Dynamic Button in Kotlin

Last Updated : 11 Sep, 2021

In Android, a button represent something that can be clicked by the user to perform some action.
Firstly, we need to create a project in Android Studio. To do follow these steps:

Click on File, then New, and then New Project, and give name whatever you like:

Click on File, then New, and then New Project, and give name whatever you like
Then, select Kotlin language Support and click next button.
Select minimum SDK, whatever you need.
Select Empty activity and then click finish.

After doing this you will see some directories on the left hand side after your project/gradle is finished loading. It should look like this:

Second step is to design our layout page. Go to app > res > layout and paste the following code:

Modify activity_main.xml file

XML

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">
 
    <LinearLayout
            android:id="@+id/layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:orientation="vertical">
    </LinearLayout>
 
</android.support.constraint.ConstraintLayout>

After setting up the design our final step is to code our progress bar. Open app/src/main/java/yourPackageName/MainActivity.kt

Create Button in MainActivity.kt file

First of all, we define the button and set its attributes.

val button = Button(this)
        // setting layout_width and layout_height using layout parameters
        button.layoutParams = LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
 ViewGroup.LayoutParams.WRAP_CONTENT)

then, add the button in the layout using addView()

       
 val layout = findViewById(R.id.layout) as LinearLayout
 // add Button to LinearLayout
        layout.addView(button)

Java

package com.geeksforgeeks.myfirstkotlinapp
 
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.ViewGroup
import android.widget.Button
import android.widget.LinearLayout
import android.widget.Toast
  
class MainActivity : AppCompatActivity() {
  
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
  
        val layout = findViewById(R.id.layout) as LinearLayout
  
        // creating the button
        val button = Button(this)
        // setting layout_width and layout_height using layout parameters
        button.layoutParams = LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)
        button.text = "WELCOME TO GFG"
        button.setOnClickListener { Toast.makeText(this@MainActivity, "Hello GEEK", Toast.LENGTH_LONG).show() }
  
  
        // add Button to LinearLayout
        layout.addView(button)
    }
}

AndroidManifest.xml file

XML

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="i.apps.button">
  
    <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            android:roundIcon="@mipmap/ic_launcher_round"
            android:supportsRtl="true"
            android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
  
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>
  
</manifest>

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