[Java for Android App Development] Traabefi:
Hello everybody. I've tried to make a suitable database for my game that will represent shop stock. The problem is when I call the purchase() method, I got that exception mentioned in the title. The problem is that I need to chceck depending on ID if I need to increment number of purchases or i just unlock the whole item. Here is my code for the database

public class MonsterTapDatabase extends SQLiteOpenHelper {
static final String dbName = "MonsterTapDb";
static final int version = 1;
static final String tTableName = "Shop";
static final String fItemID = "ItemID";
static final String fItemName = "ItemName";
static final String fItemNumberOfPurchases = "NumberOfPurchases";
static final String fItemIsLocked = "IsItemLocked";

public MonsterTapDatabase(Context context) {
super(context, dbName, null, version);
}

@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("CREATE TABLE IF NOT EXISTS "+tTableName+" (" +
fItemID + " INTEGER PRIMARY KEY , " +
fItemName + " TEXT , " +
fItemNumberOfPurchases + " INT, " +
fItemIsLocked + " TEXT" +
")");
ContentValues cv = new ContentValues();
cv.put(fItemID, 1);
cv.put(fItemName, "Lives");
cv.put(fItemNumberOfPurchases, 0);
cv.put(fItemIsLocked, "true");
sqLiteDatabase.insert(tTableName, null, cv);
cv.put(fItemID, 2);
cv.put(fItemName, "Hardmode");
cv.put(fItemNumberOfPurchases, 0);
cv.put(fItemIsLocked, "true");
sqLiteDatabase.insert(tTableName, null, cv);
cv.put(fItemID, 3);
cv.put(fItemName, "Reversed");
cv.put(fItemNumberOfPurchases, 0);
cv.put(fItemIsLocked, "true");
sqLiteDatabase.insert(tTableName, null, cv);
cv.put(fItemID, 4);
cv.put(fItemName, "Reversed Hardmode");
cv.put(fItemNumberOfPurchases, 0);
cv.put(fItemIsLocked, "true");
sqLiteDatabase.insert(tTableName, null, cv);
}

@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + tTableName);
onCreate(sqLiteDatabase);
}
public void purchase(int ID){
if(ID==1){
SQLiteDatabase myDB = this.getReadableDatabase();
String[] mySearch = new String[]{String.valueOf(ID)};
Cursor myCursor = myDB.rawQuery("SELECT "+ fItemNumberOfPurchases +" FROM "+ tTableName +" WHERE "+ fItemID +"=?",mySearch);
myCursor.moveToFirst();
int index = myCursor.getColumnIndex(fItemNumberOfPurchases);
if(index<5){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(fItemNumberOfPurchases, index);
db.update(tTableName,cv, fItemID, new String[]{String.valueOf(ID)});
}
else{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(fItemIsLocked, false);
db.update(tTableName,cv, fItemID, new String[]{String.valueOf(ID)});
}
myCursor.close();
}
else{
SQLiteDatabase myDB = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(fItemIsLocked, false);
cv.put(fItemNumberOfPurchases, 1);
myDB.update(tTableName, cv, fItemID+"=?", new String []{String.valueOf(ID)});
}
}
public String isPurchased(int ID){
SQLiteDatabase myDB = this.getReadableDatabase();
String[] mySearch = new String[]{String.valueOf(ID)};
Cursor myCursor = myDB.rawQuery("SELECT "+ fItemIsLocked +" FROM "+ tTableName +" WHERE "+ fItemID +"=?",mySearch);
myCursor.moveToFirst();
int index = myCursor.getColumnIndex(fItemID);
String myAnswer = myCursor.getString(index);
myCursor.close();
return myAnswer;
}
public int numberOfLives(){
int ID = 1;
SQLiteDatabase myDB = this.getReadableDatabase();
String[] mySearch = new String[]{String.valueOf(ID)};
Cursor myCursor = myDB.rawQuery("SELECT "+ fItemNumberOfPurchases +" FROM "+ tTableName +" WHERE "+ fItemID +"=?",mySearch);
myCursor.moveToFirst();
int index = myCursor.getColumnIndex(fItemNumberOfPurchases);
myCursor.close();
return index;
}
}