Here I have created AlertDialog function in android. We can use alertdialog for choice to continue or discontinue. AlertDialog can be used to display the dialog message with OK and Cancel buttons. Android AlertDialog is the subclass of Dialog class. In the below code example, I have described how to make AlertDialog in android.

Step(1)-activity_main.xml

<RelativeLayout xmlns:androclass="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" >  

    <TextView  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_centerHorizontal="true"  
        android:layout_centerVertical="true"  
        android:text="Welcome_evon" />  

</RelativeLayout>  

Step(2)-strings.xml

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

    <string name="app_name">alertdialog</string>  
    <string name="Welcome_evon">Hello world!</string>  
    <string name="menu_settings">Settings</string>  
    <string name="dialog_message">Welcome to Evon</string>  

   <string name="dialog_title">AlertDialog</string>  
</resources> 

Step(3)- MainActivity.java

 public class MainActivity extends Activity {  

    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  

        AlertDialog.Builder builder = new AlertDialog.Builder(this);  
        //Uncomment the below code to Set the message and title from the strings.xml file  
        //builder.setMessage(R.string.dialog_message) .setTitle(R.string.dialog_title);  

        //Setting message manually and performing action on button click  
        builder.setMessage("Do you want to close this app?")  
            .setCancelable(false)  
            .setPositiveButton("Yes", new DialogInterface.OnClickListener() {  
                public void onClick(DialogInterface dialog, int id) {  
                finish();  
                }  
            })  
            .setNegativeButton("No", new DialogInterface.OnClickListener() {  
                public void onClick(DialogInterface dialog, int id) {  
                //  Action for 'NO' Button  
                dialog.cancel();  
             }  
            });  
        AlertDialog alert = builder.create();  
        alert.setTitle("Are u sure");  
        alert.show();  
        setContentView(R.layout.activity_main);  
    }  

    @Override  
    public boolean onCreateOptionsMenu(Menu menu) {  
        getMenuInflater().inflate(R.menu.activity_main, menu);  
        return true;  
    }  

}