Zxing Libarary for Android Studio Usage

Just Import to Your project.

Intent intent = new Intent("com.google.zxing.client.android.SCAN");

intent.putExtra("SCAN_MODE", "SCAN_MODE");

startActivityForResult(intent, QRCODE_REQUEST);

Result:

@Override

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);
    if (requestCode == QRCODE_REQUEST) {
        if (resultCode == RESULT_OK) {
            String contents = intent.getStringExtra("SCAN_RESULT");
            Log.e("contents", contents);
        } else if (resultCode == RESULT_CANCELED) {
        }

    }
}