Alert Dialogs in android apps

Learn how to create alert dialogs in android apps. We can get decisions and information from user through these alert dialogs.

MainActivity.java

 package com.singh.jassi.alertdialog;  
 import android.content.DialogInterface;  
 import android.support.v7.app.AlertDialog;  
 import android.support.v7.app.AppCompatActivity;  
 import android.os.Bundle;  
 import android.view.View;  
 import android.widget.Button;  
 import android.widget.Toast;  
 public class MainActivity extends AppCompatActivity {  
   public Button button;  
   @Override  
   protected void onCreate(Bundle savedInstanceState) {  
     super.onCreate(savedInstanceState);  
     setContentView(R.layout.activity_main);  
     button=(Button)findViewById(R.id.button);  
   }  
   public void my_dialog(View view)  
   {  
     AlertDialog.Builder builder =new AlertDialog.Builder(MainActivity.this);  
     builder.setIcon(R.mipmap.ic_launcher);  
     builder.setTitle("Alert Dialog");  
     builder.setMessage("Select your option yes/no");  
     builder.setPositiveButton("Yes",new DialogInterface.OnClickListener(){  
       public void onClick(DialogInterface dialog, int num1)  
       {  
         Toast.makeText(MainActivity.this,"You selected yes option",Toast.LENGTH_SHORT).show();  
       }  
     });  
     builder.setNegativeButton("No",new DialogInterface.OnClickListener(){  
       public void onClick(DialogInterface dialog, int num2)  
       {  
         Toast.makeText(MainActivity.this,"You selected no option",Toast.LENGTH_SHORT).show();  
       }  
     });  
     AlertDialog alertDialog =builder.create();  
     alertDialog.show();  
   }  
 }  

activity_main.xml

 <?xml version="1.0" encoding="utf-8"?>  
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
   xmlns:tools="http://schemas.android.com/tools"  
   android:id="@+id/activity_main"  
   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="com.singh.jassi.alertdialog.MainActivity">  
   <TextView  
     android:layout_width="wrap_content"  
     android:layout_height="wrap_content"  
     android:text="Example of an Alert Dialog"  
     android:layout_marginStart="81dp"  
     android:layout_marginTop="43dp"  
     android:layout_alignParentTop="true"  
     android:layout_alignParentStart="true" />  
   <Button  
     android:text="Click me"  
     android:layout_width="wrap_content"  
     android:layout_height="wrap_content"  
     android:id="@+id/button"  
     android:layout_alignParentBottom="true"  
     android:layout_centerHorizontal="true"  
     android:layout_marginBottom="184dp"  
     android:onClick="my_dialog"  
     />  
 </RelativeLayout>  

Create Android virtual device with advance controls - click to create

AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>  
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"  
   package="com.singh.jassi.alertdialog">  
   <application  
     android:allowBackup="true"  
     android:icon="@mipmap/ic_launcher"  
     android:label="@string/app_name"  
     android:supportsRtl="true"  
     android:theme="@style/AppTheme">  
     <activity android:name=".MainActivity">  
       <intent-filter>  
         <action android:name="android.intent.action.MAIN" />  
         <category android:name="android.intent.category.LAUNCHER" />  
       </intent-filter>  
     </activity>  
   </application>  
 </manifest>