Hie,This Is Naresh...[Senior Member of Xda-Developers]..

Tutorial of How to Create and Access Database in single java file in Android?

MainActivity code:

public class MainActivity extends Activity{
   //creating access variable for DataBase
  SQLiteDatabase db;

  @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
          Button b=(Button) findViewById(R.id.delapp);
         //To open or create a database
                final SQLiteDatabase db =openOrCreateDatabase("Example",MODE_WORLD_WRITEABLE, null);
        //for creating table in database
                    db.execSQL("CREATE TABLE IF NOT EXISTS EXAMPLE(NAME VARCHAR);");
       
//inserting values into table
                 for(int i=0;i<10;i++)
                 {
                db.execSQL("INSERT INTO EXAMPLE VALUES('"+i+"')");

}      
                  b.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
//cursor is used for accessing data from database table..
//SELECT NAME[you can add columns hereseparating them with comma] FROM EXAMPLE..
Cursor c1=db.rawQuery("SELECT NAME FROM EXAMPLE", null);
                             //moveToFirst() is used to point to starting row of the database table
      if (c1.moveToFirst())
      {
          do
          {
                                 //c1.getString(0) will provide the column NAME value..here '0' is column index..if you have //any other column //in database after NAME then the index number will be "1" and so on..
                                  String v = c1.getString(0);
    //Toasting the values inserted into table..   
                                  Toast.makeText(app.getApplicationContext(),v,100).show();
          }
          while (c1.moveToNext());
//c1.moveToNext() will make cursor to move to next position..
      }
      if (c1 != null && !c1.isClosed())
      {
//c1.close(); is closing of cursor.[it is not mandatory in some cases..but better practice with closing cursor]..
          c1.close();
      }
   
});
 
 }
}

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/fullView"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    >

  

        <Button

            android:id="@+id/delapp"

            android:layout_width="45dp"

            android:layout_height="match_parent"

            android:layout_above="@+id/button3"

            android:layout_centerHorizontal="true"

            android:layout_marginLeft="61dp"

            android:text="Button" />

</RelativeLayout>

CHECK My Android APPS:
NCDupRemover-Backup,Clear all Contacts and Remove Duplicate Contacts..
NLauncherV2.2.2-Multipurpose Launcher
NLauncherCV0.2
NMemoV0.2

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