de.theappguys.winzigsql
Class WinzigDbFileHelper

java.lang.Object
  android.database.sqlite.SQLiteOpenHelper
      de.theappguys.winzigsql.WinzigDbFileHelper

public class WinzigDbFileHelper
extends android.database.sqlite.SQLiteOpenHelper

Extension of SQLiteOpenHelper that handles initialization of a database by using a database from a file in the assets. Automatically initializes the database from a db file in the assets. The file must be named like your database, so if your db is named "foo", it looks for the file "assets/foo.db" This helper has only very simple upgrade conventions, it simply completely replaces the current db with the one from the assets. If you need to preserve data that might have been added to the db, make sure you overwrite onCreate and handle that case manually. Works hand-in-hand with the WinzigDbProvider

Field Summary

static String

LOG_TAG

Constructor Summary

WinzigDbFileHelper(android.content.Context context, String dbName, int dbVersion)
Let your custom db provider extends this class and call the superconstructor like so:

Method Summary

protected void	copyDb() copies the database from the assets to the db file location
protected boolean	dbExists()
boolean	dropDb()
android.database.sqlite.SQLiteDatabase	getReadableDatabase()
android.database.sqlite.SQLiteDatabase	getWritableDatabase()
void	onCreate(android.database.sqlite.SQLiteDatabase db) (non-Javadoc)
void	onUpgrade(android.database.sqlite.SQLiteDatabase db, int oldVersion, int newVersion) Just overwrites the existing database with the newest one from the assets.

Methods inherited from class android.database.sqlite.SQLiteOpenHelper

close, onOpen

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG_TAG

public static final String LOG_TAG

See Also:

Constant Field Values

Constructor Detail

WinzigDbFileHelper

public WinzigDbFileHelper(android.content.Context context,
                          String dbName,
                          int dbVersion)

Let your custom db provider extends this class and call the superconstructor like so:

 private MyDbHelper(final Context context) {
     super (context, "myDbName", 42);
 }
 

Then, to obtain instances, implement a get Instance method like this:

 private static MyDbHelper instance = null;

 public static MyDbHelper(final Context context) {
     if (instance == null) {
         return (instance = new MyDbHelper(context))
     } else {
         return instance;
     }
 }
 

Method Detail

getReadableDatabase

public android.database.sqlite.SQLiteDatabase getReadableDatabase()

Overrides:

getReadableDatabase in class android.database.sqlite.SQLiteOpenHelper

getWritableDatabase

public android.database.sqlite.SQLiteDatabase getWritableDatabase()

Overrides:

getWritableDatabase in class android.database.sqlite.SQLiteOpenHelper

onCreate

public void onCreate(android.database.sqlite.SQLiteDatabase db)

(non-Javadoc)

Specified by:

onCreate in class android.database.sqlite.SQLiteOpenHelper

See Also:

SQLiteOpenHelper.onCreate(android.database.sqlite.SQLiteDatabase)

onUpgrade

public void onUpgrade(android.database.sqlite.SQLiteDatabase db,
                      int oldVersion,
                      int newVersion)

Just overwrites the existing database with the newest one from the assets. If you store custom data in your database after copying it from the assets, you need to overwrite this method and make sure the old data is preserved.

Specified by:

onUpgrade in class android.database.sqlite.SQLiteOpenHelper

See Also:

SQLiteOpenHelper.onUpgrade(android.database.sqlite.SQLiteDatabase, int, int)

copyDb

protected void copyDb()

copies the database from the assets to the db file location

Throws:

IOException

dbExists

protected boolean dbExists()

Returns:

if the database was already copied or not

dropDb

public boolean dropDb()

Returns:

true: db was deleted.