QR Code Scanner – Barcode Scanner for Android

Filed Under: Android

QR Code scanner or Barcode scanner for android features are present in many apps to read some useful data. In this tutorial, we’ll be discussing and implementing the Barcode API present in the Google Mobile Vision API. To know the implementation of Face Detection using the Vision API refer here.

Barcode Scanner for Android

QR Code Scanner for Android, Bar code scanner for android tutorial
With the introduction of Google Vision API, implementing Barcodes in an application has got a lot easier for developers.

Following are the major formats that the Vision API supports.

  • 1D barcodes: EAN-13, EAN-8, UPC-A, UPC-E, Code-39, Code-93, Code-128, ITF, Codabar
  • 2D barcodes: QR Code, Data Matrix, PDF-417, AZTEC

Barcodes can scan things ranging from URL, Contact info to Geolocation, WIFI, Driver license IDs.

QR Code is the more popular format and is commonly seen in many applications.

Below, we’ll be developing an application that scans the QR Code value from a bitmap image as well as detects QR Code through a camera and perform the relevant actions.

QR Code Scanner for Android project structure

QR Code Scanner for Android, Barcode scanner for anroid

Configuring Android Studio for Barcode Library

Add the following inside the build.gradle file.


implementation 'com.google.android.gms:play-services-vision:11.8.0'

Add the following inside the AndroidManifest.xml file application tag to enable barcode detection in your application.


<meta-data
            android:name="com.google.android.gms.vision.DEPENDENCIES"
            android:value="barcode" />

QR Code Scanner from Image

The code for the activity_main.xml layout file is given below.


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">


    <Button
        android:id="@+id/btnTakePicture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="@string/take_barcode_picture" />

    <Button
        android:id="@+id/btnScanBarcode"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/btnTakePicture"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="@dimen/activity_horizontal_margin"
        android:text="@string/scan_barcode" />
</RelativeLayout>

The code for the MainActivity.java is given below.


package com.journaldev.barcodevisionapi;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    Button btnTakePicture, btnScanBarcode;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initViews();
    }

    private void initViews() {
        btnTakePicture = findViewById(R.id.btnTakePicture);
        btnScanBarcode = findViewById(R.id.btnScanBarcode);
        btnTakePicture.setOnClickListener(this);
        btnScanBarcode.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.btnTakePicture:
                startActivity(new Intent(MainActivity.this, PictureBarcodeActivity.class));
                break;
            case R.id.btnScanBarcode:
                startActivity(new Intent(MainActivity.this, ScannedBarcodeActivity.class));
                break;
        }

    }
}

The MainActivity.java contains two buttons. The first launches an Activity that scans for a QR Code in the bitmap image captured from the camera and returns the data present in the QR Code(if any). The second scans for the QRCode and detects them in real time.

Before we move onto the business logic of the application, we need to add the following permissions to the AndroidManifest.xml file.


<uses-feature
        android:name="android.hardware.camera"
        android:required="true" />

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera.autofocus" />

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.INTERNET" />

To share and access the files created by other applications we need to add the following provider tag inside our application tag in the AndroidManifest.xml file.


<provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="${applicationId}.provider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/provider_paths" />
        </provider>

This is required for retrieving the image captured by the camera in our QR code scanner for android application.

Let’s start with the first one namely the PictureBarcodeActivity.java.

The code for the xml layout activity_barcode_picture.xml is given below.


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:layout_centerHorizontal="true"
        android:src="@mipmap/journaldev_logo" />

    <TextView
        android:id="@+id/txtResultsHeader"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/imageView"
        android:layout_centerHorizontal="true"
        android:text="Results"
        android:textSize="18sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/txtResultsBody"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/txtResultsHeader"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="@dimen/activity_horizontal_margin"
        android:gravity="center" />

    <Button
        android:id="@+id/btnOpenCamera"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="@dimen/activity_horizontal_margin"
        android:layout_marginTop="@dimen/activity_horizontal_margin"
        android:text="@string/open_camera" />
</RelativeLayout>

The code for the PictureCodeActivity.java class is given below.


package com.journaldev.barcodevisionapi;

import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.util.SparseArray;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.vision.Frame;
import com.google.android.gms.vision.barcode.Barcode;
import com.google.android.gms.vision.barcode.BarcodeDetector;

import java.io.File;
import java.io.FileNotFoundException;

public class PictureBarcodeActivity extends AppCompatActivity implements View.OnClickListener {

    Button btnOpenCamera;
    TextView txtResultBody;

    private BarcodeDetector detector;
    private Uri imageUri;
    private static final int REQUEST_CAMERA_PERMISSION = 200;
    private static final int CAMERA_REQUEST = 101;
    private static final String TAG = "API123";
    private static final String SAVED_INSTANCE_URI = "uri";
    private static final String SAVED_INSTANCE_RESULT = "result";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_barcode_picture);

        initViews();

        if (savedInstanceState != null) {
            if (imageUri != null) {
                imageUri = Uri.parse(savedInstanceState.getString(SAVED_INSTANCE_URI));
                txtResultBody.setText(savedInstanceState.getString(SAVED_INSTANCE_RESULT));
            }
        }

        detector = new BarcodeDetector.Builder(getApplicationContext())
                .setBarcodeFormats(Barcode.DATA_MATRIX | Barcode.QR_CODE)
                .build();

        if (!detector.isOperational()) {
            txtResultBody.setText("Detector initialisation failed");
            return;
        }
    }

    private void initViews() {
        txtResultBody = findViewById(R.id.txtResultsBody);
        btnOpenCamera = findViewById(R.id.btnTakePicture);
        txtResultBody = findViewById(R.id.txtResultsBody);
        btnOpenCamera.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.btnTakePicture:
                ActivityCompat.requestPermissions(PictureBarcodeActivity.this, new
                        String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
                break;
        }

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case REQUEST_CAMERA_PERMISSION:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
                    takeBarcodePicture();
                } else {
                    Toast.makeText(getApplicationContext(), "Permission Denied!", Toast.LENGTH_SHORT).show();
                }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == CAMERA_REQUEST && resultCode == RESULT_OK) {
            launchMediaScanIntent();
            try {


                Bitmap bitmap = decodeBitmapUri(this, imageUri);
                if (detector.isOperational() && bitmap != null) {
                    Frame frame = new Frame.Builder().setBitmap(bitmap).build();
                    SparseArray<Barcode> barcodes = detector.detect(frame);
                    for (int index = 0; index < barcodes.size(); index++) {
                        Barcode code = barcodes.valueAt(index);
                        txtResultBody.setText(txtResultBody.getText() + "\n" + code.displayValue + "\n");

                        int type = barcodes.valueAt(index).valueFormat;
                        switch (type) {
                            case Barcode.CONTACT_INFO:
                                Log.i(TAG, code.contactInfo.title);
                                break;
                            case Barcode.EMAIL:
                                Log.i(TAG, code.displayValue);
                                break;
                            case Barcode.ISBN:
                                Log.i(TAG, code.rawValue);
                                break;
                            case Barcode.PHONE:
                                Log.i(TAG, code.phone.number);
                                break;
                            case Barcode.PRODUCT:
                                Log.i(TAG, code.rawValue);
                                break;
                            case Barcode.SMS:
                                Log.i(TAG, code.sms.message);
                                break;
                            case Barcode.TEXT:
                                Log.i(TAG, code.displayValue);
                                break;
                            case Barcode.URL:
                                Log.i(TAG, "url: " + code.displayValue);
                                break;
                            case Barcode.WIFI:
                                Log.i(TAG, code.wifi.ssid);
                                break;
                            case Barcode.GEO:
                                Log.i(TAG, code.geoPoint.lat + ":" + code.geoPoint.lng);
                                break;
                            case Barcode.CALENDAR_EVENT:
                                Log.i(TAG, code.calendarEvent.description);
                                break;
                            case Barcode.DRIVER_LICENSE:
                                Log.i(TAG, code.driverLicense.licenseNumber);
                                break;
                            default:
                                Log.i(TAG, code.rawValue);
                                break;
                        }
                    }
                    if (barcodes.size() == 0) {
                        txtResultBody.setText("No barcode could be detected. Please try again.");
                    }
                } else {
                    txtResultBody.setText("Detector initialisation failed");
                }
            } catch (Exception e) {
                Toast.makeText(getApplicationContext(), "Failed to load Image", Toast.LENGTH_SHORT)
                        .show();
                Log.e(TAG, e.toString());
            }
        }
    }

    private void takeBarcodePicture() {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        File photo = new File(Environment.getExternalStorageDirectory(), "pic.jpg");
        imageUri = FileProvider.getUriForFile(PictureBarcodeActivity.this,
                BuildConfig.APPLICATION_ID + ".provider", photo);
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        startActivityForResult(intent, CAMERA_REQUEST);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        if (imageUri != null) {
            outState.putString(SAVED_INSTANCE_URI, imageUri.toString());
            outState.putString(SAVED_INSTANCE_RESULT, txtResultBody.getText().toString());
        }
        super.onSaveInstanceState(outState);
    }

    private void launchMediaScanIntent() {
        Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        mediaScanIntent.setData(imageUri);
        this.sendBroadcast(mediaScanIntent);
    }

    private Bitmap decodeBitmapUri(Context ctx, Uri uri) throws FileNotFoundException {
        int targetW = 600;
        int targetH = 600;
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        bmOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(ctx.getContentResolver().openInputStream(uri), null, bmOptions);
        int photoW = bmOptions.outWidth;
        int photoH = bmOptions.outHeight;

        int scaleFactor = Math.min(photoW / targetW, photoH / targetH);
        bmOptions.inJustDecodeBounds = false;
        bmOptions.inSampleSize = scaleFactor;

        return BitmapFactory.decodeStream(ctx.getContentResolver()
                .openInputStream(uri), null, bmOptions);
    }
}

Few inferences drawn from the above code are given below.

  • The following code creates a Barcode Detector.
    
    detector = new BarcodeDetector.Builder(getApplicationContext())
               .setBarcodeFormats(Barcode.DATA_MATRIX | Barcode.QR_CODE)
               .build();
    
  • The types of formats to be scanned are set inside the method setBarcodeFormats().
  • takeBarcodePicture() function is where the camera is launched. To retrieve the image we use the launchMediaScanIntent() that calls a broadcast Intent to search for the image using the image URI.
  • A Frame.Builder is used to create a frame of the Bitmap image. Over the frame, the Barcode detector scans for the possible QR Codes.
    The following line in the above code creates a Frame out of the Bitmap.

    
    Frame frame = new Frame.Builder().setBitmap(bitmap).build();
    
  • We’ve created a SparseArray that’ll contain all possible QR Codes present in the image by invoking the detect() method over the Barcode Detector.

    
    SparseArray<Barcode> barcodes = detector.detect(frame);
    

    To get the format of the QR Code, the valueFormat field is called over the Barcode instance as shown below.

    
    barcodes.valueAt(index).valueFormat
    
  • To get the displayed value and the raw values, the following are invoked.

    
    barcodes.valueAt(index).displayValue
    barcodes.valueAt(index).rawValue
    
  • The relevant value returned is displayed in the TextView. For then one Barcodes in a Bitmap, their values are appended to the current TextView.

The ScannedBarcodeActivity.java class scans for the Barcode through the camera. We’ve generated two of our own custom QR Codes from here.
The code for the layout of the activity_scan_barcode.xml is given below.


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="@dimen/activity_horizontal_margin">

    <SurfaceView
        android:id="@+id/surfaceView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/btnAction"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_centerVertical="true" />

    <TextView
        android:id="@+id/txtBarcodeValue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:layout_marginStart="@dimen/activity_horizontal_margin"
        android:text="No Barcode Detected"
        android:textColor="@android:color/white"
        android:textSize="20sp" />


    <Button
        android:id="@+id/btnAction"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:text="ADD CONTENT IN THE MAIL" />

</RelativeLayout>

Barcode Scanner for Android from Camera

The code for the ScannedBarcodeActivity.java is given below.


package com.journaldev.barcodevisionapi;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.SparseArray;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.vision.CameraSource;
import com.google.android.gms.vision.Detector;
import com.google.android.gms.vision.barcode.Barcode;
import com.google.android.gms.vision.barcode.BarcodeDetector;

import java.io.IOException;

public class ScannedBarcodeActivity extends AppCompatActivity {

    SurfaceView surfaceView;
    TextView txtBarcodeValue;
    private BarcodeDetector barcodeDetector;
    private CameraSource cameraSource;
    private static final int REQUEST_CAMERA_PERMISSION = 201;
    Button btnAction;
    String intentData = "";
    boolean isEmail = false;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan_barcode);

        initViews();
    }

    private void initViews() {
        txtBarcodeValue = findViewById(R.id.txtBarcodeValue);
        surfaceView = findViewById(R.id.surfaceView);
        btnAction = findViewById(R.id.btnAction);


        btnAction.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (intentData.length() > 0) {
                    if (isEmail)
                        startActivity(new Intent(ScannedBarcodeActivity.this, EmailActivity.class).putExtra("email_address", intentData));
                    else {
                        startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(intentData)));
                    }
                }


            }
        });
    }

    private void initialiseDetectorsAndSources() {

        Toast.makeText(getApplicationContext(), "Barcode scanner started", Toast.LENGTH_SHORT).show();

        barcodeDetector = new BarcodeDetector.Builder(this)
                .setBarcodeFormats(Barcode.ALL_FORMATS)
                .build();

        cameraSource = new CameraSource.Builder(this, barcodeDetector)
                .setRequestedPreviewSize(1920, 1080)
                .setAutoFocusEnabled(true) //you should add this feature
                .build();

        surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder holder) {
                try {
                    if (ActivityCompat.checkSelfPermission(ScannedBarcodeActivity.this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
                        cameraSource.start(surfaceView.getHolder());
                    } else {
                        ActivityCompat.requestPermissions(ScannedBarcodeActivity.this, new
                                String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
                    }

                } catch (IOException e) {
                    e.printStackTrace();
                }


            }

            @Override
            public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            }

            @Override
            public void surfaceDestroyed(SurfaceHolder holder) {
                cameraSource.stop();
            }
        });


        barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
            @Override
            public void release() {
                Toast.makeText(getApplicationContext(), "To prevent memory leaks barcode scanner has been stopped", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void receiveDetections(Detector.Detections<Barcode> detections) {
                final SparseArray<Barcode> barcodes = detections.getDetectedItems();
                if (barcodes.size() != 0) {


                    txtBarcodeValue.post(new Runnable() {

                        @Override
                        public void run() {

                            if (barcodes.valueAt(0).email != null) {
                                txtBarcodeValue.removeCallbacks(null);
                                intentData = barcodes.valueAt(0).email.address;
                                txtBarcodeValue.setText(intentData);
                                isEmail = true;
                                btnAction.setText("ADD CONTENT TO THE MAIL");
                            } else {
                                isEmail = false;
                                btnAction.setText("LAUNCH URL");
                                intentData = barcodes.valueAt(0).displayValue;
                                txtBarcodeValue.setText(intentData);

                            }
                        }
                    });

                }
            }
        });
    }


    @Override
    protected void onPause() {
        super.onPause();
        cameraSource.release();
    }

    @Override
    protected void onResume() {
        super.onResume();
        initialiseDetectorsAndSources();
    }
}

Few inferences drawn from the above code are given below.

  • SurfaceView is good to display camera preview images as it renders the GUI rapidly.
    The interface SurfaceHolder.Callback is used to receive information about changes that occur in the surface (in this case, the camera preview). SurfaceHolder.Callback implements three methods:

    • SurfaceChanged : This method is called when the size or the format of the surface changes.
    • SurfaceCreated : When, in the first instance, the surface is created, this method is called.
    • SurfaceDestroyed : This is called when the surface is destroyed.
  • CameraSource manages the camera in conjunction with an underlying detector.
    Here SurfaceView is the underlying detector.
    CameraSource.start() opens the camera and starts sending preview frames to the SurfaceView.
    CameraSource is created in the following way:

    
    cameraSource = new CameraSource.Builder(this, barcodeDetector)
                    .setRequestedPreviewSize(1920, 1080)
                    .setAutoFocusEnabled(true) //you should add this feature
                    .build();
    
  • We’ve assigned a processor on the Barcode Detector using setProcessor().
    The interface contains the callback to the method receiveDetections() which receives the QR Code from the camera preview and adds them in the SparseArray.
  • The value of the QR Code is displayed in the TextView using a Runnable since the Barcodes are detected in a background thread.
  • In this example, we’ve created two barcodes using the generator. One contains the URL. The second contains an email address.
    On clicking the button, based on the QR code value detected, we’ll either launch the URL or send an email to the relevant email address detected from the QR Code.

The output of the PictureBarcodeActivity.java is given below.

bar code scanner for android app

The output of the ScannedBarcodeActivity.java activity in action is given below.

QR Code scanner for android

That’s all for QR code scanner project for android using Mobile Vision API. We’ve added the sample QR Codes to the source code. You can download the final Android QR Code Scanner/Barcode Scanner Project from the link below and play around with different QR Codes.

Comments

  1. ishan says:

    can u create a tutorial to integrate firebase database into this barcode scanning app

  2. Mohammad Hamayel says:

    Thanks a lot. It was very helpful to me — just download the source code and it will run perfectly.

  3. dharmendra sharma says:

    hello sir

    I want to set camera zoom in the scanner. i have tried it with the camera api but it is now deprecated

  4. Nitesh singh says:

    thank you sir

  5. Oren says:

    Hai,

    How do you make the barcode scan not automatic? I mean maybe by using a button on ScannedBarcodeActivity each will do a barcode scanning.

  6. Bryan Zadali says:

    How to catch barcode format to string value ?

  7. 080dev says:

    SparseArray barcodes = detections.getDetectedItems()
    QRcode is not getting scanned and Not getting any result in barcodes.

  8. Kinjal sakhiya says:

    on resume method called multiple times please give solution

  9. Mujahideen says:

    Easy Step by Step Instruction, Thanks

  10. ajmal says:

    Hi, How to zoom the camera.

  11. Reyhane.F says:

    Hi everybody, Thanks a lot Anupam Chugh for your nice tutorial.
    I have a problem in first section, when I run app and take picture from a QR code, always receive this message: “No barcode could be detected. Please try again.” ,even I tried multiple times and set the barcode picture over my phone screen edges, but problem was the same. What’s problem? why this problem happens?
    (P.S: maybe useful – My phone android OS is 4.4.4 and has no high quality camera ( HTC Desire 820), but it works good by other barcode scanner apps).
    Thanks for any help and sorry for my poor English!

  12. Yazan says:

    Hi brather …

    I have this problem, please help me


    Error:Could not resolve all files for configuration ‘:app:debugCompileClasspath’.
    > Could not resolve com.google.android.gms:play-services-vision:11.8.0.
    Required by:
    project :app
    > No cached version of com.google.android.gms:play-services-vision:11.8.0 available for offline mode.
    > No cached version of com.google.android.gms:play-services-vision:11.8.0 available for offline mode. ”

  13. ricardo silveira says:

    EmailActivity.class??? at Scannedbarcode.java does match to any class mentioned by you?Please let me know if I am wrong. thanks

  14. Vaibhav says:

    How can we grab/surround just the barcode, just like Paytm?

  15. asm says:

    No resource found that matches the given name (at ‘resource’ with value ‘@xml/provider_paths’).
    error

    1. Suraj says:

      Where is ‘@xml/provider_paths’ code?

    2. Rally says:

      to get the missing resource either get the code below and copy the provider_paths.cml from res/xml or create a new xml folder in res folder and create provider_paths.xml file. Put this code inside

      At least that worked for me.

  16. Guillaume says:

    It is definitely the best and easiest tutorial. I saved a lot of time. THANKS

  17. alex says:

    XML files missing @dimen definitions.

    1. Alex.S says:

      this has to made using sdk 26

      1. fruitjam says:

        The minimum SDK can be 23.

    2. Hiroshi Kobayashi says:

      You need to put the dimens.xml in the res/values folder.

  18. Muhammad Ja'afar says:

    The best and easiest tutorial on android bar codes i have come across. Thanks man.

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