How to create a "stealth"-like Android app?

I'd like to have my application run in somewhat of a "stealth" mode. Two main things I'd like to do:

1. Not show app icon in installed app list (drawer?) programmatically.
2. Launch app via dial pad (some special number combination)

I know I can remove the launcher intent filter to hide the icon:

<category android:name="android.intent.category.LAUNCHER" />

But I'd like to do this programmatically, based on app settings. I guess I could work around that, b开发者_JS百科ut the biggest issue for me is figuring out how to launch the app via dial pad. I've googled around and searched SO, but haven't really found anything to help with that.

Thanks in advance.

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• You can programmatically remove icon from launcher as described here
• If you want to launch app as call to magic number, it's quite simple using BroadcastReceivers for outgoing call, you can get solution from Right Number app