Yes but why is it only the user's responsibility to contact Google to advocate for this? Shouldn't the developer be working with Google to correct the issue as well? This whole thing about the user "asking the right people" philosophy just doesn't sound right to me IMHO.
If you are really interested in knowing how Android supports and ensures interactions between different apps I recommend to read the relevant technical article(s).
Quote from Android's Developer page:
http://developer.android.com/training/basics/intents/sending.htmlOne of Android's most important features is an app's ability to send the user to another app based on an "action" it would like to perform. For example, if your app has the address of a business that you'd like to show on a map, you don't have to build an activity in your app that shows a map. Instead, you can create a request to view the address using an Intent.
The Android system then starts an app that's able to show the address on a map.
Please be aware :
This feature (
create a request to view a pdf-file using a PDF Viewer app)
is already well implemented in AquaMail. > please try out how it works within a native Android system like Lollipop or Marshmallow on a mobile device (mobile phone, tablet)
Another part from Android's Developer page:
http://developer.android.com/training/basics/intents/filters.htmlAllowing Other Apps to Start Your Activity If an app (e.g. PDF Viewer app) can perform an action that might be useful to another app (e.g. a mail client like AquaMail),
the PDF Viewer app should be prepared to respond to action requests from other apps. For instance, if you build a social app (a PDF Viewer app) that can share messages or photos with the user's friends (that can view PDF files / attachments), it's in your best interest to support the ACTION_SEND intent so users can initiate a "share" action from another app and launch your app to perform the action.
To allow other apps to start your activity, you need to add an <intent-filter> element in your manifest file for the corresponding <activity> element.
the responsibility for this is definitely on the side of the PDF Viewer developer(!)To summarize in short:
The responsibility to ensure that the PDF-Viewer app will appear in the "App Chooser list" is (just and only) on the side of the 'action' app, in particular in the hands of the PDF Viewer app respectively of their developer(s), or even on the side of Google's dev team "Android inside Chrome OS".
About the "App Chooser":
http://developer.android.com/training/basics/intents/sending.html#AppChooserAttached you will find a screenshot, which shows available PDF-Viewer apps when I want to open a pdf attachment within AquaMail (provided by Google's Android OS... definitely
not by AquaMail itself)