如何在按键上实现上下文菜单而不是长点击

I have a ListActivity and I want to implement context menu for each of the list elements. I know that the common way to do this is to show the context menu on long click/tap. I want to know if there is a way to show the context menu for each element on a key press(preferably the menu key). To rephrase my question, how can I trigger the context menu and not the options menu by pressing the menu key(or any other key). I have a ListActivity and I want to implement c