A simple example using Android's SQLite database

A simple example using Android's SQLite database

It's a simple example using Android's SQLite database. A adapter, SQLiteAdapter, is implement as a adapter between our activity and SQLite, with a inner class SQLiteHelper which extends SQLiteOpenHelper.

The SQLite database have only one field, "Content". When the app start, it will open the database and delete all first, then insert some dummy data, then close it. And Re-open, read all content.



AndroidSQLite.java

package com.exercise.AndroidSQLite;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class AndroidSQLite extends Activity {
 
 private SQLiteAdapter mySQLiteAdapter;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        TextView listContent = (TextView)findViewById(R.id.contentlist);
        
        /*
         *  Create/Open a SQLite database
         *  and fill with dummy content
         *  and close it
         */
        mySQLiteAdapter = new SQLiteAdapter(this);
        mySQLiteAdapter.openToWrite();
        mySQLiteAdapter.deleteAll();
        mySQLiteAdapter.insert("ABCDE");
        mySQLiteAdapter.insert("FGHIJK");
        mySQLiteAdapter.insert("1234567");
        mySQLiteAdapter.insert("890");
        mySQLiteAdapter.insert("Testing");
        mySQLiteAdapter.close();

        /*
         *  Open the same SQLite database
         *  and read all it's content.
         */
        mySQLiteAdapter = new SQLiteAdapter(this);
        mySQLiteAdapter.openToRead();
        String contentRead = mySQLiteAdapter.queueAll();
        mySQLiteAdapter.close();
        
        listContent.setText(contentRead);
        
    }
}

SQLiteAdapter.java

package com.exercise.AndroidSQLite;

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

public class SQLiteAdapter {

 public static final String MYDATABASE_NAME = "MY_DATABASE";
 public static final String MYDATABASE_TABLE = "MY_TABLE";
 public static final int MYDATABASE_VERSION = 1;
 public static final String KEY_CONTENT = "Content";

 //create table MY_DATABASE (ID integer primary key, Content text not null);
 private static final String SCRIPT_CREATE_DATABASE =
  "create table " + MYDATABASE_TABLE + " ("
  + KEY_CONTENT + " text not null);";
 
 private SQLiteHelper sqLiteHelper;
 private SQLiteDatabase sqLiteDatabase;

 private Context context;
 
 public SQLiteAdapter(Context c){
  context = c;
 }
 
 public SQLiteAdapter openToRead() throws android.database.SQLException {
  sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION);
  sqLiteDatabase = sqLiteHelper.getReadableDatabase();
  return this; 
 }
 
 public SQLiteAdapter openToWrite() throws android.database.SQLException {
  sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION);
  sqLiteDatabase = sqLiteHelper.getWritableDatabase();
  return this; 
 }
 
 public void close(){
  sqLiteHelper.close();
 }
 
 public long insert(String content){
  
  ContentValues contentValues = new ContentValues();
  contentValues.put(KEY_CONTENT, content);
  return sqLiteDatabase.insert(MYDATABASE_TABLE, null, contentValues);
 }
 
 public int deleteAll(){
  return sqLiteDatabase.delete(MYDATABASE_TABLE, null, null);
 }
 
 public String queueAll(){
  String[] columns = new String[]{KEY_CONTENT};
  Cursor cursor = sqLiteDatabase.query(MYDATABASE_TABLE, columns, 
    null, null, null, null, null);
  String result = "";
  
  int index_CONTENT = cursor.getColumnIndex(KEY_CONTENT);
  for(cursor.moveToFirst(); !(cursor.isAfterLast()); cursor.moveToNext()){
   result = result + cursor.getString(index_CONTENT) + "\n";
  }
 
  return result;
 }
 
 public class SQLiteHelper extends SQLiteOpenHelper {

  public SQLiteHelper(Context context, String name,
    CursorFactory factory, int version) {
   super(context, name, factory, version);
  }

  @Override
  public void onCreate(SQLiteDatabase db) {
   // TODO Auto-generated method stub
   db.execSQL(SCRIPT_CREATE_DATABASE);
  }

  @Override
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
   // TODO Auto-generated method stub

  }

 }
 
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<TextView
 android:id="@+id/contentlist"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"/>
</LinearLayout>