Content provider in android

import android.content.ContentProvider;
import android.content.ContentUris;
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;
import android.net.Uri;
import android.util.Log;

public class MyContentPro extends ContentProvider {


SQLiteDatabase db;
DbHelper helper;
static String mystring="content://com.la.andr.CustomContentProvider/stud";
static Uri Content_URI=Uri.parse(mystring);
public int delete(Uri uri, String selection, String[] selectionArgs) {
// TODO Auto-generated method stub
int n=db.delete("stud", selection,selectionArgs);
return n;
}

@Override
public String getType(Uri uri) {
// TODO Auto-generated method stub
return null;
}

@Override
public Uri insert(Uri uri, ContentValues values) {
// TODO Auto-generated method stub
long id=db.insert("stud",null, values);
Uri newUri=ContentUris.withAppendedId(uri, id);
return newUri;
}

@Override
public boolean onCreate() {
// TODO Auto-generated method stub
helper=new DbHelper(getContext(),"MyDb2",null,1);
db=helper.getWritableDatabase();
return true;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
// TODO Auto-generated method stub
Cursor c=db.query("stud", null,null,null,null,null,null);
return c;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
// TODO Auto-generated method stub

return 0;
}
public class DbHelper extends SQLiteOpenHelper
{

public DbHelper(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
// TODO Auto-generated constructor stub
}

@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("create table stud(id integer primary key autoincrement,name text not null);");
Log.d("DBHELPER","DB CREATED");

}

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

}

}

}

import android.app.Activity;

import android.content.ContentValues;

import android.database.Cursor;

import android.net.Uri;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

public class ContentEx extends Activity {

    /** Called when the activity is first created. */

   

Button view,insert,delete;

TextView tv1;

Uri u=MyContentPro.Content_URI;

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        view=(Button)findViewById(R.id.button1);

        insert=(Button)findViewById(R.id.button2);

        delete=(Button)findViewById(R.id.button3);

        tv1=(TextView)findViewById(R.id.tv);

        view.setOnClickListener(new OnClickListener()

        {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

Cursor c=managedQuery(u,null,null,null,null);

String res="";

if(c.moveToFirst())

{

do

{

res+=c.getString(c.getColumnIndex("id"))

+c.getString(c.getColumnIndex("name"));

}while(c.moveToNext());

tv1.setText(res);

}

}

       

        });

        insert.setOnClickListener(new OnClickListener()

        {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

ContentValues cv=new ContentValues();

cv.put("name","dheeraj");

getContentResolver().insert(u, cv);

tv1.setText("inserted");

}

       

        });

        delete.setOnClickListener(new OnClickListener()

        {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

int i=getContentResolver().delete(u, "name='dheeraj'", null);

tv1.setText("deleted row"+i);

}

       

        });

    }

}