It would be great if there was a widget that let the user search for and add content from AGOL. It could be a UI similar to what is used in the Builder/Admin when searching for items belonging to a group, an organization or shared with everyone. Has anyone seen this as a custom widget or heard any rumors regarding this?
If I understand your question, I faced the same problem recently.
You have some informations there: Loading ArcGIS Online Data from a custom Widget
Moreover, in my company, we intend to publish on the GitHub platform some of our custom widgets, which our import widget for adding shape layers or data from ArcGIS Online. Apparently this widget fit your needs, that's why I suggest you to keep you informed of the next evolution of our sharing choices.
Thanks Florian CADOZ - i didn't see that thread before I posted the question. I ended up creating a custom widget that uses the _QueryableLayerSourcePopup-class. And removing the first radio-button (select from map) using css, and activating the second on startup. It's a good enough solution for now. It would be great if you tell me when you have something up on GitHub.
Robert Scheitlin - thanks for the tip, but that widget was slightly too simple (just swapping webmap using a url-parameter).
I guess Esri Inc will come up with a widget for this use-case soon, as it is a fairly natural functionallity in AWAB.