Provide a way to silence Talkback speach on the fly

[GoogleCodeExporter]

I am using a Nexus 7, which does not have a proximity sensor. If I wish to 
utilize any form of speech recognition, Talkback often talks over me, making 
dictation impractical.
Talkback requires a way to get it to shut up some sort of relatively-easy 
gesture.
This is more-generally useful and should not be fixed by simply having Talkback 
silence itself during dictation.

Original issue reported on code.google.com by Q.Alpha@gmail.com on 12 Jan 2013 at 10:59

[GoogleCodeExporter]

On Android 4.2 and above, TalkBack 3.2.1 will silence as soon as you touch the 
screen.  This sometimes results in a new item on the screen getting focused and 
speaking.  In that case, just touch again at the same point and speech will 
stop.

We'll continue brainstorming more intuitive ways for silencing speech.  We 
prototyped using the ambient light sensor on devices without a proximity 
sensor, but found as people changed lighting environments, speech would silence 
unexpectedly.

Original comment by caseybur...@google.com on 12 Feb 2013 at 3:37

• Changed state: Fixed