Using ZXing in Activity with Fragment does not work

Question

In my App I have a MainActivity, which makes use of different fragments. One of these fragments is kind of a detail fragment, where I want to capture some serials by scanning a QR code. Currently, I am trying to use the IntentIntegrator. I am able to scan the code successfully, but after that, my App is not returning correctly. It just displays my MainActivity, but there is no Toast.

I also tried to put a onActivityResult() in the fragment and a super.onActivityResult()in the activities onActivityResult() but it is always the same behaviour. It just jumps into the MainActivity and nothing futher happens.

Can somebody exlain to me, where I made the mistakes? I want to scan the barcode and get the results in my fragment class.

Here is my MainActivity Code:

public class MainActivity extends Activity {
    private Button startenButton, ansehenButton, abmeldenButton;
    private FrameLayout fragmentFrame;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        fragmentFrame = (FrameLayout) findViewById(R.id.frameLayout);

        startenButton = (Button) findViewById(R.id.buttonPruefungStart);
        startenButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                FragmentTransaction transaction = getFragmentManager().beginTransaction();
                if (fragmentFrame.getChildCount() < 1) {
                    transaction.add(R.id.frameLayout, new PruefungStartenFragment());
                } else {
                    transaction.replace(R.id.frameLayout, new PruefungStartenFragment());
                }
                transaction.commit();
            }
        });
    }

    public void scan() {
         IntentIntegrator integrator = new IntentIntegrator(this);
         integrator.initiateScan();
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        IntentResult scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
        if (scanResult != null) {
            Toast.makeText(this, scanResult.getContents(), Toast.LENGTH_LONG).show();
        }
    }

}

And here is my PruefungStartenFragment Code:

public class PruefungStartenFragment extends Fragment {

    private TextView datum, ort, pruefer, bedienerdisplay, scanner, fingerprintscanner, quittungsdrucker, barcodeleser,
            webcam, kundendisplay, terminal;
    private Button scanButton, startButton;

    public static PruefungStartenFragment newInstance(String code) {
        Bundle args = new Bundle();
        args.putSerializable("code", code);

        PruefungStartenFragment fragment = new PruefungStartenFragment();
        fragment.setArguments(args);

        return fragment;
    }

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

        View v = inflater.inflate(R.layout.pruefung_starten_fragment, container, false);
        scanButton = (Button) v.findViewById(R.id.buttonScan);
        scanButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                ((MainActivity)getActivity()).scan();
            }
        });



        return v;
    }



}

Answer 1

I figured out my problem... In my manifest I had a android:noHistory="true" in my MainActivity. This prevents the scanning activity in the barcode scanner to pass the result to my MainActivity, because there is no activity on the stack, where it could pass results to.