Button in Android (original) (raw)

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	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 `

<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() }
}

}