How to Add AlertDialog in Android

In this article we will see how to add an AlertDialog in Android.

Procedure

1. Start the Eclipse IDE.
2. Create a new project.
3. Create a MainActivity.java file.
4. Create an activity_main.xml file for layout design.
5. Add a button in XML layout.
6. Then look up the button by its id in the MainActivity.java file.
7. Create an object like this: AlertDialog.Builder a1=new AlertDialog.Builder(this);

The code for the example is given below.

MainActivity.java

package com.example.aadialogtodayyy;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.os.Process;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity implements android.view.View.OnClickListener
{
    Button b1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    b1=(Button) findViewById(R.id.button1);
    b1.setOnClickListener(this);
}
public void adddddd()
{
    AlertDialog.Builder a1=new AlertDialog.Builder(this);
    a1.setTitle("Exit from Abhijeet's Application");
    a1.setMessage("Are u sure ?");
   a1.setIcon(getResources().getDrawable(R.drawable.ic_launcher));
   a1.setPositiveButton("Yes", new OnClickListener() {

public void onClick(DialogInterface dialog, int which) {
    // TODO Auto-generated method stub
    finish();
    }
});
a1.setNegativeButton("No", new OnClickListener() {
    public void onClick(DialogInterface dialog, int which) {
        // TODO Auto-generated method stub
       Process.killProcess(Process.myPid());
    }
});
a1.show();
}
public void onClick(View v) {
    // TODO Auto-generated method stub
    adddddd();
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if(keyCode==KeyEvent.KEYCODE_MENU)
   {
       adddddd();
   }
    // TODO Auto-generated method stub
    return super.onKeyDown(keyCode, event);
  }
}

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" >

  <Button

  android:id="@+id/button1"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:layout_alignParentLeft="true"

  android:layout_alignParentTop="true"

  android:layout_marginLeft="106dp"

  android:layout_marginTop="52dp"

  android:text="Click Here for Exit" />

</RelativeLayout>

 

 Output