findViewById(R.id.imageView_barcode).setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                startZXing();
            }

        });


    private void startZXing() {
        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        int width = size.x;
        int height = size.y;
        Intent intent = new Intent(this, CaptureActivity.class);
        intent.putExtra(Intents.Scan.WIDTH, width);
        intent.putExtra(Intents.Scan.HEIGHT, height);
        intent.putExtra(CaptureActivity.RETURN_RESULT, true);
        intent.setAction(Intents.Scan.ACTION);
        startActivityForResult(intent, 0);
    }