Android zxing Embedded BarcodeView not resuming

Question

In my android app I use a Fragment (CameraFragment see below) which uses a BarcodeView. When a Barcode is scanned(BarcodeCallBack) I check if it fits a pattern and if not I want to resume the scanning, but this does not work. The camera keeps running but no Barcode is scanned. As a quickfix I replace the entire Fragment but this is not how it has to be...

The Fragment:

package com.stickydata;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.amazonaws.mobile.AWSMobileClient;
import com.amazonaws.mobilehelper.auth.IdentityManager;
import com.google.zxing.ResultPoint;
import com.journeyapps.barcodescanner.BarcodeCallback;
import com.journeyapps.barcodescanner.BarcodeResult;
import com.journeyapps.barcodescanner.BarcodeView;
import com.stickydata.AWSUtil.SDtagUtil;
import com.stickydata.events.EventResumeBarcodeScan;

import org.greenrobot.eventbus.EventBus;

import java.util.List;

import static com.facebook.FacebookSdk.getApplicationContext;

public class CameraFragment extends Fragment  {
    private IdentityManager identityManager;
Context mcontext;
    private BarcodeView barcodeView;
    final int PERMISSIONS_REQUEST_ACCESS_CAMERA=0;
    View view;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        view=inflater.inflate(R.layout.fragment_camera, container, false);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
                getActivity().checkSelfPermission(Manifest.permission.CAMERA)
                        != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    PERMISSIONS_REQUEST_ACCESS_CAMERA);
        } else {
            barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
            barcodeView.decodeSingle(callback);

        }


        mcontext=getContext();

        return view;
    }



    @Override
    public void onResume() {

        super.onResume();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.resume();
        barcodeView.decodeSingle(callback);

    }

    @Override
    public void onPause() {
        super.onPause();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.pause();
    }


    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            if (result.getText() != null) {
                barcodeView.pause();
                //the vibrator on success
                Vibrator v = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
               // Vibrate for 500 milliseconds
                v.vibrate(200);
               //after the string has been read we prozess it
                String tag_string=result.getText();
                AWSMobileClient.initializeMobileClientIfNecessary(getApplicationContext());
                // Obtain a reference to the mobile client. It is created in the Application class.
                final AWSMobileClient awsMobileClient = AWSMobileClient.defaultMobileClient();

                // Obtain a reference to the identity manager.
                identityManager = awsMobileClient.getIdentityManager();
                SDtagUtil sdTag=new SDtagUtil(tag_string,identityManager,awsMobileClient,mcontext);

                if(!sdTag.prozessTag()){//if the tag was not scanned succesfully let us start the scan again
                    EventBus.getDefault().post(new EventResumeBarcodeScan("bla"));
                    //TODO NOT WORKING
                  //  barcodeView.resume();
                  //  barcodeView.decodeSingle(callback);

                }


            }


        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == PERMISSIONS_REQUEST_ACCESS_CAMERA|| grantResults!=null) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
                barcodeView.decodeContinuous(callback);
            }
        }
    }
}

The fragment xml file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <com.journeyapps.barcodescanner.BarcodeView
        android:id="@+id/barcode_scanner"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:zxing_use_texture_view="true"
    app:zxing_preview_scaling_strategy="fitCenter"/>
</LinearLayout>

Changed to decodeContinous as suggested. The problem remains:

package com.stickydata;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.amazonaws.mobile.AWSMobileClient;
import com.amazonaws.mobilehelper.auth.IdentityManager;
import com.google.zxing.ResultPoint;
import com.journeyapps.barcodescanner.BarcodeCallback;
import com.journeyapps.barcodescanner.BarcodeResult;
import com.journeyapps.barcodescanner.BarcodeView;
import com.stickydata.AWSUtil.SDtagUtil;
import com.stickydata.events.EventResumeBarcodeScan;

import org.greenrobot.eventbus.EventBus;

import java.util.List;

import static com.facebook.FacebookSdk.getApplicationContext;

public class CameraFragment extends Fragment  {
    private IdentityManager identityManager;
Context mcontext;
    private BarcodeView barcodeView;
    final int PERMISSIONS_REQUEST_ACCESS_CAMERA=0;
    View view;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        view=inflater.inflate(R.layout.fragment_camera, container, false);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
                getActivity().checkSelfPermission(Manifest.permission.CAMERA)
                        != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    PERMISSIONS_REQUEST_ACCESS_CAMERA);
        } else {
            barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
            barcodeView.decodeContinuous(callback);

        }


        mcontext=getContext();

        return view;
    }



    @Override
    public void onResume() {

        super.onResume();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.resume();
        barcodeView.decodeContinuous(callback);

    }

    @Override
    public void onPause() {
        super.onPause();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.pause();
    }


    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            if (result.getText() != null) {
                barcodeView.pause();
                //the vibrator on success
                Vibrator v = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
               // Vibrate for 500 milliseconds
                v.vibrate(200);
               //after the string has been read we prozess it
                String tag_string=result.getText();
                AWSMobileClient.initializeMobileClientIfNecessary(getApplicationContext());
                // Obtain a reference to the mobile client. It is created in the Application class.
                final AWSMobileClient awsMobileClient = AWSMobileClient.defaultMobileClient();

                // Obtain a reference to the identity manager.
                identityManager = awsMobileClient.getIdentityManager();
                SDtagUtil sdTag=new SDtagUtil(tag_string,identityManager,awsMobileClient,mcontext);

                if(!sdTag.prozessTag()){//if the tag was not scanned succesfully let us start the scan again
                   // EventBus.getDefault().post(new EventResumeBarcodeScan("bla"));
                    //TODO NOT WORKING
                    barcodeView.resume();
                    barcodeView.decodeContinuous(callback);

                }


            }


        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == PERMISSIONS_REQUEST_ACCESS_CAMERA|| grantResults!=null) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
                barcodeView.decodeContinuous(callback);
            }
        }
    }
}

Rishabh Bhatia · Accepted Answer · 2017-05-15T15:30:17.750

Hi user1406731 you are using the wrong callback, we do something similar in our mobile app. Replace your decodeSingle() callback function with decodeContinuous() callback and it should work. Here is a working example from the official doc Continous Callback example. Hope it helps you.

Hi i tried to run your code & made a little change. This is what i tested and works fine for me

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.google.zxing.ResultPoint;
import com.journeyapps.barcodescanner.BarcodeCallback;
import com.journeyapps.barcodescanner.BarcodeResult;
import com.journeyapps.barcodescanner.BarcodeView;
import com.example.scanner.R;
import com.example.scanner.ui.base.BaseFragment;

import java.util.List;

/**
 * Created by Rishabh Bhatia on 12/5/17.
 */

public class CameraFragment extends BaseFragment {
    Context mcontext;
    private BarcodeView barcodeView;
    final int PERMISSIONS_REQUEST_ACCESS_CAMERA=0;
    View view;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        view=inflater.inflate(R.layout.fragment_camera, container, false);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
                getActivity().checkSelfPermission(Manifest.permission.CAMERA)
                        != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    PERMISSIONS_REQUEST_ACCESS_CAMERA);
        } else {
            barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
            barcodeView.decodeContinuous(callback);

        }


        mcontext=getContext();

        return view;
    }



    @Override
    public void onResume() {

        super.onResume();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.resume();    
    }

    @Override
    public void onPause() {
        super.onPause();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.pause();
    }

    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            if (result.getText() != null) {
                barcodeView.pause();
                //after the string has been read we prozess it
                String tag_string=result.getText();
                Log.e("RISHABH", "pausing scanner, got some data "+tag_string);

                if(!tag_string.equals("abc")){//if the tag was not scanned succesfully let us start the scan again
                    Log.e("RISHABH", "resuming scanner, data needed was not found");
                    barcodeView.resume(); //notice we don't call decodeContinuous function again
                }
            }
        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == PERMISSIONS_REQUEST_ACCESS_CAMERA) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
                barcodeView.decodeContinuous(callback);
            }
        }
    }
}

Here is my logcat

05-12 23:54:13.226 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:13.226 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:18.280 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:18.280 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:19.350 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:19.350 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:20.350 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:20.350 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:21.450 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:21.450 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:22.510 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:22.510 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:33.000 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data abc

Hi Rishabh, thanks for your suggestion but it did not fix the problem. I updated the question with the changed still not working code. — user1406731, May 12 '17 at 16:13
Hi user1406731, i added code that's working for me. Give it a go. — Rishabh Bhatia, May 12 '17 at 18:32
@user1406731 Are u still facing same issue after using the above code? — Rishabh Bhatia, May 15 '17 at 10:28
Dear Rishabh, thank you very much for your help, removing the decodeContinuous after resume() solved it! :) — user1406731, May 15 '17 at 14:26
Welcome @user1406731 Please accept the answer, hopefully it helps others too. — Rishabh Bhatia, May 15 '17 at 15:27

score 1 · Answer 2 · answered Dec 19 '18 at 18:21

I figured it out and thought it might help someone. I had exactly the same issue, then figured out that resume() method do a check if it is running on MainThread.

public class Util {
    public static void validateMainThread() {
        if (Looper.getMainLooper() != Looper.myLooper()) {
            throw new IllegalStateException("Must be called from the main thread.");
        }
    }
}

Here are examples of how to run code on MainThread: Running code in main thread from another thread

I tried to run it from @JavscriptInterface method and here is my code:

public class MyInterface {
    Context mContext;
    ActivityMain activityMain;

    MyInterface(Context c, ActivityMain am) {
        mContext = c;
        activityMain = am;
    }

    @JavascriptInterface
    public void resumeScanner() {
        Toast.makeText(mContext, "resume", Toast.LENGTH_SHORT).show();
        Handler mainHandler = new Handler(mContext.getMainLooper());
        Runnable myRunnable = new Runnable() {
            @Override
            public void run() {
                activityMain.barcodeView.resume();
            }
        };
        mainHandler.post(myRunnable);
    }
}

Android zxing Embedded BarcodeView not resuming

2 Answers2

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