Android Question Problems with decoding QRCodeReader v1.02

FernandoGuedes said:

Has this ever happened to anyone?

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FernandoGuedes said:

Hello everybody.

I've successfully used @Johan Schoeman excellent library for a while. But I'm having an unusual problem when trying to decode a QRCode in particular (This one is attached). The reading through the scanner is perfect and brings the information perfectly. But when I try to decode it the result is "null" in the result of the attempt.

Logger conectado a: Xiaomi Redmi Note 8
--------- beginning of main
Copying updated assets files (1)
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
path = /storage/emulated/0/DDCZJG02.jpg
bMap = android.graphics.Bitmap@f6185c7
Decoded = null
** Activity (main) Resume **
** Activity (main) Pause, UserClosed = false **


This is the first time this error occurs and as I'm still a beginner in B4A, I would like to understand a be able to predict and avoid this error.

Has this ever happened to anyone?

Thank you for your attention!

Thanks

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DonManfred said:

How should we know with this less Information/no code shown?

Honestly i did not understand what the problem is actually.

Upload a small project showing the Problem.

Click to expand...

drgottjr said:

nem todos os códigos qr podem ser lidos. há uma série de razões para isso.
no seu caso, eu diria que o exemplo que você postou não tem a área "silenciosa" necessária ao redor do código. pense nisso como uma borda branca ao redor do código.
o "null" relatado pelo leitor significa que não reconheceu a imagem como um código qr. poderia, de fato, ser um código qr produzido incorretamente, mas acho que o problema é o quadro ausente.

se eu lhe der uma bela moldura, não tenho problemas em lê-la.

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delgadol said:

I have use this lib, and works ok in almost the devices; the QR reader fail in some devices; (or it is very .. very slow); devices with focal distance camera over 0.5m; (basic alcatel devices in my case, android moly based devices(cheap asia phone) ); one time i have a very big problem, i try to implements a QR with 244 char info, and it was impossible. the best QR info content is over to 30 char (mixed and ANSI)

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FernandoGuedes said:

Yes @drgottjr , there are many reasons not to be read. The structure of encoding and decoding algorithms for creating and assembling 2D code (QRCode) is quite complex. I use an option in my app (images below) that allows reading the QRCode content of the decoded image. But I understand that the problem is really in the decoding method. I will look for some other more up-to-date image decoding method. I tested the image you sent me with the frame and the result is still "Null". Thank you very much for your effort and attention in helping me to solve this problem

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drgottjr said:

i have no trouble reading your left and right images. export your app and upload it. all the qr code libraries here (even google's mobile vision) are zxing-based. i can read your code with several libraries. as was suggested by @DonManfred, upload your code.

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#Region  Project Attributes
    #ApplicationLabel: b4aDecodeQRcode
    #VersionCode: 1
    #VersionName:
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: portrait
    #CanInstallToExternalStorage: False
#End Region

#AdditionalJar: core-3.2.1

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Dim nativeMe As JavaObject
End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.
   
    Dim decoded As String

    Private Label1 As Label
    Private ImageView1 As ImageView
   
    Dim bm As Bitmap
End Sub

Sub Activity_Create(FirstTime As Boolean)
    'Do not forget to load the layout file created with the visual designer. For example:
    Activity.LoadLayout("main")
   
    nativeMe.InitializeContext
'    bm.Initialize(File.DirRootExternal, "quiet.png")      'QRCode gerado erradamente pelo Lib Clarion
    bm.Initialize(File.DirRootExternal, "e_4_96695.jpg")  'QRCode gerado pelo SimpleCodeGenerator. Resultado: Geração correta !!!
    ImageView1.Bitmap = bm
   
'    texto = 002||||FUPRESA|SALA DE LIMPEZA|5|59358|Extintor|PQS|4 Kg||2023|11/2022|06/2000
'    Dim path As String = File.DirRootExternal & "/quiet.png"      'QRCode gerado erradamente pela Lib Clarion
    Dim path As String = File.DirRootExternal & "/e_4_96695.jpg"      'QRCode gerado pelo SimpleCodeGenerator. Resultado: Geração correta !!!
    decoded = nativeMe.RunMethod("decodeQRImage", Array(path))
    Log("Decoded = " & decoded)
    Label1.Text = decoded
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub



#if Java


import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.NotFoundException;
import com.google.zxing.RGBLuminanceSource;
import com.google.zxing.Reader;
import com.google.zxing.Result;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;

//the inline java code is based on this link:
//https://stackoverflow.com/questions/36210537/find-qr-code-in-image-and-decode-it-using-zxing

public String decodeQRImage(String path) {
    BA.Log("path = " + path);
    Bitmap bMap = BitmapFactory.decodeFile(path);
    BA.Log("bMap = " + bMap);
    String decoded = null;

    int[] intArray = new int[bMap.getWidth() * bMap.getHeight()];
    bMap.getPixels(intArray, 0, bMap.getWidth(), 0, 0, bMap.getWidth(),
            bMap.getHeight());
    LuminanceSource source = new RGBLuminanceSource(bMap.getWidth(),
            bMap.getHeight(), intArray);
    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

    Reader reader = new QRCodeReader();
    try {
        Result result = reader.decode(bitmap);
        decoded = result.getText();
    } catch (NotFoundException e) {
        e.printStackTrace();
    } catch (ChecksumException e) {
        e.printStackTrace();
    } catch (FormatException e) {
        e.printStackTrace();
    }
    return decoded;
}


#End If