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Button in Android - GeeksforGeeks

Button in Android

Last Updated : 12 Jul, 2025

In Android applications, a Button is a user interface that is used to perform some action when clicked or tapped. It is a very common widget in Android and developers often use it. This article demonstrates how to create a button in Android Studio.

Class Hierarchy of the Button Class in Kotlin

kotlin.Any
↳ android.view.View
↳ android.widgets.TextView
↳ android.widget.Button

XML Attributes of Button Widget

XML Attributes

Description

android:id Used to specify the id of the view. android:text Used to the display text of the button. android:textColor Used to the display color of the text. android:textSize Used to the display size of the text. android:textStyle Used to the display style of the text like Bold, Italic, etc. android:textAllCaps Used to display text in Capital letters. android:background Used to set the background of the view. android:padding Used to set the padding of the view. android:visibility Used to set the visibility of the view. android:gravity Used to specify the gravity of the view like center, top, bottom, etc Step by Step Implementation of Button in Android

In this example step by step demonstration of creating a Button will be covered. The application will consist of a button that displays a toast message when the user taps on it.

Step 1: Create a new project

Click on File, then New => New Project.
Choose “Empty Activity” for the project template.
Select language as Kotlin.
Select the minimum SDK as per your need.

Step 2: Modify the activity_main.xml file

Add a button widget in the layout of the activity. Below is the code of the activity_main.xml file which does the same.

activity_main.xml: activity_main.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"
    android:background="#168BC34A"
    tools:context=".MainActivity">

    <!-- Button added in the activity -->
    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#4CAF50"
        android:paddingStart="10dp"
        android:paddingEnd="10dp"
        android:text="Button"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Layout:
Step 3: Accessing the button in the MainActivity file

Add functionality of button in the MainActivity file. Here describe the operation to display a Toast message when the user taps on the button. Below is the code to carry out this task.

MainActivity.java


 import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate( Bundle savedInstanceState ) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // storing ID of the button
        // in a variable
        Button button = (Button)findViewById(R.id.button);

        // operations to be performed
        // when user tap on the button
        if (button != null) {
            button.setOnClickListener((View.OnClickListener)(new View.OnClickListener() {
                    public final void onClick(View it) {

                    // displaying a toast message
                    Toast.makeText((Context)MainActivity.this, R.string.message, Toast.LENGTH_LONG).show();
                }
            }));
        }
    }
}

MainActivity.kt


 import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.Toast

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // storing ID of the button
        // in a variable
        val button = findViewById<Button>(R.id.button)

        // operations to be performed
        // when user tap on the button
        button?.setOnClickListener()
        {
            // displaying a toast message
            Toast.makeText(this@MainActivity, R.string.message, Toast.LENGTH_LONG).show() }
    }
}

Output:

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