insert data in sqllite database through android

package com.example.sqllite;



import android.os.Bundle;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
SQLiteDatabase db;
EditText name;
EditText mail;
EditText address;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db=openOrCreateDatabase("Mydb",MODE_PRIVATE, null);
db.execSQL("create table if not exists student(name varchar,mail varchar,address varchar);");

name=(EditText)findViewById(R.id.editText1);
mail=(EditText)findViewById(R.id.editText2);
address=(EditText)findViewById(R.id.editText2);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void adddata(View v)
{
String n=name.getText().toString();
String m=mail.getText().toString();
String a=address.getText().toString();
db.execSQL("insert into student(name,mail,address) values('"+n+"','"+m+"','"+a+"');");
Toast.makeText(getApplicationContext(),"Saved Successfully",Toast.LENGTH_LONG).show();
}
public void show(View v)
{
Cursor c=db.rawQuery("select * from student", null);
int count =c.getCount();
c.moveToFirst();
TableLayout tb=new TableLayout(getApplicationContext());
tb.setVerticalScrollBarEnabled(true);
TableRow tableRow=new TableRow(getApplicationContext());
TextView tv,tv1,tv2,tv3,tv4,tv5;
tv=new TextView(getApplicationContext());
tv.setText("name");
tv.setPadding(20, 10, 10, 20);
tableRow.addView(tv);
tv1=new TextView(getApplicationContext());
tv1.setText("mail");
tv1.setPadding(20, 10, 10, 20);
tableRow.addView(tv1);
tv2=new TextView(getApplicationContext());
tv2.setText("address");
tv2.setPadding(20, 10, 10, 20);
tableRow.addView(tv2);

tb.addView(tableRow);
for(int j=0;j<count;j++)
{
tableRow=new TableRow(getApplicationContext());
tv3=new TextView(getApplicationContext());
tv3.setText(c.getString(c.getColumnIndex("name")));
tv4=new TextView(getApplicationContext());
tv4.setText(c.getString(c.getColumnIndex("mail")));
tv5=new TextView(getApplicationContext());
tv5.setText(c.getString(c.getColumnIndex("address")));
tv3.setPadding(20, 10, 10, 20);
tv4.setPadding(20, 10, 10, 20);
tv5.setPadding(20, 10, 10, 20);
tableRow.addView(tv3);
tableRow.addView(tv4);
tableRow.addView(tv5);
tb.addView(tableRow);
c.moveToNext();
}
setContentView(tb);
db.close();
}
}

res/layout/activity_main.xml

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

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

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_alignParentTop="true"

        android:layout_marginLeft="14dp"

        android:layout_marginTop="24dp"

        android:text="Name" />

    <TextView

        android:id="@+id/textView2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/textView1"

        android:layout_below="@+id/textView1"

        android:layout_marginTop="26dp"

        android:text="Mail" />

    <TextView

        android:id="@+id/textView3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/textView2"

        android:layout_below="@+id/textView2"

        android:layout_marginTop="24dp"

        android:text="Address" />

    <EditText

        android:id="@+id/editText1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/textView1"

        android:layout_alignBottom="@+id/textView1"

        android:layout_alignParentRight="true"

        android:ems="10" />

    <EditText

        android:id="@+id/editText2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/editText1"

        android:layout_alignTop="@+id/textView2"

        android:ems="10" >

        <requestFocus />

    </EditText>

    <EditText

        android:id="@+id/editText3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/editText2"

        android:layout_alignTop="@+id/textView3"

        android:ems="10" />

    <Button

        android:id="@+id/button1"

        style="@style/AppBaseTheme"

        android:layout_width="wrap_content"

        android:layout_height="40dp"

        android:layout_alignLeft="@+id/editText3"

        android:layout_centerVertical="true"

        android:onClick="adddata"

        android:text="Save" />

    <Button

        android:id="@+id/button2"

        android:layout_width="wrap_content"

        android:layout_height="40dp"

        android:layout_alignBaseline="@+id/button1"

        android:layout_alignBottom="@+id/button1"

        android:layout_alignRight="@+id/editText3"

        android:layout_marginRight="32dp"

        android:onClick="show"

        android:text="Show" />

</RelativeLayout>