How to scan QRCode in android

Question

I found a tutorial on how to scan a barcode. But in my application I have to scan a QR code. How can I a scan QR code in Android?

Answer 1

My way is to use barcodescanner. I uses zxing for scanning bar codes and QR codes. The version 1.9 of the library utilises zxing v3.2.1. It's a wrapper for zxing so the usage is simplier.

In order to do this:

1. Add dependency to gradle

   compile 'me.dm7.barcodescanner:zxing:1.9'
   

2. Add camera permission to manifest

3. Create activity, that will handle scanning

   Manifest:

   styles.xml:

   Create scanner activity:

   import android.app.Activity;
   import android.content.Intent;
   import android.os.Bundle;
   import android.util.Log;
   import android.view.WindowManager;
   
   import com.google.zxing.BarcodeFormat;
   import com.google.zxing.Result;
   
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.List;
   
   import me.dm7.barcodescanner.zxing.ZXingScannerView;
   
   public class ScannerActivity extends Activity implements ZXingScannerView.ResultHandler {
   
       public static final String EXCLUDED_FORMAT = "ExcludedFormat";
       private static final String TAG = ScannerActivity.class.getSimpleName();
       private ZXingScannerView mScannerView;
   
       @Override
       public void onCreate(Bundle state) {
           setStatusBarTranslucent(true);
           super.onCreate(state);
           mScannerView = new ZXingScannerView(this);
           setContentView(mScannerView);
       }
   
       protected void setStatusBarTranslucent(boolean makeTranslucent) {
           if (makeTranslucent) {
               getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
           } else {
               getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
           }
       }
   
       @Override
       public void onResume() {
           super.onResume();
           mScannerView.setResultHandler(this);
           mScannerView.startCamera();
       }
   
       @Override
       public void onPause() {
           super.onPause();
           mScannerView.stopCamera();
       }
   
       @Override
       public void handleResult(Result rawResult) {
           String result = rawResult.getText();
           BarcodeFormat format = rawResult.getBarcodeFormat();
   
           Log.v(TAG, "Scanned code: " + rawResult.getText());
           Log.v(TAG, "Scanend code type: " + rawResult.getBarcodeFormat().toString());
   
           //Return error
           if (result == null) {
               setResult(RESULT_CANCELED, returnErrorCode(result, format));
               finish();
           }
   
           if (result.isEmpty()) {
               setResult(RESULT_CANCELED, returnErrorCode(result, format));
               finish();
           }
   
           //Return correct code
           setResult(RESULT_OK, returnCorrectCode(result, format));
           finish();
       }
   
       private Intent returnErrorCode(String result, BarcodeFormat format) {
           Intent returnIntent = new Intent();
           returnIntent.putExtra(ScannerConstants.ERROR_INFO, getResources().getString(R.string.scanner_error_message));
           return returnIntent;
       }
   
       private Intent returnCorrectCode(String result, BarcodeFormat format) {
           Intent returnIntent = new Intent();
           returnIntent.putExtra(ScannerConstants.SCAN_RESULT, result);
   
           if (format.equals(BarcodeFormat.QR_CODE)) {
               returnIntent.putExtra(ScannerConstants.SCAN_RESULT_TYPE, ScannerConstants.QR_SCAN);
           } else {
               returnIntent.putExtra(ScannerConstants.SCAN_RESULT_TYPE, ScannerConstants.BAR_SCAN);
           }
   
           return returnIntent;
       }
   
       public void excludeFormats(BarcodeFormat item) {
           Collection defaultFormats = mScannerView.getFormats();
           List formats = new ArrayList<>();
           for (BarcodeFormat format : defaultFormats) {
               if (!format.equals(item)) {
                   formats.add(format);
               }
           }
           mScannerView.setFormats(formats);
       }
   
       public interface ScannerConstants {
           public static final String SCAN_MODES = "SCAN_MODES";
           public static final String SCAN_RESULT = "SCAN_RESULT";
           public static final String SCAN_RESULT_TYPE = "SCAN_RESULT_TYPE";
           public static final String ERROR_INFO = "ERROR_INFO";
           public static final int BAR_SCAN = 0;
           public static final int QR_SCAN = 1;
       }
   }
   

   Just be sure, that on API 23+ devices a permission for camera usage is granted for the application.

   Open the Activity just like the normal one with result expectation:

   Intent intent = new Intent(AddEquipmentActivity.this, ScannerActivity.class);
   startActivityForResult(intent, SCAN_SERIAL_REQUEST);