Android AlertDialog Tutorial

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1- Android AlertDialog

Android AlertDialog is a dialog that displays a message, and support 1, 2 or 3 buttons. It makes it easy to create a dialog with just a few lines of code.
AlertDialog includes 3 areas:
  1. Title area
  2. Content area
  3. Button area
Landscape screen
Portrait screen

Title area

Use the setTitle(), setIcon() methods to set title and icon for the dialog box, which will be viewed in the Title area. Otherwise, use the setCustomTitle(View) method if you would like to have a customized Title area.

Content area

The Content area can display a message, a list of options and so on.

Buttons area

This area has a maximum of 3 buttons: Positive button, Negative button, and Neutral button, in which the first 2 buttons support Text & Icon, while the Neutral button only supports Text, however, you can have the icon displayed with a little trick (See more in the example).

2- Example of AlertDialog (1)

Example preview:
AlertButtonExample0.java
package org.o7planning.alertdialogexample;

import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogExample0 {

    public static void showAlertDialog(final Context context)  {
        final Drawable positiveIcon = context.getResources().getDrawable(R.drawable.icon_positive);
        final Drawable negativeIcon = context.getResources().getDrawable(R.drawable.icon_negative);
        final Drawable neutralIcon = context.getResources().getDrawable(R.drawable.icon_neutral);

        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        // Set Title and Message:
        builder.setTitle("Title").setMessage("This is a message");

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Positive" button with OnClickListener.
        builder.setPositiveButton("Positive", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose positive button",
                        Toast.LENGTH_SHORT).show();
            }
        });
        builder.setPositiveButtonIcon(positiveIcon);

        // Create "Negative" button with OnClickListener.
        builder.setNegativeButton("Negative", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose positive button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });
        builder.setNegativeButtonIcon(negativeIcon);

        // Create "Neutral" button with OnClickListener.
        builder.setNeutralButton("Neutral", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                //  Action for 'NO' Button
                Toast.makeText(context,"You choose neutral button",
                        Toast.LENGTH_SHORT).show();
            }
        });
        builder.setNeutralButtonIcon(neutralIcon); // Not working!!!

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }
}

3- Example of AlertDialog (2)

AlertDialogExample2.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogExample2 {

    public static void showAlertDialog(final Context context)  {
        final Drawable positiveIcon = context.getResources().getDrawable(R.drawable.icon_positive);
        final Drawable negativeIcon = context.getResources().getDrawable(R.drawable.icon_negative);

        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        // Set Title and Message:
        builder.setTitle("Confirmation").setMessage("Do you want to close this app?");

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Yes" button with OnClickListener.
        builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose Yes button",
                        Toast.LENGTH_SHORT).show();
                Activity activity = (Activity) context;
                activity.finish();
            }
        });
        builder.setPositiveButtonIcon(positiveIcon);

        // Create "No" button with OnClickListener.
        builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose No button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });
        builder.setNegativeButtonIcon(negativeIcon);

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }
}

4- Example of AlertDialog (List)

This is an example of the  AlertDialog with a list of different options for the user to select:
AlertDialogListExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogListExample {

    public static void showAlertDialog(final Activity activity)  {
        final Drawable negativeIcon = activity.getResources().getDrawable(R.drawable.icon_negative);

        AlertDialog.Builder builder = new AlertDialog.Builder(activity);

        // Set Title.
        builder.setTitle("Select an Animal");

        // Add a list
        final String[] animals = {"Horse", "Cow", "Camel", "Sheep", "Goat"};
        builder.setItems(animals, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                String animal = animals[which];

                dialog.dismiss(); // Close Dialog
                // Do some thing....
                // For example: Call method of MainActivity.
                Toast.makeText(activity,"You select: " + animal,
                        Toast.LENGTH_SHORT).show();
                // activity.someMethod(animal);
            }
        });

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Cancel" button with OnClickListener.
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(activity,"You choose No button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });
        builder.setNegativeButtonIcon(negativeIcon);

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }

}

5- Example of AlertDialog (Single Choice)

AlertDialogSingleChoiceExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.DialogInterface;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

import java.util.HashSet;
import java.util.Set;

public class AlertDialogSingleChoiceExample {


    public static void showAlertDialog(final Activity activity)  {
        AlertDialog.Builder builder = new AlertDialog.Builder(activity);

        // Set Title.
        builder.setTitle("Select an Animal");

        // Add a list
        final String[] animals = {"Horse", "Cow", "Camel", "Sheep", "Goat"};

        int checkedItem = 3; // Sheep
        final Set<String> selectedItems = new HashSet<String>();
        selectedItems.add(animals[checkedItem]);

        builder.setSingleChoiceItems(animals, checkedItem, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // Do Something...
                selectedItems.clear();
                selectedItems.add(animals[which]);
            }
        });

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Yes" button with OnClickListener.
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                if(selectedItems.isEmpty()) {
                    return;
                }
                String animal = selectedItems.iterator().next();

                // Close Dialog
                dialog.dismiss();
                // Do something, for example: Call a method of Activity...
                Toast.makeText(activity,"You select " + animal,
                        Toast.LENGTH_SHORT).show();

            }
        });

        // Create "Cancel" button with OnClickListener.
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(activity,"You choose Cancel button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }

}

6- Example of AlertDialog (Multi Choice)

AlertDialogMultiChoiceExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.DialogInterface;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

import java.util.HashSet;
import java.util.Set;

public class AlertDialogMultiChoiceExample {


    public static void showAlertDialog(final Activity activity)  {
        AlertDialog.Builder builder = new AlertDialog.Builder(activity);

        // Set Title.
        builder.setTitle("Select an Animal");

        // Add a list
        final String[] animals = {"Horse", "Cow", "Camel", "Sheep", "Goat"};

        final boolean[] checkedInfos = new boolean[]{false, false, false, true, false}; // Sheep


        builder.setMultiChoiceItems(animals, checkedInfos, new DialogInterface.OnMultiChoiceClickListener()  {
            @Override
            public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                checkedInfos[which] = isChecked;
            }
        });

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Yes" button with OnClickListener.
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                // Close Dialog
                dialog.dismiss();

                String s= null;
                for(int i=0; i< animals.length;i++)  {
                    if(checkedInfos[i]) {
                        if(s == null)  {
                            s = animals[i];
                        } else {
                            s+= ", " + animals[i];
                        }
                    }
                }
                s = s == null? "":s;

                // Do something, for example: Call a method of Activity...
                Toast.makeText(activity,"You select " + s,
                        Toast.LENGTH_SHORT).show();
            }
        });

        // Create "Cancel" button with OnClickListener.
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(activity,"You choose Cancel button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }

}

7- Example of customized Title Area

By applying the  setCustomTitle(View) method, you can customize the  Title area of  AlertDialog:
And probably use  Android Resource File in order to create the interface of the  Title area.
AlertDialog.Builder builder = new AlertDialog.Builder(context);

// Custom Title Area.
LayoutInflater inflater = context.getLayoutInflater();
View view = inflater.inflate(R.layout.layout_custom_title, null);
builder.setCustomTitle(view);
...
        
// Create AlertDialog:
AlertDialog alert = builder.create();
alert.show();
Alright, now let's create a  Layout Resource File:
  • File > New > Android Resource File
    • File Name: layout_custom_title.xml
    • Resource type: Layout
    • Directory name: layout
Then design the interface of the  Title area:
layout_custom_title.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/icon_title" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:background="#E3DCC4"
        android:gravity="center"
        android:text="This is the Title"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />

</androidx.constraintlayout.widget.ConstraintLayout>
AlertDialogCustomTitleExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogCustomTitleExample {

    public static void showAlertDialog(final Activity context)  {
        final Drawable positiveIcon = context.getResources().getDrawable(R.drawable.icon_positive);

        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        // Custom Title Area.
        LayoutInflater inflater = context.getLayoutInflater();
        View view = inflater.inflate(R.layout.layout_custom_title, null);
        builder.setCustomTitle(view);

        // Message.
        builder.setMessage("This is AlertDialog with Custom Title Area");
        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "OK" button with OnClickListener.
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
            }
        });
        builder.setPositiveButtonIcon(positiveIcon);

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }
}

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