It's been a while since I was here. Anyway, I recently made an update to the iOS version of my app, which now allows users to save and load data via SQLite. However, I do not want to leave Android users out in the cold, so I decided to try and bring an SQLite back-end to the Android version too. However, I am having some issues. When I launch my app in the emulator, my app crashes. Upon inspection via adb shell, I noticed that the table is not being created, since no tables are listed in the database. How do I fix this?
Here is the code for my handler class:
I am still very new to using database back-ends outside of PHP+MySQL, even though iOS was my first experience with SQLite, which was using the FMDB wrapper.
Update: Never mind, it looks like it was created, after I decided to put in the semi-colon, as if I were using SQLite via command line.
Here is the code for my handler class:
Code:
import java.util.*;
import android.content.*;
import android.database.*;
import android.database.sqlite.*;
import android.database.sqlite.*;
public class DBHandler extends SQLiteOpenHelper
{
// static variables
private static final int DATABASE_VERSION = 1; // version
private static final String DATABASE_NAME = "mrd.db"; /* database name */
private static final String TABLE_NAME = "rmd"; // db name
// field names
private static final String key = "id";
private static final String bd = "birth";
private static final String ira = "bal";
private static final String distrib = "year";
// variables to hold data
String birth;
double bal;
int year, records;
public DBHandler(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// method to create table
@Override
public void onCreate(SQLiteDatabase db)
{
String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME + "(" + key + " INTEGER PRIMARY KEY AUTOINCREMENT, " + bd + " TEXT, " + ira + " REAL, " + distrib + " INTEGER)";
db.execSQL(CREATE_TABLE);
}
// method to upgrade database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
// drop table if exists
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
// recreate table
onCreate(db);
}
// create insert method
public void saveData(String a, double b, int c)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(bd, a);
values.put(ira, b);
values.put(distrib, c);
// insert statement
db.insert(TABLE_NAME, null, values);
db.close();
}
// create update method
public int updateData(String a, double b, int c)
{
int test;
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
if (getBirth().equals(a) != true && getBal() != b && getYear() != c)
{
values.put(bd, a);
values.put(ira, b);
values.put(distrib, c);
if (db.update(TABLE_NAME, values, key + " = ?", new String[] { Integer.toString(1)}) != 0)
{
test = 1;
}
else
{
test = 0;
}
}
else if (getBirth().equals(a) != true && getBal() != b)
{
values.put(bd, a);
values.put(ira, b);
if (db.update(TABLE_NAME, values, key + " = ?", new String[] { Integer.toString(1)}) != 0)
{
test = 1;
}
else
{
test = 0;
}
}
else if (getBirth().equals(a) != true && getYear() != c)
{
values.put(bd, a);
values.put(distrib, c);
if (db.update(TABLE_NAME, values, key + " = ?", new String[] { Integer.toString(1)}) != 0)
{
test = 1;
}
else
{
test = 0;
}
}
else if (getBal() != b && getYear() != c)
{
values.put(ira, b);
values.put(distrib, c);
if (db.update(TABLE_NAME, values, key + " = ?", new String[] { Integer.toString(1)}) != 0)
{
test = 1;
}
else
{
test = 0;
}
}
else if (getYear() != c)
{
values.put(distrib, c);
if (db.update(TABLE_NAME, values, key + " = ?", new String[] { Integer.toString(1)}) != 0)
{
test = 1;
}
else
{
test = 0;
}
}
else if (getBal() != b)
{
values.put(ira, b);
if (db.update(TABLE_NAME, values, key + " = ?", new String[] { Integer.toString(1)}) != 0)
{
test = 1;
}
else
{
test = 0;
}
}
else if (getBirth().equals(a) != true)
{
values.put(bd, a);
if (db.update(TABLE_NAME, values, key + " = ?", new String[] { Integer.toString(1)}) != 0)
{
test = 1;
}
else
{
test = 0;
}
}
else
{
test = 0;
}
return test;
}
// the following methods retrieve data
public String getBirth()
{
String birthQuery = "SELECT date(" + bd + ") FROM rmd LIMIT 1";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(birthQuery, null);
if (cursor != null)
cursor.moveToFirst();
birth = cursor.getString(0);
return birth;
}
public double getBal() throws SQLException
{
String balQuery = "SELECT " + ira + " FROM rmd LIMIT 1";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(balQuery, null);
if (cursor != null)
cursor.moveToFirst();
bal = cursor.getDouble(0);
return bal;
}
public int getYear() throws SQLException
{
String distQuery = "SELECT " + distrib + " FROM rmd LIMIT 1";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(distQuery, null);
if (cursor != null)
cursor.moveToFirst();
year = cursor.getInt(0);
return year;
}
// the following method gets number of records
public int records() throws SQLException
{
String rowCount = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(rowCount, null);
cursor.close();
return records = cursor.getCount();
}
}I am still very new to using database back-ends outside of PHP+MySQL, even though iOS was my first experience with SQLite, which was using the FMDB wrapper.
Update: Never mind, it looks like it was created, after I decided to put in the semi-colon, as if I were using SQLite via command line.