override
public synchronized void close() {
if(myDatabase != null)
myDatabase.close();
super.close();
}
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}

how to make MyDBHelper As Global Variable?

This is my DataBaseHelper.java
package com.example.abc2;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
public class DataBaseHelper extends SQLiteOpenHelper{
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.example.abc2/databases/";
private static String DB_NAME = "DB_BusData";
private SQLiteDatabase myDataBase;
private final Context myContext;
/**
* Constructor
* Takes and keeps a reference of the passed context in order to access to the application assets and resources.
* #param context
*/
public DataBaseHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
/**
* Creates a empty database on the system and rewrites it with your own database.
* */
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* #return true if it exists, false if it doesn't
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
#Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
// Add your public helper methods to access and get content from the database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
// to you to create adapters for your views.
}
MainActivity.java
public void DatabaseConn(){
DataBaseHelper myDbHelper = new DataBaseHelper(this.getApplicationContext());
myDbHelper = new DataBaseHelper(this);
try {
myDbHelper.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
myDbHelper.openDataBase();
}catch(SQLException sqle){
throw sqle;
}
SQLiteDatabase db = myDbHelper.getReadableDatabase();
//SQLiteDatabase db = SQLiteDatabase.openDatabase("/data/data/com.example.abc2/databases/DB_BusData", null, 0);
Cursor c = db.rawQuery("SELECT * FROM Tbl_Driver", null);
if(c.moveToFirst()) {
String username = c.getString(c.getColumnIndex("Driver_Code")).trim();
String password = c.getString(c.getColumnIndex("Driver_Name")).trim();
Log.d(null, username);
}
db.close();
}
Any Idea to make my myDbHelper as global variable, otherwise every function i want to call the database i need to declare it, it is inconvenience.

Just add this
DataBaseHelper myDbHelper = new DataBaseHelper(this.getApplicationContext());
Over onCreate in your MainActivity, and remove it from public void DatabaseConn(){.

Create a Singleton Database class:
public class Database extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "yourDatabaseName";
//Declare a String for each Table name
public static final String TABLE_NAME1 = "tableName1";
public static final String TABLE_NAME2 = "tableName2";
//Declare a SQL string for create each table
private static final String CREATE_TABLE1 =
"CREATE TABLE if not exists " + TABLE_NAME1 ..............";
private static final String CREATE_TABLE2 =
"CREATE TABLE if not exists " + TABLE_NAME2 .................";
private static Database Singleton = null;
private Context context;
private static SQLiteDatabase Db;
private Database(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.context = context;
}
public static synchronized Database getInstance(Context c){
if(Singleton == null) {
Singleton = new Database(c.getApplicationContext());
Db = Singleton.getWritableDatabase();
}
return Singleton;
}
public SQLiteDatabase getDatabase() {
return Db;
}
public synchronized void close() {
if (Singleton != null && Db.isOpen()) Db.close();
}
#Override
protected void finalize() throws Throwable {
try{
close();
}
finally{
super.finalize();
}
#Override
public void onCreate(SQLiteDatabase db) {
//Create Tables
db.execSQL(CREATE_TABLE1);
db.execSQL(CREATE_TABLE2);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
When you need a database object:
SQLiteDatabase Db = Database.getInstance(context).getDatabase();

Database onUpgrade method is never called

I'm trying to upgrade my database from version 1 to version 2. I'm assigning DATABASE_VERSION = 2 (first version was assigned too) but onUpgrade never called.
May be there is an obvious mistake in the code, but I can't see it beacause I'm trying to solve this problem for a long time.
Here is the code of database helper class:
public class DatabaseHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 2;
public static String DB_PATH;
public static String DB_NAME = "db.sqlite3";
public SQLiteDatabase database;
public final Context context;
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DATABASE_VERSION);
this.context = context;
File direct = new File(Environment.getExternalStorageDirectory()
+ "/.test");
if (!direct.exists()) {
if (direct.mkdir())
;
}
DB_PATH = Environment.getExternalStorageDirectory().getPath()
+ "/.test/";
}
public void createDataBase() {
boolean dbExist = checkDataBase();
if (!dbExist) {
try {
copyDataBase();
} catch (IOException e) {
Log.e(this.getClass().toString(), "Copying error");
throw new Error("Error copying database!");
}
}
}
private boolean checkDataBase() {
SQLiteDatabase checkDb = null;
try {
String path = DB_PATH + DB_NAME;
checkDb = SQLiteDatabase.openDatabase(path, null,
SQLiteDatabase.OPEN_READONLY);
} catch (SQLException e) {
Log.e(this.getClass().toString(), "Error while checking db");
}
if (checkDb != null) {
checkDb.close();
}
return checkDb != null;
}
private void copyDataBase() throws IOException {
InputStream externalDbStream = context.getAssets().open(
"databases/" + DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream localDbStream = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int bytesRead;
while ((bytesRead = externalDbStream.read(buffer)) > 0) {
localDbStream.write(buffer, 0, bytesRead);
}
localDbStream.close();
externalDbStream.close();
}
public SQLiteDatabase openDataBase() throws SQLException {
String path = DB_PATH + DB_NAME;
if (database == null) {
createDataBase();
database = SQLiteDatabase.openDatabase(path, null,
SQLiteDatabase.OPEN_READONLY);
}
return database;
}
// some unimportant methods
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w("myLogs", " --- onUpgrade database --- ");
}
In Activity I call database like this:
DatabaseHelper dbOpenHelper = new DatabaseHelper(this);
SQLiteDatabase database = dbOpenHelper.openDataBase();
Where is my mistake?
Help, please.
UPD: database.getVersion() returns 0
Updated openDataBase() method (it's working):
public SQLiteDatabase openDataBase() throws SQLException {
String path = DB_PATH + DB_NAME;
if (database == null) {
createDataBase();
database = SQLiteDatabase.openDatabase(path, null,
SQLiteDatabase.OPEN_READWRITE);
this.getWritableDatabase();
}
return database;
}

Local database version will always be 0 and onUpgrade will not be called, because you never called getWritableDatabase/getReadableDatabase, which will bump version and return local db.
So you need:
make call getReadableDatabase(); in your contructor/oncreate, just to trigger process, in case db version is changed
or
manually check sdcard version, db.getVersion(); compare to current version - DATABASE_VERSION. And do what ever you need to do - upgrade or downgrade.