I am passing VariableA (barTableName ) to an SQLite query, "SELECT * FROM " + barTableName + " WHERE DRINKTYPE='Beer';". I need barTableName to be able to change, based on what a user chooses. When I hardcode the variable, it works. If I try to change it at all, no matter how far back in the "variable timeline", it gives me a null point exception. Does anyone know how I could acomplish this?
DBHelper
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper {
private static String DB_PATH = "/data/data/com.example.sixth/databases/";
private static String DB_NAME = "BarSample.db";
private final Context myContext;
public static String tableName = "BARS";
String barTableName, sqlquery ;
public static String firstBarTableName = MainActivity.upperCaseName;//Pass in the specific bar from the spinner choice
private SQLiteDatabase myDataBase;
public DBHelper(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 {
this.close();
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) {
}
public List<String> getAllLabels(){
List<String> labels = new ArrayList<String>();
// Select All Query
String selectQuery = "SELECT * FROM " + tableName;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
labels.add(cursor.getString(1) + " " + cursor.getString(2)+ ", " + cursor.getString(3));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning labels
return labels;
} // will returns all labels stored in database
public List<String> getBeerDrinkLabels(){
//naming();
List<String> allBeerDrinkLabels = new ArrayList<String>();
if (firstBarTableName.equals("CHANGOS")){
sqlquery = "SELECT * FROM CHANGOS WHERE DRINKTYPE='Beer';";
}
else if(firstBarTableName.equals("LANDOS")){
sqlquery = "SELECT * FROM LANDOS WHERE DRINKTYPE='Beer';";
}
else{
sqlquery = "SELECT * FROM ANTHONYS WHERE DRINKTYPE='Beer';";
}
//String sqlquery="SELECT * FROM " + barTableName + " WHERE DRINKTYPE='Beer';";
String selectQuery = sqlquery;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
allBeerDrinkLabels.add(cursor.getString(1) + " Price: " + cursor.getString(2));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning labels
return allBeerDrinkLabels;
} // will returns all labels stored in database
public List<String> getWineDrinkLabels(){
List<String> allWineDrinkLabels = new ArrayList<String>();
// Select All Query
String sqlquery="SELECT * FROM "+barTableName + " WHERE DRINKTYPE='Wine';";
String selectQuery = sqlquery;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
allWineDrinkLabels.add(cursor.getString(1) + ", " + cursor.getString(2));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning labels
return allWineDrinkLabels;
} // will returns all labels stored in database
public List<String> getMixedDrinkDrinkLabels(){
List<String> allMixedDrinkDrinkLabels = new ArrayList<String>();
// Select All Query
String sqlquery="SELECT * FROM "+barTableName + " WHERE DRINKTYPE='Mixed Drink';";
String selectQuery = sqlquery;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
allMixedDrinkDrinkLabels.add(cursor.getString(1) + ", " + cursor.getString(2));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning labels
return allMixedDrinkDrinkLabels;
} // will returns all labels stored in database
public List<String> getOtherDrinkLabels(){
List<String> allOtherDrinkLabels = new ArrayList<String>();
// Select All Query
String sqlquery="SELECT * FROM "+barTableName + " WHERE DRINKTYPE='Other';";
String selectQuery = sqlquery;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
allOtherDrinkLabels.add(cursor.getString(1) + ", " + cursor.getString(2));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning labels
return allOtherDrinkLabels;
} // will returns all labels stored in database
public List<String> getShotsDrinkLabels(){
List<String> allShotsDrinkLabels = new ArrayList<String>();
// Select All Query
String sqlquery="SELECT * FROM "+barTableName + " WHERE DRINKTYPE='Shots';";
String selectQuery = sqlquery;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
allShotsDrinkLabels.add(cursor.getString(1) + ", " + cursor.getString(2));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning labels
return allShotsDrinkLabels;
} // will returns all labels stored in database
}
I'm currently try to assign it to splquery with an If statement, based on what is coming in from the other class. I have double, triple checked. The variable coming in IS one of the 3 that are in the if statement, all in caps like is in the statement. I've been working on this for a long while and am beating my head against the wall. Any help would be VERY appreciated.
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