Hello - our dev team is looking into utilizing an SQLite DB as a means
to store data within our application. We've been following the
official dev guide's NotePad tutorial (http://d.android.com/guide/
tutorials/notepad/notepad-ex1.html) to accomplish this, but we're
stuck on Step 2: the preliminary creation of the database itself. We
aren't even concerned with inserting into and retrieving from the DB
yet.
Basically, we re-purposed the NoteDbAdapter.java file (renamed to
simply DbAdapter.java) to work with our main activity, called
LifeVault. When an instance of the DbAdapter class created within
LifeVault.java calls the "open()" function within DbAdapter.java,
however, the Android emulator just crashes and displays a message
along the lines of "the process has stopped working and needs to
close."
The code doesn't have any compilation errors, and it's based on the
code from the official dev guide, so we're pretty perplexed as to why
this happens.
/******************
DbAdapter.java
*******************/
package com.android.lifevault;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DbAdapter {
private static final String TAG = "DbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
private static final String DATABASE_NAME = "FVDB";
private static final String DATABASE_TABLE_USER = "User";
private static final String DATABASE_TABLE_ACH = "Ach";
private static final String DATABASE_TABLE_USER_ACH = "User_Ach";
private static final int DATABASE_VERSION = 1;
private final Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// Our "db.execSQL" statements for creating the three tables
live here
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int
newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion
+ " to "
+ newVersion + ", which will destroy all old
data");
db.execSQL("DROP TABLE IF EXISTS User_Ach");
db.execSQL("DROP TABLE IF EXISTS Ach");
db.execSQL("DROP TABLE IF EXISTS User");
onCreate(db);
}
}
/**
* Constructor - takes the context to allow the database to be
* opened/created
*/
public DbAdapter(Context ctx) {
this.mCtx = ctx;
}
/**
** Open the database - Here's where things get screwy.
**/
public DbAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
mDbHelper.close();
}
}
/******************
END DbAdapter.java
******************/
/******************
LifeVault.java
******************/
package com.android.lifevault;
import com.android.lifevault.DbAdapter;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
public class LifeVault extends Activity {
private DbAdapter mDbHelper;
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
mDbHelper = new DbAdapter(this);
mDbHelper.open(); // <--------- Program crashes here
setContentView(R.layout.main);
/**The rest of the code**/
}
}
/********************
END LifeVault.java
********************/
- Am I using the Context class incorrectly?
- Am I missing a library that the app needs to recognize the
getWritableDatabase() funciton?
Those are my two best guesses. I'm so close I can taste it!
Hopefully someone can help me see this answer that's probably right in
front of my face. Thank you; the help is greatly appreciated.
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