On Fri, 9 Nov 2018 11:58:17 +0000, J. P. Gilliver (John) wrote:

I can't see that app. in the store, only on the above page, which only
has a download not an install button (does that mean I'd have to
"sideload" it?). The store does have hundred of other volume controls,
though. (Can't help wondering _why_.)

Hi J. P. Gilliver,
I went through the exact problem, as would anyone who tries to download
that app, that the suggested apps didn't exist on the main repositories.

Whenever I suggest an app, I list three things, to save others that hassle:
1. I list the name of the app (but these are almost never unique)
2. I list the developer of the app (this often is unique)
3. And I list the current URL to the app (which means it exists)

This is a common courtesy honed over decades of being on Usenet, where the
goals, always, is to collaboratively pool our knowledge interactively.

I found that app in question, as I recall, on a web site, but I didn't
trust it, so I didn't download _any_ of the volume-control apps that I
found off the two major sites, Play, and F-Droid. Nor do I recommend others
do so.

Here are the best similar apps I found, untested and in no order yet:

o Volume Lock & Mute, by Dieter Thiess
https://play.google.com/store/apps/details?id=de.dieterthiess.stfu

o Volume + (Easy Control) Free, by yapps
https://play.google.com/store/apps/details?id=il.yavji.volumecontrolads

o App Volume Control, by SpyCorp
https://play.google.com/store/apps/details?id=com.spycorp.appvolumecontrol

o volume control widget for android, by Apps Prime
https://play.google.com/store/apps/details?id=net.appsprime.controller.fx

o Volume App Widget, jmjurado23
https://play.google.com/store/apps/details?id=com.application.volumewidget

o Volume Controller, by Gujarati Infoware
https://play.google.com/store/apps/details?id=com.bhbharesh.VolumeControler

o Volume Widget, by WTW Electronics
https://play.google.com/store/apps/details?id=com.william.soundwidget

o Quick Settings, by F-Droid
https://f-droid.org/en/packages/com.bwx.bequick/

Here is my output from just that last app in the list above:
http://www.bild.me/bild.php?file=3265064audio01.jpg

Notice that means we need to code our Android apps for these outputs:
1. Ringer = loudspeaker?
2. Notification = loudspeaker?
3. Media = loudspeaker?
4. Alarm = loudspeaker?
5. Voicecall = callspeaker?
6. System = loudspeaker?

[Is there any way to get a listing of app.s on the store - such as
volume control ones - that shows parameters, such as size and what
accesses they demand, without going into each app.?]

I agree it would be nice to have that, as some volume control apps asked
for access to contacts, while others didn't ask for access to anything they
didn't need.

My quick-pick heuristic method of finding decent apps is...
1. I google for "best volume control app" (or something like that)
2. I read those reviews and install those apps
3. If any app asks for too much permission, I ditch it.

Then, after installing, I follow a similar quick test algorithm...
1. I run the app and get an idea for what it does
2. If anything bothers me (e.g., pop up ads), I ditch it
3. I keep only the best of the best after that test

Then, during use, I continue to hone down the app list:
1. I put the similar apps in a folder, from best to worst
2. Each time an app does a good job, it moves up in the list
3. Each time an app does a bad job, it moves down in the list

There is more (much more) to the testing process, but that is a quickie.

For example, there is no known way to move the screenshot folder
to where it belongs, on the external SD card in a dir of your choice.
o Is there an free app that will change settings for /Pictures/Screenshots to the external SD Card?
https://groups.google.com/forum/#!topic/comp.mobile.android/pe4pB3oAZ0E

As a workaround to that bug, I'm testing screenshotters as we speak...
http://www.bild.me/bild.php?file=4443440screenshot03.jpg
Where the complete list (with working URLs) is in the related thread.

I practice what I preach because it's what a good Usenet citizen does.