No items found during loading playlist preview

[pavelevap]

For a quick while after opening post with inserted playlist, there is message "No items found." It is only for a sec, but it catching my attention. After a sec, there is nice playlist. But this message is not needed, I guess. Maybe loading indicator would be much better (or simply white box)? And display message only when there are really no items...

[gcorne]

27899-01.patch​ adjusts how rendering is handled for the playlist wpview to simplify the code and also to fix this issue and an issue where the undo stack would get "stuck."

@wonderboymusic should probably give this a read and do some testing before it is committed.

[wonderboymusic]

27899.diff​ is my revision - I think your patch was stale against trunk, it wouldn't apply. However, I pulled the necessary pieces out and revised the player unsetting logic to always assume an array, players are always pushed onto a stack when added. Due to the possibility of multiple editor instances, each View instance is always responsible for potentially multiple shortcode instances.

[gcorne]

For those following along, I think the issue with 27899-01.patch​ not applying was because I based the patch off the 3.9 branch.

Nonetheless, 27899.3.diff​ takes the improvements that @wonderboymusic made in 27899.2.diff​ and switches to the unsetting the players using unbind(), which should work a bit better when the full DOM is rebuilt by TinyMCE. Everything else seems to be working well.

[wonderboymusic]

In 28182:

Refinements for asynchronous rendering in wp.mce.media.PlaylistView:

• Add visibility: hidden as an inline style to <audio> tags, there is a race with the stylesheet which can get enqueued in the body and loaded in the footer.
• When creating new instances of MediaElementPlayer, always push them onto a stack. Lone views can be responsible for multiple instances of the same shortcode on render.
• Rename wp.media.mixin.unsetPlayer() to wp.media.mixin.unsetPlayers() to reflect the above.
• Call wp.media.mixin.unsetPlayers() on the view's unbind() method, instead of inline in the render() method
• Make sure WPPlaylistView is instantiated for each editor instance
• Ensure that the No Items Found view state is not rendered when attachments actually do exist.

Props gcorne, wonderboymusic.
See #27899.

[pavelevap]

Nice, no more annoying message, media items are loaded gradually in editor. I did not find any problem...

[nacin]

In 28272:

Refinements for asynchronous rendering in wp.mce.media.PlaylistView.

Merges [28182] to the 3.9 branch.

props gcorne, wonderboymusic.
fixes #27899.