To show a dialog, you need to:

1. Add an extra key EXTRA_ALERT_DIALOG with value ALERT_DIALOG_SHOW.
2. Add an extra title with key EXTRA_ALERT_DIALOG_MESSAGE.
3. The default timeout for the alert display is 5 seconds. If you need to change it, set EXTRA_ALERT_DIALOG_SHOW_TIME as an integer in milliseconds.

Java

myIntent.putExtra(DocumentScannerActivity.EXTRA_ALERT_DIALOG, DocumentScannerActivity.ALERT_DIALOG_SHOW);
myIntent.putExtra(DocumentScannerActivity.EXTRA_ALERT_DIALOG_MESSAGE, "Loren Ipsum");
myIntent.putExtra(DocumentScannerActivity.EXTRA_ALERT_DIALOG_SHOW_TIME, 5000); 

The overlay can be overridden if Stream Actions are received to show messages.