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mikeplate/SimpleDatabaseHelper.java

Created February 23, 2014 15:46
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  1. mikeplate created this gist Feb 23, 2014.
    127 changes: 127 additions & 0 deletions SimpleDatabaseHelper.java
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    package se.mobileapplab.datademo;

    import android.content.ContentValues;
    import android.content.Context;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;

    /**
    * Class that wraps the most common database operations. This example assumes you want a single table and data entity
    * with two properties: a title and a priority as an integer. Modify in all relevant locations if you need other/more
    * properties for your data and/or additional tables.
    */
    public class SimpleDatabaseHelper {
    private SQLiteOpenHelper _openHelper;

    /**
    * Construct a new database helper object
    * @param context The current context for the application or activity
    */
    public SimpleDatabaseHelper(Context context) {
    _openHelper = new SimpleSQLiteOpenHelper(context);
    }

    /**
    * This is an internal class that handles the creation of all database tables
    */
    class SimpleSQLiteOpenHelper extends SQLiteOpenHelper {
    SimpleSQLiteOpenHelper(Context context) {
    super(context, "main.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
    db.execSQL("create table todos (_id integer primary key autoincrement, title text, priority integer)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    }
    }

    /**
    * Return a cursor object with all rows in the table.
    * @return A cursor suitable for use in a SimpleCursorAdapter
    */
    public Cursor getAll() {
    SQLiteDatabase db = _openHelper.getReadableDatabase();
    if (db == null) {
    return null;
    }
    return db.rawQuery("select * from todos order by priority, title", null);
    }

    /**
    * Return values for a single row with the specified id
    * @param id The unique id for the row o fetch
    * @return All column values are stored as properties in the ContentValues object
    */
    public ContentValues get(long id) {
    SQLiteDatabase db = _openHelper.getReadableDatabase();
    if (db == null) {
    return null;
    }
    ContentValues row = new ContentValues();
    Cursor cur = db.rawQuery("select title, priority from todos where _id = ?", new String[] { String.valueOf(id) });
    if (cur.moveToNext()) {
    row.put("title", cur.getString(0));
    row.put("priority", cur.getInt(1));
    }
    cur.close();
    db.close();
    return row;
    }

    /**
    * Add a new row to the database table
    * @param title The title value for the new row
    * @param priority The priority value for the new row
    * @return The unique id of the newly added row
    */
    public long add(String title, int priority) {
    SQLiteDatabase db = _openHelper.getWritableDatabase();
    if (db == null) {
    return 0;
    }
    ContentValues row = new ContentValues();
    row.put("title", title);
    row.put("priority", priority);
    long id = db.insert("todos", null, row);
    db.close();
    return id;
    }

    /**
    * Delete the specified row from the database table. For simplicity reasons, nothing happens if
    * this operation fails.
    * @param id The unique id for the row to delete
    */
    public void delete(long id) {
    SQLiteDatabase db = _openHelper.getWritableDatabase();
    if (db == null) {
    return;
    }
    db.delete("todos", "_id = ?", new String[] { String.valueOf(id) });
    db.close();
    }

    /**
    * Updates a row in the database table with new column values, without changing the unique id of the row.
    * For simplicity reasons, nothing happens if this operation fails.
    * @param id The unique id of the row to update
    * @param title The new title value
    * @param priority The new priority value
    */
    public void update(long id, String title, int priority) {
    SQLiteDatabase db = _openHelper.getWritableDatabase();
    if (db == null) {
    return;
    }
    ContentValues row = new ContentValues();
    row.put("title", title);
    row.put("priority", priority);
    db.update("todos", row, "_id = ?", new String[] { String.valueOf(id) } );
    db.close();
    }
    }