8.9 Quick Documentation Lookup
Context sensitive Java and Android documentation can be accessed by placing the cursor over the declaration for which documentation is required and pressing the Ctrl-Q keyboard shortcut (Ctrl-J on macOS). This will display a popup containing the relevant reference documentation for the item. Figure 8-17, for example, shows the documentation for the Android Snackbar class.
Once displayed, the documentation popup can be moved around the screen as needed. Clicking on the push pin icon located in the right-hand corner of the popup title bar will ensure that the popup remains visible once focus moves back to the editor, leaving the documentation visible as a reference while typing code.