AlertDialog in Android is a Dialog box that (prompts) asks a user to take an action. It prompts before proceeding ahead. By Default it appears in the center of the screen. Alert Dialog displays a Title, a Message, and Buttons (up to three). They are Positive (Yes), Negative (No) and Neutral (Cancel) Button. Lets code an example of AlertDialog Android with Kotlin.
AlertDialog Android Kotlin Example:
Alert Dialog prompts the user to take an action before proceeding to the next step. Because it’s a very common feature so you can see it in almost every Android application.
Alert Dialog has following components:
- Title.
- Message.
- Buttons (Positive,Negative and Neutral).
Methods Used in AlertDialog are :
- setTitle()
- setMessage()
- setPositiveButton()
- setNegativeButton()
- setNeutralButton()
1- So, create a new Android Studio Project and name it AlertDialogKotlin. Also, you can name it anything you want. Set Kotlin as your default language. After the project builds go to activity_main.xml file.
2- In your activity_main.xml file, first change the default Constraint Layout to Relative Layout.
3- In your Relative Layout add a Button with wrap_content width and height.
4- After adding some properties to Button, the final activity_main.xml will look like this:
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<?xml version="1.0" encoding="utf-8"?> <RelativeLayout 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" tools:context=".MainActivity"> <Button android:id="@+id/alert_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:textSize="25sp" android:textColor="#000000" android:fontFamily="sans-serif-medium" android:text="Show Alert Dialog BOX" /> </RelativeLayout> |
5- Now, come to your MainActivity. kt file and define a value for our button.
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val alertButton = findViewById<Button>(R.id.alert_button) |
6- Now, we add an OnClickListener on our Button.
7- We use an Instance of AlertDialog.Builder class and hold it in val with the name “builder”. Pass “this” as a context of your MainActivity.
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// Performs action on Button Click alertButton.setOnClickListener{ // Initialization of Instance of AlertDialog.Builder val builder = AlertDialog.Builder(this@MainActivity) |
8- We set the Title and Message of our Alert Dialog.
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// Sets TITLE for Alert Dialog Box builder.setTitle("ALERT DIALOG BOX") // Sets the message you want to display builder.setMessage("Do You Want to Uninstall this application?") |
9- After setting up the Title and Message we will then set up the Buttons.
10- We set up a Positive Button with a ClickListener that will display a Toast message.
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// Creates a positive Button with a Click Listener builder.setPositiveButton("YES"){dialog, which -> // Displays a Toast Message on Positive Button click Toast.makeText(applicationContext,"The Appliciation will be uninstalled now", Toast.LENGTH_SHORT).show() } |
11- Set up a Negative Button with a ClickListener that will display a Toast message.
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// Creates a Negative Button with a Click Listener builder.setNegativeButton("No"){dialog,which -> Toast.makeText(applicationContext, "You Stopped the Uninstall process",Toast.LENGTH_SHORT).show() } |
12- Now we set up a Neutral Button with a ClickListener because the neutral button cancels the dialog. It is used when there is a choice to skip.
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/ Creates a Negative Button with a Click Listener builder.setNegativeButton("No"){dialog,which -> Toast.makeText(applicationContext,"You Stopped the Uninstall process", Toast.LENGTH_SHORT).show() } |
13- Finally create the Dialog and Display it.
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// Creates an Alert Dialog and Displays it on the screen val dialog: AlertDialog = builder.create() dialog.show() |
14- So, The complete final MainActivity.kt file will look like this:
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package com.example.alertdialogkotlin import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.widget.Button import android.widget.Toast import androidx.appcompat.app.AlertDialog class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val alertButton = findViewById<Button>(R.id.alert_button) // Performs action on Button Click alertButton.setOnClickListener{ // Initialization of Instance of AlertDialog.Builder val builder = AlertDialog.Builder(this@MainActivity) // Sets TITLE for Alert Dialog Box builder.setTitle("ALERT DIALOG BOX") // Sets the message you want to display builder.setMessage("Do You Want to Uninstall this application?") // Creates a positive Button with a Click Listener builder.setPositiveButton("YES"){dialog, which -> // Displays a Toast Message on Positive Button click Toast.makeText(applicationContext,"The Appliciation will be uninstalled now", Toast.LENGTH_SHORT).show() } // Creates a Negative Button with a Click Listener builder.setNegativeButton("No"){dialog,which -> Toast.makeText(applicationContext,"You Stopped the Uninstall process", Toast.LENGTH_SHORT).show() } // Creates a Neutral Button with a Click Listener builder.setNeutralButton("Cancel"){_,_ -> Toast.makeText(applicationContext,"You Cancelled.",Toast.LENGTH_SHORT).show() } // Creates an Alert Dialog and Displays it on the screen val dialog: AlertDialog = builder.create() dialog.show() } } } |
So this is it for this tutorial. If you have any queries regarding AlertDialog Android Kotlin then do mention them in comments section below.
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This blog was… how do I say it? Relevant!! Finally I have found something that helped me. Kudos!
thanks @Rodger 🙂
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