AlertDialog in Android

What is Dialog?
A dialog is a small window that prompts the user to make a decision or enter additional information. A dialog does not fill the screen and is normally used for modal events that require users to take an action before they can proceed.

The Dialog class is the base class for dialogs, but you should avoid instantiating Dialog directly. Instead, use one of the following subclasses:

1.AlertDialog
2.ProgressDialog
3.TimePickerDialog
4.DatePickerDialog


ScreenShots:

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"

    tools:context=".MainActivity" >

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="107dp"

        android:text="Alert" />

</RelativeLayout>

MainActivity.java:

package com.example.alertdialog;

import android.app.Activity;

import android.app.AlertDialog;

import android.content.DialogInterface;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class MainActivity extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

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

b.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

builder.setTitle("Exit");

builder.setMessage("are you sure");

builder.setPositiveButton("ok", new DialogInterface.OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

// TODO Auto-generated method stub

finish();

}

});

builder.setNegativeButton("cancel", new DialogInterface.OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

// TODO Auto-generated method stub

}

});

AlertDialog alert = builder.create();

alert.show();

}

});

}

 

}