Android Zxing Embedded Barcodeview Not Resuming

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

Solution 1:

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.
 */publicclassCameraFragmentextendsBaseFragment {
    Context mcontext;
    privateBarcodeView barcodeView;
    final int PERMISSIONS_REQUEST_ACCESS_CAMERA=0;
    View view;


    @OverridepublicViewonCreateView(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(newString[]{Manifest.permission.CAMERA},
                    PERMISSIONS_REQUEST_ACCESS_CAMERA);
        } else {
            barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
            barcodeView.decodeContinuous(callback);

        }


        mcontext=getContext();

        return view;
    }



    @OverridepublicvoidonResume() {

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

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

    privateBarcodeCallback callback = newBarcodeCallback() {
        @OverridepublicvoidbarcodeResult(BarcodeResult result) {
            if (result.getText() != null) {
                barcodeView.pause();
                //after the string has been read we prozess itString 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 againLog.e("RISHABH", "resuming scanner, data needed was not found");
                    barcodeView.resume(); //notice we don't call decodeContinuous function again
                }
            }
        }

        @OverridepublicvoidpossibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @OverridepublicvoidonRequestPermissionsResult(int requestCode, @NonNullString[] 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

Solution 2:

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.

publicclassUtil {
    publicstaticvoidvalidateMainThread() {
        if (Looper.getMainLooper() != Looper.myLooper()) {
            thrownew 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:

publicclassMyInterface {
    Context mContext;
    ActivityMain activityMain;

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

    @JavascriptInterfacepublicvoidresumeScanner() {
        Toast.makeText(mContext, "resume", Toast.LENGTH_SHORT).show();
        HandlermainHandler=newHandler(mContext.getMainLooper());
        RunnablemyRunnable=newRunnable() {
            @Overridepublicvoidrun() {
                activityMain.barcodeView.resume();
            }
        };
        mainHandler.post(myRunnable);
    }
}