DatabaseDemo - Example

1. Create a project : DatabaseDemo
2. Do some changes in activity_main.xml
3. Create EditText and Button
<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="com.example.databasedemo.MainActivity" >

    <EditText
        android:id="@+id/name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="16dp"
        android:ems="10"
        android:hint="Enter Name" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/load"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_marginBottom="126dp"
        android:layout_marginRight="34dp"
        android:text="Load Data" />

    <Button
        android:id="@+id/save"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/load"
        android:layout_alignBottom="@+id/load"
        android:layout_alignLeft="@+id/email"
        android:text="Save Data" />

    <EditText
        android:id="@+id/email"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/load"
        android:layout_below="@+id/name"
        android:layout_marginTop="44dp"
        android:ems="10"
        android:hint="Enter email id" />

</RelativeLayout>

4. Add these EditText and Button description in MainActivity.java class
package com.example.databasedemo;

import android.database.Cursor;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {
   
    EditText name, email;
    Button save, load;
    DataHandler handler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
        name = (EditText) findViewById(R.id.name);
        email = (EditText) findViewById(R.id.email);
        save = (Button) findViewById(R.id.save);
        load = (Button) findViewById(R.id.load);
       
        save.setOnClickListener(new OnClickListener() {
           
            @Override
            public void onClick(View v) {
                String getName = name.getText().toString();
                String getEmail = email.getText().toString();
               
                handler = new DataHandler(getBaseContext());
                handler.open();
                long id = handler.insertData(getName, getEmail);
                Toast.makeText(getBaseContext(), "Data inserted", Toast.LENGTH_LONG).show();
                handler.close();
            }
        });
       
        load.setOnClickListener(new OnClickListener() {
           
            @Override
            public void onClick(View v) {
                String getName, getEmail;
                getName = "";
                getEmail = "";
               
                handler = new DataHandler(getBaseContext());
                handler.open();
                Cursor C = handler.returnData();
                if(C.moveToFirst()){
                    do{
                        getName = C.getString(0);
                        getEmail = C.getString(1);
                   
                    } while(C.moveToNext());
                }
                handler.close();
                Toast.makeText(getBaseContext(), "Name: " + getName + " and Email: " + getEmail, Toast.LENGTH_LONG).show();
            }
        });
    }

    @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;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

5. Create another java class DataHandler.java as required to handle the data
package com.example.databasedemo;

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

public class DataHandler {
    public static final String NAME = "name";
    public static final String EMAIL = "email";
    public static final String TABLE_NAME = "mytable";
    public static final String DATA_BASE_NAME = "mydatabase";
    public static final int DATABASE_VERSION = 1;
    public static final String CREATE_TABLE = "create table mytable (name text not null, email text not null)";
   
    DataBaseHelper dbhelper;
    Context context;
    SQLiteDatabase db;
   
    public DataHandler (Context context){
        this.context = context;
        dbhelper = new DataBaseHelper(context);
    }
    private static class DataBaseHelper extends SQLiteOpenHelper{

        public DataBaseHelper(Context context) {
            super(context, DATA_BASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            try {
                db.execSQL(CREATE_TABLE);
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
       
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("DROP TABLE IF EXISTS mytable");
            onCreate(db);
           
        }
       
    }
   
    public DataHandler open(){
        db = dbhelper.getWritableDatabase();
        return this;
    }
    public void close(){
        dbhelper.close();
    }
   
    public long insertData(String name, String email){
        ContentValues content = new ContentValues();
        content.put(NAME, name);
        content.put(EMAIL, email);
        return db.insertOrThrow(TABLE_NAME, null, content);
    }
   
    public Cursor returnData(){
        return db.query(TABLE_NAME, new String[] {NAME, EMAIL}, null, null, null, null, null);
    }
   
}