Wednesday, June 1, 2011

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.

A simple example using Android's SQLite database

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>


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Related Post:
- A simple example using Android's SQLite database, exposes data from Cursor to a ListView.




12 comments:

Memtech said...

this is awesome post, another helpful post you may check the following link...
http://mindstick.com/Articles/af5c031a-e435-4642-8464-9f7d375087c2/?SQLite%20in%20Android

Thanks!!

Ashwin Raj said...

The best solution found after trying all the blogs, websites, forums.
I was able to accomplish my task after so many days of effort. This is the right place to be.

Programing Solution said...

thanks

attilahooper said...

THANKYOU ! Dead simple for a newb like me. Helped debug config problems with, and tested on, Android 2.2 platform, Win64/Eclipse64/JDK64. success.

Android Apps said...

I can;t get this code to work- looks like something broke in the new android classes

stephy yan said...

Hihi ^^ Is there any recommended tutorial on how to create multiple tables in android? Including adding some value into each table. As I found all tutorial only create 1 table.

I am new in Android and Java so I have no idea on how to do it.

Anonymous said...

finally a working example....
Thanks

Anonymous said...

Dude you are a genius. Excellent example!

Smit Joshi said...

Thank you so Much ! You saved me !

Anonymous said...

Not getting the contentlist appear, only the 'Hello' text. Any ideas? No errors are appearing.

Eamon said...

Only getting the hello text appear and not the content list. All seems to be fine in the build. Any ideas?

smit joshi said...

thankssssssssssssssssssss