Generate QR Code by ZXing in Android

BarcodeEncoder.kt

import android.graphics.Bitmap
import com.google.zxing.BarcodeFormat
import com.google.zxing.EncodeHintType
import com.google.zxing.MultiFormatWriter
import com.google.zxing.common.BitMatrix
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel


object BarcodeEncoder {

    fun createBitmap(
        matrix: BitMatrix,
        bgColor: Int = 0xFFFFFFFF.toInt(),
        fgColor: Int = 0xFF000000.toInt(),
    ): Bitmap {
        val width = matrix.width
        val height = matrix.height
        val pixels = IntArray(width * height)
        for (y in 0 until height) {
            val offset = y * width
            for (x in 0 until width) {
                pixels[offset + x] = if (matrix.get(x, y)) fgColor else bgColor
            }
        }
        val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
        bitmap.setPixels(pixels, 0, width, 0, 0, width, height)
        return bitmap
    }

    fun encode(
        contents: String,
        format: BarcodeFormat,
        width: Int,
        height: Int = width,
        hints: Map<EncodeHintType, Any>? = null,
    ): BitMatrix {
        return MultiFormatWriter().encode(contents, format, width, height, hints)
    }

    fun encodeQrcode(
        contents: String,
        width: Int,
        height: Int = width,
        errorCorrection: ErrorCorrectionLevel? = null, // default is Low
        margin: Int? = null // default is 4
    ): BitMatrix {
        return encode(
            contents,
            BarcodeFormat.QR_CODE,
            width,
            height,
            buildMap {
                if (errorCorrection != null) put(EncodeHintType.ERROR_CORRECTION, errorCorrection)
                if (margin != null) put(EncodeHintType.MARGIN, margin)
            }
        )
    }

    fun encodeAsBitmap(
        contents: String,
        format: BarcodeFormat,
        width: Int,
        height: Int = width,
        hints: Map<EncodeHintType, Any>? = null,
        bgColor: Int = 0xFFFFFFFF.toInt(),
        fgColor: Int = 0xFF000000.toInt(),
    ): Bitmap {
        return createBitmap(encode(contents, format, width, height, hints), bgColor, fgColor)
    }

    fun encodeQrcodeAsBitmap(
        contents: String,
        width: Int,
        height: Int = width,
        errorCorrection: ErrorCorrectionLevel? = null,
        margin: Int? = null,
        bgColor: Int = 0xFFFFFFFF.toInt(),
        fgColor: Int = 0xFF000000.toInt(),
    ): Bitmap {
        return createBitmap(
            encodeQrcode(contents, width, height, errorCorrection, margin), bgColor, fgColor
        )
    }
}

build.gradle

dependencies {
    implementation "com.google.zxing:core:3.4.1"
}