a simply way. redirect to the playstore to install if havent the scanner
try {
intentscan = new Intent(
"com.google.zxing.client.android.SCAN");
startActivityForResult(intentscan, 0);
} catch (ActivityNotFoundException ex) {
new AlertDialog.Builder(MainActivity.this)
.setIcon(R.drawable.ic_launcher)
.setTitle("You must install\nBarcode Scanner\nof Zxing")
.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,int which) {
Intent i = new Intent(
Intent.ACTION_VIEW,
Uri.parse("https://play.google.com/store/apps/details?id=com.google.zxing.client.android"));
startActivity(i);
finish();
}
}).show();
}