If you app is System app then you Simply do this to enable/disable USB Debugging
Settings.Secure.putInt(getActivity().getContentResolver(),Settings.Secure.ADB_ENABLED,
1);
You also need root access to do this.
I have rooted device and I just simply execute SU to enable/disable Usb Debugging.
Process proc = Runtime.getRuntime().exec(new String [] { "su", "-c",
"setprop", "persist.service.adb.enable", "0"});
proc.waitFor();
Process proc2 = Runtime.getRuntime().exec(new String [] { "su", "-c",
"stop", "adbd"});
proc2.waitFor();
Good thing is you don't need to place your application in (/system/priv-app/)
Your simple app i.e. (/data/app) can do this.