Recipe 22.8. Responding to the Soft Keys

Problem

You want to respond to the user pressing the phone's soft keys.

Solution

Use an offstage button instance to respond to the key press.

Discussion

In the previous section, you learned how to register and relabel the phone's soft keys. After the soft keys have been registered, you can respond to soft key presses.

The left and right soft keys are mapped to the same keycodes as the page up and page down keys on a traditional keyboard. Therefore, to detect when the user has pressed the left soft key, you will handle the keyPress event for the <PageUp> keycode. For the right key, you will handle the keyPress event for the <PageDown> keycode. In either case, the convention is to use a button placed offstage in order to handle the events. This method allows you to "listen" for the key presses regardless of whether your user interface calls for an actual button.

1. Insert a new symbol (Insert New Symbol…) and select the Button behavior. The name you enter will be used to identify this button in the library.

3. Exit the symbol editing mode (Edit Edit Document or click on the scene in the Edit Bar).

4. Select the button instance.

5. Open the Actions panel (Window Development Panels Actions or F9). The title bar of the Actions panel should read "ActionsButton."

6.