Brother SDK Calling PrintImage causes JNI DETECTED ERROR IN APPLICATION: GetStringUTFChars received NULL jstring

Question

Currently working with the Brother SDK for a label Printer and when I call Asset Manager, the Bitmap appears but when it is parsed to print image it crashes.

if (myPrinter.startCommunication()) {
AssetManager assetManager = getAssets();
          Bitmap bitmap = null;
          try{
              bitmap = BitmapFactory.decodeStream(new BufferedInputStream(assetManager.open("meme.bmp")));
             }catch(Exception e){
               e.printStackTrace();
             }
          PrinterStatus result = myPrinter.printImage(bitmap);
       if (result.errorCode != ErrorCode.ERROR_NONE) {
         Log.d("TAG", "ERROR - " + result.errorCode);
       }
         myPrinter.endCommunication();
}

Stack Readout

Debugger printout, with Image Preview.

Answer 1

For anyone got stuck even if they made sure they have the write permission granted, it was about the working path b-PAC trying to create.

The default path is: /storage/emulated/0/com.brother.ptouch.sdk/template

Just define your own path in PrinterInfo object. Set the workPath variable as such:

PrinterInfo mPrintSettings = mPrinter.getPrinterInfo();
mPrintSettings.workPath = "your/custom/work/path";

It says in the document that you don't even need the permission if you do so. But I'm going to keep it anyway.

Answer 2

I had this issue as well. Have you made sure that the android.permission.WRITE_EXTERNAL_STORAGE permisson is granted. Having this in the manifest file wasn't enough, but by requesting permisson from the user, this specific error went away.

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