android example

https://www.codeofaninja.com/2013/02/android-sqlite-tutorial.html

spinner and round corners

round_color_for_spinner.xml (drawable)
<?xml version="1.0" encoding="utf-8"?><!--  res/drawable/rounded_edittext.xml -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:padding="10dp"
    android:shape="rectangle">
    <solid android:color="@color/white" />
    <stroke
        android:width="3dip"
        android:color="@color/light_gray" />
    <corners
        android:bottomLeftRadius="15dp"
        android:bottomRightRadius="15dp"
        android:topLeftRadius="15dp"
        android:topRightRadius="15dp" />

</shape>

Spinners

public class MainActivity extends Activity
{
    private Spinner project;
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        // init view
        project=(Spinner)findViewById(R.id.SpinnerProject);
        List<String> list = new ArrayList<String>();
        list.add("Pro-XXX-XXX");
        list.add("TRN-XXX-XXX");
        list.add("SRV-XXX-XXX");

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, R.layout.spinner_item, list);
        // adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        project.setAdapter(adapter);
    }
}



use spinner in Colors
spRespons.setOnItemSelectedListener(new OnItemSelectedListener() {

            @Override
            public void onItemSelected(AdapterView<?> parent, View arg1,
                    int arg2, long arg3) {

                   ((TextView) parent.getChildAt(0)).setTextColor(Color.parseColor(getResources().getString(R.color.GRENN_COLOR)));
                   ((TextView) parent.getChildAt(0)).setTextSize(TypedValue.COMPLEX_UNIT_SP, 12F);
                   ((TextView) parent.getChildAt(0)).setTypeface(ARABIC_FONT);
            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {
                // TODO Auto-generated method stub
            }
        });



dynamically change the content of spinner


Spinner spinner = (Spinner)findViewById(R.id.mySpinner);
ArrayAdapter<String> spinnerAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, android.R.id.text1);
spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(spinnerAdapter);
spinnerAdapter.add("value");
spinnerAdapter.notifyDataSetChanged();

canvas reading

As I mentioned before, drawing on Canvas is usually done in performance intensive applications like video games.

There are 2 ways to draw things on a canvas in Android - the first one is to draw on a View, the second way is to draw on a SurfaceView.

Drawing on a View is more suitable when your application does not need to update the screen really fast. It can be used for a game of chess or a similar slow-paced application. The Android system provides a Canvas object that will display our graphics in a View.

To use this method, you need to create a custom class that extends View and has the onDraw() callback method. The onDraw() method is called by Android to tell your View to update its graphics. This is where you can put all the code that draws things using the Canvas type object that is passed as the parameter to this function. The class has a set of methods for drawing that you can use, which include drawBitmap(), drawRect(), drawText() and others.

Note, however, that Android will only call onDraw() of your View if it is necessary. If you decide your application is ready to be drawn, you need to call the View's invalidate() method. This tells Android that the contents should be redrawn. However, using this method does not guarantee that the redraw will occur instantly.

What's interesting is that other classes also have draw() method, which lets you take those Drawables and pass them onto the Canvas to be drawn there.

The other way to draw on a canvas is using the SurfaceView class.

This subclass of View lets us create a dedicated drawing surface inside a View, which is treated just like any other View in theapplication. This surface is offered a separate thread where all the drawing happens, so our main application thread does not hold it back from updating.

In this case you will also need to create a custom class. This time it extends SurfaceView. It should also implement SurfaceHolder.Callback class. This subclass is used to inform you when the underlying Surface dispatches an event, for example, when it is created or changed.

The secondary thread should be defined inside your SurfaceView class. You shouldn't handle the Surface object directly - it can be done using SurfaceHandler. When the SurfaceView object is initialized, you can access the SurfaceHolder object using getHolder() method. Then you tell SurfaceHolder that you want to receive SurfaceHolder callbacks from SurfaceHolder.Callback by calling addCallback(this).

You can then override all the SurfaceHolder.Callback methods inside your SurfaceView class. Those methods are surfaceChanged, surfaceCreated and surfaceDestroyed.

To draw to the SurfaceCanvas from withing your secondary thread, pass the SurfaceHandler object to the thread and retrieve the Canvas with lockCanvas(). You can then take and use the Canvas to draw on it. When you're done drawing, call unlockCanvasAndPost(), passing it your Canvas object. The Surface then draws the Canvas. You need to lock and unlock every time you want to update the screen.

That's all for today. We haven't written a single line of code today but hopefully you now understand the basic mechanism behind drawing graphics in Android. The code itself is pretty self explanatory and will be shown in future tutorials as practical examples.

Thanks for reading!

Transition

In this tutorial we will take a look at the TransitionDrawable class, which lets us display a smooth cross-fade effect between two pictures.

Firstly, we'll need to add 2 pictures to the drawable directory of the project. In my case, they are sample1.jpg and sample2.jpg, and I put both of them in res/drawable-hdpi/ directory.

Add an xml file in the same directory, call it transition.xml. Here we will add a transition node with 2 item nodes inside, each representing an image:
<?xml version="1.0" encoding="utf-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/d1"/>
    <item android:drawable="@drawable/d8"/>
</transition>




package com.example.trans;

import android.content.res.Resources;
import android.graphics.drawable.TransitionDrawable;
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.ImageView;


public class MainActivity extends ActionBarActivity {
private ImageView image;
private TransitionDrawable trans;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
     
        image = (ImageView)findViewById(R.id.image);
        Resources res = this.getResources();
        trans = (TransitionDrawable)res.getDrawable(R.drawable.transition);
     
        image.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
        image.setImageDrawable(trans);
        trans.reverseTransition(1000);
        }
        });
    }

}

<LinearLayout 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:orientation="vertical"

    tools:context=".MainActivity" >

    

    <ImageView

        android:id="@+id/image"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:src="@drawable/d1"

        />

    

</LinearLayout>

Intents Basic Example Between screens

MainActivity.java


package bhanu.firstapp;

import android.content.Intent;
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 {

Button b1,b2,st;
EditText et1,et2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b1=(Button)findViewById(R.id.button1);
        b2=(Button)findViewById(R.id.button2);
        st=(Button)findViewById(R.id.button3);
        et1=(EditText)findViewById(R.id.editText1);
     
        b1.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
String str1=et1.getText().toString();
Intent in=new Intent(MainActivity.this,Second.class);
in.putExtra("data", str1);
startActivity(in);
Toast.makeText(getApplicationContext(), "you Clicked on submit", 100).show();

}
});
     
        b2.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "You clicked on cancel", 1000).show();
}
});
        st.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent in1=new Intent(MainActivity.this,Two.class);
startActivity(in1);
}
});
    }

    @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);
    }
}

Second.java

package bhanu.firstapp;

import android.app.Activity;

import android.graphics.Color;

import android.os.Bundle;

import android.support.annotation.ColorRes;

import android.widget.TextView;

import android.widget.Toast;

public class Second extends Activity

{

//TextView t1;

protected void onCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       String str= getIntent().getExtras().getString("data");

       Toast.makeText(getApplicationContext(), str, 500).show();

       TextView t1=new TextView(getApplicationContext());

       t1.setTextColor(Color.YELLOW);

       t1.setText("welcome"+ " " +str);

       setContentView(t1);

       

}

}

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="bhanu.firstapp.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_marginTop="28dp"

        android:text="@string/usn" />

    <EditText

        android:id="@+id/editText2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/editText1"

        android:layout_below="@+id/editText1"

        android:layout_marginTop="19dp"

        android:ems="10"

        android:inputType="textPassword" />

    <TextView

        android:id="@+id/textView2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/editText2"

        android:layout_alignBottom="@+id/editText2"

        android:layout_alignLeft="@+id/textView1"

        android:text="@string/pwd" />

    <Button

        android:id="@+id/button2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBottom="@+id/button1"

        android:layout_alignRight="@+id/editText1"

        android:text="@string/can" />

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/textView2"

        android:layout_below="@+id/textView2"

        android:text="@string/sub" />

    <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_toRightOf="@+id/textView1"

        android:ems="10" />

    <Button

        android:id="@+id/button3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_below="@+id/button1"

        android:layout_marginTop="46dp"

        android:layout_toRightOf="@+id/textView2"

        android:text="@string/st" />

</RelativeLayout>

two.xml

<?xml version="1.0" encoding="utf-8"?>

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

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Welcome"

        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

Introduction of How Android Works for Java Programmers

Android development is current buzz in Java programming world. It's the Android, which keeps Java in the fore front from last couple of years. Now, How important is to understand or learn Android for Java programmers? Well it depends, if you like application development and want to reach mass, Android offers that opportunity to you. Millions of Android phones are available and they are keep increasing, with pace, much higher than IPhone or iOS. What all these means is, it does make a lot of sense to learn Android programming for Java programmer, and this article is about that, but this is also a one of the  good reason to learn Java programming. This tutorial will give you basic idea of How Android works? not detailed but a good overview. One distinct advantage Java programmers has over others is that Android API is much like Java API, though Android doesn't support all classes available in J2SE SDK, it supports critical ones. Another advantage is that, you can use same tools e.g. IDE like Eclipse to develop Android applications, Google provides Eclipse plug-in for Android development. On opposite, if you want to go for  iOS development, A steep learning curve with Objective C and iOS SDK waits you. I think it make more sense for a C++ programmer to do Objective C and iOS, than a Java Programmer. So classic battle of Java vs C++ still continues with Smartphone application development. Any way, let's come to the topic of How Android works internally. . If you are looking for some good books to start with Android, you can also check out Professional Android 4 Application Development and Ian F. Darwin’s Android Cookbook.

How Android works

As I said Android uses Java for application development. So you can code your Android apps using Java API provided by Google, and it compiles into class files. Similarity ends here, Android doesn't use Java Virtual machine (JVM) for executing class files, instead it uses Dalvik virtual machine, which is not a true JVM and doesn't operate on Java byte code. In order to run on Dalvik Virtual machines, class files are further compiled into Dalvik Executable or DEX format. After conversion to DEX format, class files along with other resources are bundled into Android Package (APK) for distribution and installation into various devices. Key thing to know is that, Dalvik VM is based on subset of the Apache Harmony Project for its core class library, which means it doesn't support all J2SE API. If you are using Eclipse IDE for coding Android Apps, then you don't need to worry much because, it will help you with code completion. Now let's see How Android Application runs on device?

How Android apps runs on Device

If you are familiar with Linux and concept of process, then it's easy to understand how android applications runs. By default, Each Android application is assigned a unique user id by the Android operating system. After starting android application, they run on there own process, inside there own virtual machine. Android operating system manages starting and shutting down the application process, whenever required. This means, each android application runs in isolation with other, but they can certainly request access to hardware and other system resources. If you are familiar with mobile application development, may be in J2ME, then you may know about permissions. So when an android application is installed or started, it request necessary permission required to connect internet, phone book and other system resource. User explicitly provides grant these permissions, or it may deny. All these permissions are defined in manifest file of Android application. Unlike Java Manifest file, Android manifest is an XML file, which lists all the components of apps, and settings for those components. Four major components of Android application development is Activities, Services, Content Providers and Broadcast Receivers. Activity is most common of them, as it represent a single screen in Android Application. For example, in an Android Game, you can have multiple screens for login, high score, instructions and game screen. Each of these screen represent different Activities inside your app. Similar to Java, good thing about Android is that it manages certain task on behalf of developer, one of them is creating activity object. Activities are managed by System, when you want to start an activity, you call startActivity() method which takes an Intent object. In response to this call, System can either create new activity object or reuse an existing one. Just like Garbage collection in Java, manages a critical task or reclaiming memory, Android manages starting, stopping, creating and destroying of apps by themselves. You may think it's restrictive, but it's not. Android provides life-cycle events, which you can override to interact with this process.

That's all on How Android works.  Android is definitely worth learning for Java programmer, as it uses Java, you can reuse your existing knowledge of Java programming techniques, design patterns and best practices to code a good android app. Of course, you need to adapt some Android specific things like, but those will come along. So, what are you waiting for, go and explore more about Android and write an Android HelloWorld application. Finally you can also take a look some of the best book to start with Android development, Professional Android 4 Application Development and Android Cookbook by Ian F. Darwin.

Android SQLite Database Tutorial

Android SQLite Database Tutorial

Android provides several ways to store user and app data. SQLite is one way of storing user data. SQLite is a very light weight database which comes with Android OS. In this tutorial I’ll be discussing how to write classes to handle all SQLite operations.

In this tutorial I am taking an example of storing user contacts in SQLite database. I am using a table called Contacts to store user contacts. This table contains three columns id (INT), name (TEXT),phone_number(TEXT).

Contacts Table Structure

Writing Contact Class

Before you go further you need to write your Contact class with all getter and setter methods to maintain single contact as an object.

Contact.java

package com.androidkiran.androidsqlite;

public class Contact {

     

    //private variables

    int _id;

    String _name;

    String _phone_number;

     

    // Empty constructor

    public Contact(){

         

    }

    // constructor

    public Contact(int id, String name, String _phone_number){

        this._id = id;

        this._name = name;

        this._phone_number = _phone_number;

    }

// constructor

    public Contact(String name, String _phone_number){

        this._name = name;

        this._phone_number = _phone_number;

    }

    // getting ID

    public int getID(){

        return this._id;

    }

     

    // setting id

    public void setID(int id){

        this._id = id;

    }

     

    // getting name

    public String getName(){

        return this._name;

    }

     

    // setting name

    public void setName(String name){

        this._name = name;

    }

     

    // getting phone number

    public String getPhoneNumber(){

        return this._phone_number;

    }

     

    // setting phone number

    public void setPhoneNumber(String phone_number){

        this._phone_number = phone_number;

    }

}

Writing SQLite Database Handler Class

  We need to write our own class to handle all database CRUD(Create, Read, Update and Delete) operations.

1. Create a new project by going to File ⇒ New Android Project.
2. Once the project is created, create a new class in your project src directory and name it asDatabaseHandler.java ( Right Click on src/package ⇒ New ⇒ Class)
3. Now extend your DatabaseHandler.java class from SQLiteOpenHelper.

public class DatabaseHandler extends SQLiteOpenHelper {

4. After extending your class from SQLiteOpenHelper you need to override two methods onCreate() andonUpgrage()
onCreate() – These is where we need to write create table statements. This is called when database is created.
onUpgrade() – This method is called when database is upgraded like modifying the table structure, adding constraints to database etc.,

public class DatabaseHandler extends SQLiteOpenHelper {

    // All Static variables

    // Database Version

    private static final int DATABASE_VERSION = 1;

    // Database Name

    private static final String DATABASE_NAME = "contactsManager";

    // Contacts table name

    private static final String TABLE_CONTACTS = "contacts";

    // Contacts Table Columns names

    private static final String KEY_ID = "id";

    private static final String KEY_NAME = "name";

    private static final String KEY_PH_NO = "phone_number";

    public DatabaseHandler(Context context) {

        super(context, DATABASE_NAME, null, DATABASE_VERSION);

    }

// Creating Tables

    @Override

    public void onCreate(SQLiteDatabase db) {

        String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("

                + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"

                + KEY_PH_NO + " TEXT" + ")";

        db.execSQL(CREATE_CONTACTS_TABLE);

    }

    // Upgrading database

    @Override

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        // Drop older table if existed

        db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);

        // Create tables again

        onCreate(db);

    }

⇒All CRUD Operations (Create, Read, Update and Delete)

Now we need to write methods for handling all database read and write operations. Here we are implementing following methods for our contacts table.

// Adding new contact

public void addContact(Contact contact) {}

// Getting single contact

public Contact getContact(int id) {}

// Getting All Contacts

public List<Contact> getAllContacts() {}

// Getting contacts Count

public int getContactsCount() {}

// Updating single contact

public int updateContact(Contact contact) {}

// Deleting single contact

public void deleteContact(Contact contact) {}

⇒Inserting new Record

The addContact() method accepts Contact object as parameter. We need to build ContentValues parameters using Contact object. Once we inserted data in database we need to close the database connection.

addContact()

//Adding new Contact

public void addContact(Contact contact) {

    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();

    values.put(KEY_NAME, contact.getName()); // Contact Name

    values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone Number

    // Inserting Row

    db.insert(TABLE_CONTACTS, null, values);

    db.close(); // Closing database connection

}

⇒Reading Row(s)

The following method getContact() will read single contact row. It accepts id as parameter and will return the matched row from the database.

Get Contact()

//Getting single contact

public Contact getContact(int id) {

    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,

            KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",

            new String[] { String.valueOf(id) }, null, null, null, null);

    if (cursor != null)

        cursor.moveToFirst();

    Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),

            cursor.getString(1), cursor.getString(2));

    // return contact

    return contact;

}

getAllContacts() will return all contacts from database in array list format of Contact class type. You need to write a for loop to go through each contact.

getAllContacts()

//Getting all contacts

public List<Contact> getAllContacts() {

    List<Contact> contactList = new ArrayList<Contact>();

    // Select All Query

    String selectQuery = "SELECT  * FROM " + TABLE_CONTACTS;

    SQLiteDatabase db = this.getWritableDatabase();

    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list

    if (cursor.moveToFirst()) {

        do {

            Contact contact = new Contact();

            contact.setID(Integer.parseInt(cursor.getString(0)));

            contact.setName(cursor.getString(1));

            contact.setPhoneNumber(cursor.getString(2));

            // Adding contact to list

            contactList.add(contact);

        } while (cursor.moveToNext());

    }

    // return contact list

    return contactList;

}

getContactsCount() will return total number of contacts in SQLite database.

getContactsCount()

// Getting Contacts count

public int getContactsCount() {

        String countQuery = "SELECT  * FROM " + TABLE_CONTACTS;

        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.rawQuery(countQuery, null);

        cursor.close();

        // return count

        return cursor.getCount();

    }

⇒Updating Record

updateContact() will update single contact in database. This method accepts Contact class object as parameter.

updateContact()

// Updating single contact

public int updateContact(Contact contact) {

    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();

    values.put(KEY_NAME, contact.getName());

    values.put(KEY_PH_NO, contact.getPhoneNumber());

    // updating row

    return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",

            new String[] { String.valueOf(contact.getID()) });

}

⇒Deleting Record

deleteContact() will delete single contact from database.

deleteContact()

//Deleting single contact.

public void deleteContact(Contact contact) {

    SQLiteDatabase db = this.getWritableDatabase();

    db.delete(TABLE_CONTACTS, KEY_ID + " = ?",

            new String[] { String.valueOf(contact.getID()) });

    db.close();

}

Complete DatabaseHandler.java Code:

DatabaseHandler.java

package com.androidkiran.androidsqlite;

import java.util.ArrayList;

import java.util.List;

import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHandler extends SQLiteOpenHelper {

    // All Static variables

    // Database Version

    private static final int DATABASE_VERSION = 1;

    // Database Name

    private static final String DATABASE_NAME = "contactsManager";

    // Contacts table name

    private static final String TABLE_CONTACTS = "contacts";

    // Contacts Table Columns names

    private static final String KEY_ID = "id";

    private static final String KEY_NAME = "name";

    private static final String KEY_PH_NO = "phone_number";

    public DatabaseHandler(Context context) {

        super(context, DATABASE_NAME, null, DATABASE_VERSION);

    }

    // Creating Tables

    @Override

    public void onCreate(SQLiteDatabase db) {

        String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("

                + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"

                + KEY_PH_NO + " TEXT" + ")";

        db.execSQL(CREATE_CONTACTS_TABLE);

    }

    // Upgrading database

    @Override

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        // Drop older table if existed

        db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);

        // Create tables again

        onCreate(db);

    }

    /**

     * All CRUD(Create, Read, Update, Delete) Operations

     */

    // Adding new contact

    void addContact(Contact contact) {

        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();

        values.put(KEY_NAME, contact.getName()); // Contact Name

        values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone

        // Inserting Row

        db.insert(TABLE_CONTACTS, null, values);

        db.close(); // Closing database connection

    }

    // Getting single contact

    Contact getContact(int id) {

        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,

                KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",

                new String[] { String.valueOf(id) }, null, null, null, null);

        if (cursor != null)

            cursor.moveToFirst();

        Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),

                cursor.getString(1), cursor.getString(2));

        // return contact

        return contact;

    }

     

    // Getting All Contacts

    public List<Contact> getAllContacts() {

        List<Contact> contactList = new ArrayList<Contact>();

        // Select All Query

        String selectQuery = "SELECT  * FROM " + TABLE_CONTACTS;

        SQLiteDatabase db = this.getWritableDatabase();

        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list

        if (cursor.moveToFirst()) {

            do {

                Contact contact = new Contact();

                contact.setID(Integer.parseInt(cursor.getString(0)));

                contact.setName(cursor.getString(1));

                contact.setPhoneNumber(cursor.getString(2));

                // Adding contact to list

                contactList.add(contact);

            } while (cursor.moveToNext());

        }

        // return contact list

        return contactList;

    }

    // Updating single contact

    public int updateContact(Contact contact) {

        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();

        values.put(KEY_NAME, contact.getName());

        values.put(KEY_PH_NO, contact.getPhoneNumber());

        // updating row

        return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",

                new String[] { String.valueOf(contact.getID()) });

    }

    // Deleting single contact

    public void deleteContact(Contact contact) {

        SQLiteDatabase db = this.getWritableDatabase();

        db.delete(TABLE_CONTACTS, KEY_ID + " = ?",

                new String[] { String.valueOf(contact.getID()) });

        db.close();

    }

    // Getting contacts Count

    public int getContactsCount() {

        String countQuery = "SELECT  * FROM " + TABLE_CONTACTS;

        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.rawQuery(countQuery, null);

        cursor.close();

        // return count

        return cursor.getCount();

    }

}

Usage:

AndroidSQLiteTutorialActivity

package com.androidkiran.androidsqlite;

import java.util.List;

import android.app.Activity;

import android.os.Bundle;

import android.util.Log;

import android.widget.TextView;

public class AndroidSQLiteTutorialActivity extends Activity {

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

         

        DatabaseHandler db = new DatabaseHandler(this);

         

        /**

         * CRUD Operations

         * */

        // Inserting Contacts

        Log.d("Insert: ", "Inserting ..");

        db.addContact(new Contact("Ravi", "9100000000"));       

        db.addContact(new Contact("Srinivas", "9199999999"));

        db.addContact(new Contact("Tommy", "9522222222"));

        db.addContact(new Contact("Karthik", "9533333333"));

         

        // Reading all contacts

        Log.d("Reading: ", "Reading all contacts..");

        List<Contact> contacts = db.getAllContacts();      

         

        for (Contact cn : contacts) {

            String log = "Id: "+cn.getID()+" ,Name: " + cn.getName() + " ,Phone: " + cn.getPhoneNumber();

                // Writing Contacts to log

        Log.d("Name: ", log);

    }

    }

}