The key in my Eclipse(ADT linux):
'Name': 'Show Tooltip Description'
'Description': 'Displays information for the current caret location in a focused hover'
'Binding' : 'F2'
You can use Ctrl + Q to show the quick javadoc of current caret location.
If you want it on hover go to
File > Settings > Editor
and tick the checkbox "Show quick doc on mouse move". You can also set the time delay after hover to make sure just moving cursor in editor doesn't show the javadocs.
As per comments
Alt + Enter can be used for Quick Fixes in Android Studio, It will give you drop down for possible fixes same like in Eclipse.