Create QR Code Android Kotlin example

Create QR Code Android Kotlin example

1/  Create A New Project .

main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:background="@color/white"
    >

    <LinearLayout
        android:layout_centerInParent="true"
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:padding="16dp">

        <EditText
            android:id="@+id/inputEditText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Enter text to generate QR code"
            android:padding="12dp"
            android:layout_marginBottom="16dp"
            android:background="@android:drawable/editbox_background"
            android:textColorHint="@color/black"
            android:textColor="@color/black"
            />

        <Button
            android:id="@+id/generateButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Generate QR Code"
            android:layout_gravity="center_horizontal"
            android:layout_marginBottom="16dp"/>

        <ImageView
            android:id="@+id/qrCodeImageView"
            android:layout_width="200dp"
            android:layout_height="200dp"
            android:contentDescription="QR Code will be displayed here"
            android:scaleType="fitCenter"
            android:layout_gravity="center"
            />

    </LinearLayout>


</RelativeLayout>

2/ Add dependencies

>>>build.gradle.kts(Module:app)

implementation ("com.google.zxing:core:3.4.1")
implementation ("com.journeyapps:zxing-android-embedded:4.3.0")

3/MainActivity.kt

package com.qrcodekotlin.qrcodekotlin

import android.graphics.Bitmap
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.ImageView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.google.zxing.BarcodeFormat
import com.google.zxing.EncodeHintType
import com.google.zxing.qrcode.QRCodeWriter
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel

class MainActivity : AppCompatActivity() {


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

        // References to UI elements
        val inputEditText: EditText = findViewById(R.id.inputEditText)
        val generateButton: Button = findViewById(R.id.generateButton)
        val qrCodeImageView: ImageView = findViewById(R.id.qrCodeImageView)


        // Set click listener for the button
        generateButton.setOnClickListener {
            val inputData = inputEditText.text.toString()

            if (inputData.isBlank()) {
                // Show a message if input is empty
                Toast.makeText(this, "Please enter text to generate QR code", Toast.LENGTH_SHORT).show()
            } else {
                // Generate QR code
                val bitmap = generateQRCode(inputData)
                // Display QR code
                qrCodeImageView.setImageBitmap(bitmap)
            }
        }

    }

    // Function to generate QR code
    private fun generateQRCode(data: String): Bitmap {
        val writer = QRCodeWriter()
        val hints = hashMapOf<EncodeHintType, Any>()
        hints[EncodeHintType.ERROR_CORRECTION] = ErrorCorrectionLevel.L
        hints[EncodeHintType.MARGIN] = 1

        val bitMatrix = writer.encode(data, BarcodeFormat.QR_CODE, 512, 512, hints)

        // Convert BitMatrix to Bitmap
        val width = bitMatrix.width
        val height = bitMatrix.height
        val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565)

        for (x in 0 until width) {
            for (y in 0 until height) {
                bitmap.setPixel(x, y, if (bitMatrix[x, y]) android.graphics.Color.BLACK else android.graphics.Color.WHITE)
            }
        }

        return bitmap
    }

}