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Button in Android

Last Updated : 17 Aug, 2021

In Android applications, a Button is a user interface element used to trigger actions when clicked or tapped. Buttons are widely utilized in Android development. This guide illustrates how to create a button within Android Studio.

Button

The Class Hierarchy of the Button Class in Kotlin

Button in Kotlin - Software Development

XML Attributes of Button Widget

XML AttributesDescription
android:idUsed to specify the id of the view.
android:textUsed to display text on the button.
android:textColorUsed to set the text color.
android:textSizeUsed to set the text size.
android:textStyleUsed to set the text style such as Bold or Italic.
android:textAllCapsUsed to display text in capital letters.
android:backgroundUsed to set the background of the view.
android:paddingUsed to set the padding of the view.
android:visibilityUsed to set the visibility of the view.
android:gravityUsed to specify the gravity of the view, such as center, top, or bottom.

Example

In this example, we will walk through the step-by-step process of creating a Button. The demonstration will showcase an application with a button that triggers a toast message when tapped by the user.

Note: The following steps are demonstrated in Android Studio version 4.0

Note:

Step 1: Create a new project

  • Click on File, then New => New Project.
  • Choose "Empty Activity" for the project template.
  • Select Kotlin as the programming language.
  • Choose the minimum SDK version based on your requirements.
  • Step 2: Modify the strings.xml file

    Navigate to the strings.xml file within the "values" directory of the resource folder. This file stores all strings used in the application. Below is the relevant code snippet.

    strings.xml"values"resource folder
      XML

    Ensure you follow each point to create a functional Button in your Android application.

    Button Implementation in Kotlin

    • Implementing a Button in Kotlin involves modifying the activity_main.xml file.
    • To add a button widget in the layout, specific code changes are necessary.

    Modifying the activity_main.xml File

    • Within the activity_main.xml file, adjustments are made to include the button widget.
    • The XML code snippet below demonstrates how to add a button in the activity layout:

    Accessing the Button in the MainActivity File

    • After button implementation, accessing the button functionality is essential in the MainActivity file.
    • This step involves interacting with the button element within the codebase to perform desired actions.
    Summarized Notes

    Step 4: Accessing the button in the MainActivity file

    • Add functionality of button in the MainActivity file. This involves defining operations to display a Toast message when the user taps on the button.

    MainActivity

    • Java
    • Kotlin

    Below is the code snippet for implementing the button functionality in the MainActivity file:

    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 taps on the button         if (button != null) {             button.setOnClickListener(new View.OnClickListener() {                 public void onClick(View it) {                    Toast.makeText((Context) MainActivity.this, R.string.message, Toast.LENGTH_LONG).show();                 }      &

    Explaining Android Development with Kotlin

    • Android Development with Kotlin is an exciting journey into the world of mobile app creation.
    • Mastering this skill allows you to create powerful, user-friendly applications.
    • Using Kotlin as the programming language offers advantages like concise code and improved app performance.

    Key Components of Android Development

    • AppCompatActivity: An important class in Android development that provides compatibility features for newer versions of Android.
    • Bundle: Used for passing data between various Android activities.
    • Button: A UI element that users can interact with by tapping on it.
    • Toast: A small pop-up message that provides feedback to the user.

    Understanding MainActivity Class

    • MainActivity : The main entry point for an Android app, extending AppCompatActivity.
    • onCreate: A method where initial setup for the activity is done.
    • setContentView: Sets the layout resource for the activity.
    • findViewById: Locates a view in the layout by its ID.
    • setOnClickListener: Sets a listener to be invoked when the button is tapped.
    • Toast.makeText: Creates a new Toast with a message to display.

    Output:

    Video Player00:0000:07Use Up/Down Arrow keys to increase or decrease volume.

    Ready to embark on an exciting journey into the world of Android Development with Kotlin? It's time to make a change and dive into a fantastic learning experience with our Mastering Android Development with Kotlin From Beginner to Pro - Self Paced!

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