Android AlertDialog Example

Android AlertDialog can be used to display the dialog message with OK and Cancel buttons. It can be used to interrupt and ask the user about his/her choice to continue or discontinue.

Android AlertDialog is composed of three regions: title, content area and action buttons.

Android AlertDialog is the subclass of Dialog class.

Android AlertDialog Example

Let's see a simple example of android alert dialog.

activity_main.xml

You can have multiple components, here we are having only a textview.

File: activity_main.xml

1. <RelativeLayout xmlns:androclass="http://schemas.android.com/apk/res/android"  
2.     xmlns:tools="http://schemas.android.com/tools"  
3.     android:layout_width="match_parent"  
4.     android:layout_height="match_parent"  
5.     tools:context=".MainActivity" >  
6.   
7.     <TextView  
8.         android:layout_width="wrap_content"  
9.         android:layout_height="wrap_content"  
10.         android:layout_centerHorizontal="true"  
11.         android:layout_centerVertical="true"  
12.         android:text="@string/hello_world" />  
13.   
14. </RelativeLayout>  

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strings.xml

Optionally, you can store the dialog message and title in the strings.xml file.

File: strings.xml

1. <?xml version="1.0" encoding="utf-8"?>  
2. <resources>  
3.   
4.     <string name="app_name">alertdialog</string>  
5.     <string name="hello_world">Hello world!</string>  
6.     <string name="menu_settings">Settings</string>  
7.     <string name="dialog_message">Welcome to Alert Dialog</string>  
8.    
9.    <string name="dialog_title">Alert Dialog</string>  
10. </resources>  

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Activity class

Let's write the code to create and show the AlertDialog.

File: MainActivity.java

1. package com.example.alertdialog;  
2.   
3. import android.os.Bundle;  
4. import android.app.Activity;  
5. import android.app.AlertDialog;  
6. import android.content.DialogInterface;  
7. import android.view.Menu;  
8.   
9. public class MainActivity extends Activity {  
10.   
11.     @Override  
12.     protected void onCreate(Bundle savedInstanceState) {  
13.         super.onCreate(savedInstanceState);  
14.           
15.         AlertDialog.Builder builder = new AlertDialog.Builder(this);  
16.         //Uncomment the below code to Set the message and title from the strings.xml file  
17.         //builder.setMessage(R.string.dialog_message) .setTitle(R.string.dialog_title);  
18.           
19.         //Setting message manually and performing action on button click  
20.         builder.setMessage("Do you want to close this application ?")  
21.             .setCancelable(false)  
22.             .setPositiveButton("Yes", new DialogInterface.OnClickListener() {  
23.                 public void onClick(DialogInterface dialog, int id) {  
24.                 finish();  
25.                 }  
26.             })  
27.             .setNegativeButton("No", new DialogInterface.OnClickListener() {  
28.                 public void onClick(DialogInterface dialog, int id) {  
29.                 //  Action for 'NO' Button  
30.                 dialog.cancel();  
31.              }  
32.             });  
33.   
34.         //Creating dialog box  
35.         AlertDialog alert = builder.create();  
36.         //Setting the title manually  
37.         alert.setTitle("AlertDialogExample");  
38.         alert.show();  
39.         setContentView(R.layout.activity_main);  
40.     }  
41.   
42.     @Override  
43.     public boolean onCreateOptionsMenu(Menu menu) {  
44.         // Inflate the menu; this adds items to the action bar if it is present.  
45.         getMenuInflater().inflate(R.menu.activity_main, menu);  
46.         return true;  
47.     }  
48.   
49. }  

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Output: