Java Question Problem with the onActivityResult

[alwaysbusy]

I'm trying to write a library for the Zxing barcode reader. I can be done by just starting the Zxing intent and you receive de code in a onActivityResult.

It does work to the part that te app is started, de barcode is found and returned. However, the onActivityResult is not called.

The reason is probably simple: de intent is returning the result to the ba Activity, not to the ABBarcode activity.

But a crash occurs when the line

IntentIntegrator.initiateScan(ba.activity);

is changed to

IntentIntegrator.initiateScan(ABBarcode.this);

The error happens on startActivityForResult() in the IntentIntegrator.initiateScan function
Here is the IntentIntegrator.initiateScan function:

public static AlertDialog initiateScan(Activity activity,
                                         CharSequence stringTitle,
                                         CharSequence stringMessage,
                                         CharSequence stringButtonYes,
                                         CharSequence stringButtonNo,
                                         CharSequence stringDesiredBarcodeFormats) {
    Intent intentScan = new Intent("com.google.zxing.client.android.SCAN");
    intentScan.addCategory(Intent.CATEGORY_DEFAULT);
    //intentScan.addFlags(Intent.FLAG_ACTIVITY_FORWARD_RESULT);

    // check which types of codes to scan for
    if (stringDesiredBarcodeFormats != null) {
      // set the desired barcode types
      intentScan.putExtra("SCAN_FORMATS", stringDesiredBarcodeFormats);
    }

    try {
      activity.startActivityForResult(intentScan, REQUEST_CODE);
      return null;
    } catch (ActivityNotFoundException e) {
      return showDownloadDialog(activity, stringTitle, stringMessage, stringButtonYes, stringButtonNo);
    }
  }

And here is the library source code.

package com.AB.ABBarcode;

import android.app.Activity;
import anywheresoftware.b4a.BA;
import anywheresoftware.b4a.BA.ShortName;
import anywheresoftware.b4a.BA.Version;
import anywheresoftware.b4a.BA.Author;
import anywheresoftware.b4a.BA.Events;
import anywheresoftware.b4a.BA.ActivityObject;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;


@ShortName("ABBarcode")
@Events(values={"BarcodeFound (barCode as String)", "Canceled()"})
@Version(1.0f)
@ActivityObject()
@Author("Alain Bailleul")
public class ABBarcode extends Activity {
   private BA _ba=null;
   private String _eventName="";
   
   
   /**
    *Starts the barcode scanner. The barcode is returned in the BarcodeFound event or the Canceled event
    *eventName (String): name of the ABBarcode object
    *mode (String): QR_CODE_MODE for QR barcodes, "ANYTHING" for everything
    *Example:<code>
    *Sub Button1_Click
    *   myABBarcode.ABBarcodeGet("myABBarcode", "QR_CODE_MODE")
    *End Sub
    *
    *Sub myABBarcode_BarcodeFound(barCode as String)
    *   msgbox(barCode, "")
    *End Sub
    *
    *Sub myABBarcode_Canceled
    *   msgbox("Canceled","")
    *End Sub
    *</code>
    */
   public void ABGetBarcode(final BA ba, String eventName, String mode) {
      _ba=ba;
      _eventName=eventName;
      Log.i("ABGetBarcode", "start");
      ABBarcodeFound("start");
      IntentIntegrator.initiateScan(ba.activity);
      //IntentIntegrator.initiateScan(ABBarcode.this);
                  
   }
   
   
   public void onActivityResult(int requestCode, int resultCode, Intent data) {
      Log.i("onActivityResult", "requestcode=" + requestCode + ":resultCode=" + resultCode);
      switch(requestCode) {
         case IntentIntegrator.REQUEST_CODE: { 
            if (resultCode != RESULT_CANCELED) {
               IntentResult scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
               if (scanResult != null) {
                  String upc = scanResult.getContents();
                  ABBarcodeFound(upc);
                 }
            }
            else {
               ABCanceled();               
            }
               
            break;
         }
      }
   }
   
   public void ABBarcodeFound(String barCode){
      Log.i("ABBarcodeFound", barCode);
      final String s = _eventName.toLowerCase(BA.cul) + "_barcodefound";
      Log.i("ABBarcodeFound", s);
      _ba.raiseEvent(this, s, barCode);
   }
   
   public void ABCanceled() {
      Log.i("ABCanceled", "Canceled");
      final String s = _eventName.toLowerCase(BA.cul) + "_canceled";
      Log.i("ABCanceled", s);
      _ba.raiseEvent(this, s);
   }
   
   
}

As always, full source code can be posted if needed.

So close, but no sigar ;-)

Any ideas are welcome

 

[agraham]

I suspect before long you may be able to this within Basic4android without needing library code.

However, for the present, without the full source to play with I can't really try this but I suspect that the problem is that your ABBarcode is not a real Activity to the OS as it is not registered as such in the application manifest so this is why you get a crash. I think you are correct that the result is being returned to the BA activity but can't be intercepted as it has no onActivityResult method.

I think this will need a modification to the Basic4android Activity object and I'm pretty sure this is something Erel has already thought out. Custom Intents arrived this morning in the Phone library so I guess onActivityResult might be in the next release.

 

[alwaysbusy]

thanks for the clarification agraham. I think I'm going to put this project on hold as there is no need to write a workaround if the b4a activity is going to have an onActivityResult event.

It's just I'm having so much fun with b4a and its potential seems endless, especially by the library concept

 

[Erel]

onActivityResult will sure be added in the next update.