JSApi Properties for canNavigateBack/Forward

[Martin Pöhlmann]

Bug #1212167 requests back/forward navigation buttons integrated into the service website.
As back/forward navigation is not always possible, it may be wise to display these buttons as disabled and not clickable to resemble the state of the rightclick / "Go" menu.

My sample implementation for Google Music tries to determine if back/forward navigation is possible by emulating the navigation stack.
See: https://code.launchpad.net/~mpdeimos/nuvola-player/bug-1212167/

While this method works in most cases, it has to be duplicated in other service integrations to achieve the same behavior.

A better option would be to expose canNavigateBack/Forward as properties via the JSApi.

[Jiří Janoušek (fenryxo)]

I definitely don't want to implement canNavigateBack/Forward, but more generic Nuvola.isActionEnabled(name).
It might also be useful to send signal when action's state is changed: Nuvola.onMessageReceived("actionChanged", name, enabled)

[Martin Pöhlmann (mpdeimos)]

This definitely makes sense, also wrt to future stuff.

Thinking one step further, it would also make sense to introduce a action java script object, that allows to fire the action and monitor its enabled state?

[Jiří Janoušek (fenryxo)]

Currently implemented in JS API 2.0:
 - Nuvola.updateAction(name, available) - updates availability (sensitivity) of an action
 - Nuvola.triggerAction(name) - triggers an action

See https://nuvolaplayer.fenryxo.cz/contribute/development/javascript_api.html

Planned for JS API 2.3:
 - Nuvola.isActionEnabled(name)
 - Nuvola.onMessageReceived("actionChanged", name, enabled)

It could be possible to create and object that wraps these methods.

Nuvola.getAction(name) -> object Action

object Action:
- name
- isEnabled() -> Nuvola.isActionEnabled(name)
- setEnabled(enabled) -> Nuvola.updateAction(name, enabled)
- trigger() -> Nuvola.triggerAction(name)

[Jiří Janoušek (fenryxo)]

Fix committed to lp:nuvola-player as r792. Will be released in Nuvola Player 2.4.0.
<http://bazaar.launchpad.net/~fenryxo/nuvola-player/trunk/revision/792>

Documantation attached.