问题
I would like my Codename One app to react to volume up / down keys (the physical keys that lay on the device side). Actually I already have a button that does the action but I would also like to offer the possibility to use the volume keys to launch the action.
I found the method keyPressed() which prototype reads
public void keyPressed(int keyCode)
but I was not able to actually find the keyCode constant for volume up / down.
How can I assign the volume up / down keys to an action with Codename One ?
Any help appreciated,
回答1:
Key pressed/released won't be invoked for volume since that is way too deep in the native call chain and very device dependent. Volume keys are always treated as a special case so we make them do "what's expected" and provide some tailored callbacks but we don't support the use case of "re-purposing" volume keys.
It might be possible by changing the AndroidImplementation class to include a special case (possibly triggered via a display property) and submitting a pull request for that.
回答2:
hope it's OK to jump on this thread: @Shai, you mention that CN1 "provides some tailored callbacks" for the volume buttons. I tried finding this in the documentation and the code (searching on "volume") but didn't succeed - can you give a hint on how to get such callbacks? My use case is to check if a volume button is pushed when starting up the app and take some special actions.
来源：https://stackoverflow.com/questions/40976239/how-to-assign-an-action-to-the-physical-volume-keys-in-codename-one