App to generate and scan the QR code.

This is simple APP to generate and scan the QR code.

1. Add below libraries

    implementation 'com.google.zxing:core:3.3.2'
    implementation 'com.journeyapps:zxing-android-embedded:3.6.0@aar'
   

2. Create file an button to call scanNow() function to initiate the Camera for scanning purpose.

    /**this function call the above library to initiate the camera to scan the QRCode**/
   
    private void scanNow() {
    IntentIntegrator integrator = new IntentIntegrator(ScanQRActivity.this);
    integrator.setDesiredBarcodeFormats(IntentIntegrator.QR_CODE);
    integrator.setPrompt("Scanning");
    integrator.setCameraId(0);
    integrator.setBeepEnabled(false);
    integrator.setBarcodeImageEnabled(false);
    integrator.setOrientationLocked(true);
    integrator.setCaptureActivity(CaptureActivityPotrait.class); 
    /**CaptureActivityPotrait.class is java class to customize the scanning layout**/
    integrator.initiateScan();
   

   }

    /**After scanning process Override the **onActivityResult()** function in class to get the result**/
   
     @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
    if (result != null) {
        if (result.getContents() == null) {
            Toast.makeText(this, "You cancelled the scanning", Toast.LENGTH_LONG).show();
        } else {
            QRResult = result.getContents();/**get the scanning result and store in QRResult variable**/
            txtDesc.setText(QRResult);/**set the String result in the textView**/
        }
    } else {
        super.onActivityResult(requestCode, resultCode, data);
    }
   

   }

3. Create file an button to call the generateQRCode() function to start activity.

    /**userInput = get the text **/
   
    private void generateQrCode() {
    MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
    try {
        BitMatrix bitMatrix = multiFormatWriter.encode(userInput, BarcodeFormat.QR_CODE, 200, 200);
        BarcodeEncoder barcodeEncoder = new BarcodeEncoder();
        bitmap = barcodeEncoder.createBitmap(bitMatrix);
        imgQrCode.setImageBitmap(bitmap);/**set the QRCode image in ImageView**/
    } catch (WriterException e) {
        e.printStackTrace();
    }
   

   }

4. Create CaptureActivityPotrait.class and just copy paste all the code.

   public class CaptureActivityPotrait extends Activity {
   private CaptureManager capture;
   private DecoratedBarcodeView barcodeScannerView;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   
   barcodeScannerView = initializeContent();
   
   capture = new CaptureManager(this, barcodeScannerView);
   capture.initializeFromIntent(getIntent(), savedInstanceState);
   capture.decode();
   }
   
   /**
   * Override to use a different layout.
   *
   * @return the DecoratedBarcodeView
   */
    protected DecoratedBarcodeView initializeContent() {
   setContentView(R.layout.activity_qrcode);/**make sure create the XML layout for QR code custom layout**/
   return (DecoratedBarcodeView)findViewById(R.id.zxing_barcode_scanner);
   }
   
   @Override
   protected void onResume() {
   super.onResume();
   capture.onResume();
   }
   
   @Override
   protected void onPause() {
   super.onPause();
   capture.onPause();
   }
   
   @Override
   protected void onDestroy() {
   super.onDestroy();
   capture.onDestroy();
   }
   
   @Override
   protected void onSaveInstanceState(Bundle outState) {
   super.onSaveInstanceState(outState);
   capture.onSaveInstanceState(outState);
   }
   
   @Override
   public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
   capture.onRequestPermissionsResult(requestCode, permissions, grantResults);
   }
   
   @Override
   public boolean onKeyDown(int keyCode, KeyEvent event) {
   return barcodeScannerView.onKeyDown(keyCode, event) || super.onKeyDown(keyCode, event);
   }
   }
   

5. Create activity_qrcode XML layout and jsut copy paste all the code.

     <?xml version="1.0" encoding="UTF-8"?>
   

     <merge xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto">
   
    <!--
    This Activity is typically full-screen. Therefore we can safely use centerCrop scaling with
     a SurfaceView, without fear of weird artifacts. -->
   
    <RelativeLayout
     android:layout_width="match_parent"
    android:layout_height="match_parent">
   
    <com.journeyapps.barcodescanner.DecoratedBarcodeView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/zxing_barcode_scanner"
        app:zxing_preview_scaling_strategy="centerCrop"
        app:zxing_use_texture_view="false"/>
   
    </RelativeLayout>
   
     </merge>
   

1. Main Page layout

2. Scan QR Page layout

3. Generate QR Page layout