In this article, we will learn about android Button using Kotlin. We will go through various example that demonstrates how to use different attributes of Button. For example, set id, text, font, font-size etc. in button.

In this article, we will get answer to questions like –

• What is Button?
• Why should we consider Button while designing ui for any app?
• What are possibilities using Button while designing ui? etc.

Let’s have a quick demo of things we want to cover in this tutorial –

Output

Tutorialwing Android Button Using Kotlin Output

Video Output

Getting Started

Android Button can be defined as below –

Android Button is an user interface that are used to perform some action when clicked or tapped.

Now, how do we use Button in android application ?

Creating New Project

At first, we will create an application.
So, follow steps below to create any android project in Kotlin –

Newbie in Android ?

Some very important concepts (Recommended to learn before you move ahead)

• Install Android Studio
• Create New Project in Android Studio
• Android Project Structure
• Run / Debug / Test Android App

Before we move ahead, we need to setup for viewBinding to access Android Button Using Kotlin file without using findViewById() method.

Setup ViewBinding

Add viewBinding true in app/build.gradle file.

 
 android { 
 	// OTHER CODE... 
 	buildFeatures { 
 		viewBinding true 
 	} 
 } 
 

Now, set content in activity using view binding.
Open MainActivity.kt file and write below code in it.

 
 class MainActivity : AppCompatActivity() { 
 	
 	private lateinit var binding: ActivityMainBinding 
 	
 	override fun onCreate(savedInstanceState: Bundle?) { 
 		super.onCreate(savedInstanceState) 
 		binding = ActivityMainBinding.inflate(layoutInflater) 
 		val view = binding.root 
 		setContentView(view) 
 	} 
 } 
 

Now, we can access view in Kotlin file without using findViewById() method.

Using Button in Kotlin

Follow steps below to use Button in newly created project –

• Open res/layout/activity_main.xml file. Then, add below code in it –

  <?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"
      tools:context=".MainActivity">
  
      <Button
          android:id="@+id/button"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="Button"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent" />
  
  </androidx.constraintlayout.widget.ConstraintLayout>
  

• We can also access it in Kotlin File, MainActivity.kt, as below –

  binding.BUTTON_ID
  

Now, run the application. We will get output as below –

Different Attributes of Button in XML

Now, we will see how to use different attributes of Android Button using Kotlin to customise it –

Set Id of Button

Many a time, we need id of View to access it in kotlin file or create ui relative to that view in xml file. So, we can set id of Button using android:id attribute like below –

    <Button
        android:id="@+id/buttonID"
        />

Here, we have set id of Button as buttonID using android:id=”” attribute. So, if we need to reference this Button, we need to use this id – buttonID.
Learn to Set ID of Button Dynamically

Set Width of Button

We use android:layout_width=”” attribute to set width of Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        />

Width can be either “MATCH_PARENT” or “WRAP_CONTENT” or any fixed value (like 20dp, 30dp etc.).
Learn to Set Width of Button Dynamically

Set Height of Button

We use android:layout_height=”” attribute to set height of Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

Height can be either “MATCH_PARENT” or “WRAP_CONTENT” or any fixed value.
Learn to Set Height of Button Dynamically

Set Padding of Button

We use android:padding=”” attribute to set padding of Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        />

Here, we have set padding of 10dp in Button using android:padding=”” attribute.
Learn to Set Padding of Button Dynamically

Set Margin of Button

We use android:layout_margin=”” attribute to set margin of Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        />

Here, we have set margin of 10dp in Button using android:layout_margin=”” attribute.
Learn to Set Margin of Button Dynamically

Set Background of Button

We use android:background=”” attribute to set background of Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#ff0000"
        />

Here, we have set background of color #ff0000 in Button using android:background=”” attribute.
Learn to Set Background of Button Dynamically

Set Visibility of Button

We use android:visibility=”” attribute to set visibility of Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        />

Here, we have set visibility of Button using android:visiblity=”” attribute. Visibility can be of three types – gone, visible and invisible
Learn to Set Visibility of Button Dynamically

Set Text of Button

We use android:text=”” attribute to set text of Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        />

Here, we have set text (“Hello Tutorialwing”) in Button using android:text=”” attribute.
Similarly, we can set any text using this attribute.
Learn to Set Text of Button Dynamically

Set Color of Text in Button

We use android:textColor=”” attribute to set color of text in Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textColor="#ffffff"     
        />

Here, we have set color (#ffffff i.e. white) of text (“Hello Tutorialwing”) in Button using android:textColor=”” attribute. Similarly, we can set any color using this attribute.
Learn to Set Color of Button Dynamically

Set Gravity of Button

We use android:gravity=”” attribute to set gravity of text in Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:gravity="center_horizontal"
        />

Here, we have set gravity of text in Button using android:gravity=”” attribute. Attribute value can be – “center_horizontal”, “center”, “center_vertical” etc.
Learn to Set Gravity of Button Dynamically

Set Text in Uppercase, Lowercase

If we need to show text of Button in uppercase or lowercase etc.

Set text in uppercase

We can use android:textAllCaps=”true” attribute to set text in uppercase. We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textAllCaps="true"
        />

Attribute android:textAllCaps=”true” sets text in uppercase. So, HELLO TUTORIALWING is set in Button.

By default, false is set in this attribute. So, Whatever value is written in android:text=”” attribute, it will be set as it is. For example,

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textAllCaps="false"
        />

Above code will set Hello Tutorialwing to Button.

How do we set text in lowercase?

Answer –

• In xml file – write all the text in lowercase.
• In kotlin file – take text as string. Then, convert it in lowercase. Then, set it to Button.

Learn to Set Text in Uppercase or Lowercase Dynamically

Set Size of Text in Button

We use android:textSize=”” attribute to set size of text in Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textSize="20sp"
        />

Here, we have set size of text in Button using android:textSize=”” attribute.
Learn to Set Size of Text of Button Dynamically

Set Style (Bold/italic) of Text in Button

We use android:textStyle=”” attribute to set style (bold, italic etc.) of text in Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textStyle="bold"
        />

Here, we have set style of text in Button using android:textStyle=”” attribute. This attribute can take bold, italic or normal.
Learn to Set Style of Text of Button Dynamically

Set Letter Spacing of Text in Button

We use android:letterSpacing=”” attribute to set spacing between letters of text in Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:letterSpacing="1"
        />

Here, we have set spacing between letters of text in Button using android:letterSpacing=”” attribute.
Learn to Set Letter Spacing of Text of Button Dynamically

Set Typeface of Text in Button

We use android:typeface=”” attribute to set typeface in Button.
We can do it as below –

    <Button
        android:id="@+id/buttonID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:typeface="sans"
        />

Here, we have set typeface of text in Button using android:typeface=”” attribute. This attribute can take values – “sans”, “normal”, “monospace” or “normal”.
Learn to Set Typeface of Button Dynamically

Set fontFamily of Text in Button

We use android:fontFamily=”” attribute to set fontFamily of text in Button.
We can do it as below –

    <Button
        android:id="@+id/Button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:fontFamily="sans-serif"
        />

Here, we have set fontFamily (Here, sans-serif) of text in Button using android:fontFamily=”sans-serif” attribute.

Till now, we have see how to use android Button using Kotlin. We have also gone through different attributes of TextView to perform certain task. Let’s have a look at list of such attributes and it’s related task.

Different Attributes of Android Button Widget

Below are the various attributes that are used to customise android Button Widget. However, you can check the complete list of attributes of Button in it’s official documentation site. Here, we are going to list some of the important attributes of this widget –

We have seen different attributes of Button and how to use it. If you wish to visit post to learn more about it

Thus, we have seen what is Button, how can we use android Button using Kotlin ? etc. We also went through different attributes of android Button.