I have been looking for an app to lock the screen of my HTC Desire HD. I tried a few screen locking apps for my HTC Desire HD. Everything worked, but after locking my screen, the screen turns off and lights up again with the locked screen displayed. It stays back lit for 15 seconds than finally goes off. So while they work, they do not duplicate the way the power button on the DHD locks and turns the screen of immediately.
I came across an app called Screen Off and Lock. This app has an option to "Delay device locking". This option prevents the screen from coming back on immediately. It works exactly like the power button on my DHD. Brilliant.
It gives you the option to lock with a icon, or using a long press of a search key. For those who want to add a bit of flair it even allows you to select different lock screen animations and sounds if you like. The developer also included a lot of documentation to prevent you from having problems in case you decide to uninstall it. And actually, even this unnecessary since they provide a one click button instead of having to:
Before uninstalling, go to "Settings" > "Location & Security" > "Select device admin" and uncheck "[name of lock screen app]"
All apps should be this way. Feature filled, well documented, with a explanation near each selection option to guide you. Amazingly it is free. You have the option to donate... this really should be a paid app, so please do donate.
Link to the app at the Android Market: Screen Off and Lock