about Launcher android

about Launcher android

I have 2 questions about launcher below:
I have 3-4 launchers on device, how can i know which launcher has been set
default on my device (with code).(Done)
I have own custom launcher app, I want clear default launcher on my app
and without use: Intent uninstallIntent = new
Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, packageURI);
uninstallIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(uninstallIntent); as some app as: Kid's Shell or Kids Place.
I have try follow Clearing and setting the default home application
(SOLVED) but nothing change.
Please show me how to solve 2 things. Thanks for any advise.