How to create or generate QR (Quick Response) Code in your Android App? – complete source code

In this video it shows the steps to develop your QR Code generator App in Android Studio. It uses zxing library which is included in the App by adding the dependencies in the build.gradle file (App level) for the ‘com.google.zxing:core:3.2.1’ implementation.

In this tutorial a very simple layout has been designed with one Text Box/ plain text field to enter the string which needs to be converted in the QR Code.

It uses the ImageViewer to display the QR code which is generated in your App in Bitmap format.

We hope you like this video. For any query, suggestions or appreciations we will be glad to hear from you at: programmerworld1990@gmail.com.

Source Code:

package com.example.myqrcodegenerator;

import android.graphics.Bitmap;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import androidx.appcompat.app.AppCompatActivity;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;

public class MainActivity extends AppCompatActivity {
    private EditText editText;
    private ImageView imageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        editText = findViewById(R.id.editText);
        imageView = findViewById(R.id.imageView);
    }

    public void QRCodeButton(View view){
        QRCodeWriter qrCodeWriter = new QRCodeWriter();
        try {
            BitMatrix bitMatrix = qrCodeWriter.encode(editText.getText().toString(), BarcodeFormat.QR_CODE, 200, 200);
            Bitmap bitmap = Bitmap.createBitmap(200, 200, Bitmap.Config.RGB_565);
            for (int x = 0; x<200; x++){
                for (int y=0; y<200; y++){
                    bitmap.setPixel(x,y,bitMatrix.get(x,y)? Color.BLACK : Color.WHITE);
                }
            }
            imageView.setImageBitmap(bitmap);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

<?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:layout_marginStart="150dp"
        android:layout_marginTop="83dp"
        android:onClick="QRCodeButton"
        android:text="@string/qr_code"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="85dp"
        android:layout_marginTop="52dp"
        android:ems="10"
        android:hint="@string/enter_the_text_here"
        android:inputType="textPersonName"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button"
        android:autofillHints="" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_marginStart="105dp"
        android:layout_marginTop="85dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        app:srcCompat="?attr/actionBarDivider"
        android:contentDescription="@string/todo" />
</androidx.constraintlayout.widget.ConstraintLayout>

apply plugin: 'com.android.application'

android {
    compileSdkVersion 29
    defaultConfig {
        applicationId "com.example.myqrcodegenerator"
        minSdkVersion 28
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'

    implementation 'com.google.zxing:core:3.2.1'
}

Screenshots of the QR Scanner (used on real phone):

Enter the String “Hello World” Which will be scanned and shown by your QR reader:

Enter any website address, Example: https://programmerworld.co and it will give you an option to browse to that website directly.