[talkback] When I use volume key to silent the ringtone, media volume go up or down

[GoogleCodeExporter]

When I use volume key to silent the ringtone, 
if I press the volume up,  the media/talkback volume will go up to 100%.
if I press the volume down, the media/talkback volume will go down to 0%.

nexus5, nexus4, android 4.4.2, talkback 3.5.1

Original issue reported on code.google.com by infosiec...@gmail.com on 28 Mar 2014 at 11:01

[GoogleCodeExporter]

I think this is not an issue but rather this is a feature.
While a sound is playing e.g. multimedia player, online web app in a web 
browser or while using other apps you can change the media volume by pressing 
the volume rocker buttons.
When there is no sound playing pressing these buttons is designed to control 
ringer volume instead.
Sound of text to speech components is also considered to be a media volume. So 
while talkback is speaking pressing volume rockers naturally controls overal 
device's media volume.
When sound playback is done including text to speech output there is a 
hardcoded timeout we need to wait in order to be able to change the ringer 
volume.
So in order to change the ringer volume we should perform the following steps:
* Activate proximity sensor to interupt text to speech output if it's speaking
* Wait a little while e.g. from 10 to 20 seconds
* Use volume rocker buttons to adjust ringer volume.

In current versions of Android I don't know when this has been introduced 
pressing one of the volume buttons displays a pannel where you can switch which 
volume to control by tapping the respective slider.

I can't think of a more natural usage patterns than this. I don't think we will 
see a change regarding how this is implemented since it may affect all the 
Android users not just those relying on Google Talkback and other accessibility 
related technologies.

Original comment by pvdee...@gmail.com on 5 Sep 2015 at 8:28