Unlock Screen App for Android

Unlock Screen App for Android

I wish to make my own lock screen like this one:
http://www.onlineandroidtips.com/images/o67.jpg
This is what I want to do:
Open app. Set my own Password. Store it somewhere.
Enable/Disable the password lock.
If enabled: When the phone's power button is switched on, my app opens and
asks the user for a password. (phone can also be unlocked by restarting
it)
Emergency calls can be made/taken.
I've visited hundreds of links, and tried KeyguardManager as well as
DeviceManager.
Examples have shown me to: 1. Put phone to sleep 2. Lock the screen 3.
Disable Keys
I want to handle everything, including the password being set, stored, the
xml layout of the lock screen.
I wish to handle locking as well as unlocking the phone.
I don't mind if the phone gets unlocked when the phone is restarted.
(sounds weird, but it's my application's requirement. It will also prevent
any misuse.)
Please help. I'm a beginner. I've only coded very basic apps, which never
required control of the entire device.
I have a nice and new idea for a lock. (i.e. I'm not trying to code it for
the sake of it. My app will be helpful.)
The only feasible option in my mind is to make my own launcher, but I fear
that it will be too tedious.
Is there any simpler way out?