android application runs in background

Not sure if possible, but is there a way to have an application runni开发者_如何转开发ng in the background and that will work with other applications? For example - can I have an application that add gesture shortcuts (for example for paste) and it will work with ANY application I run? Kind of a service running in the background.

Yes, there is excatly that kind of thing. And it's called... Service

There are many good tutorials out there on this topic, like this one.

Also you might want to check the Android resources on Gestures.