How is the default "open with" or "open as" file type set in Android 9?

Arlen Holder

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Feb 23, 2020, 11:04:07 PM2/23/20

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How can I set Android Pie to "Open as..." or "Open with..." any given file
name extension (e.g., test.tc) with a given application (e.g., EDS Lite)?

*How is the default "open with" file type set for *tc files in Android 9?*

For example, I have TrueCrypt files created & maintained on Windows which I
wish to "Open with..." EDS Lite when "test.tc" is copied to Android.
o <https://f-droid.org/en/packages/com.sovworks.edslite/>
o <https://play.google.com/store/apps/details?id=com.sovworks.edslite>
o <https://sovworks.com/eds/>

Currently, when I tap on the "test.tc" file in the Android file explorers,
the available choices do _not_ include "EDS Lite".

All I want is to set the "Open with" or "Open as" in Android for *.tc files
to open with (or open as) "EDS Lite" files, by default, even though EDS
Lite doesn't show up as a choice when I currently tap on "test.tc" files.

How is the default "open with" or "open as" file type set in Android 9?

Arlen Holder

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Feb 23, 2020, 11:36:54 PM2/23/20

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On Mon, 24 Feb 2020 04:04:07 -0000 (UTC), Arlen Holder wrote:

> How is the default "open with" or "open as" file type set in Android 9?

I'm not sure, but it seems a formal "mime type" is what Android may use:
<https://www.freeformatter.com/mime-types-list.html>

I couldn't find any mime-type reporting programs on F-Droid:
<https://search.f-droid.org/?q=mime+type>

We could create our own mime-type reporting tool if we really wanted to:
<https://www.edumobile.org/android/get-file-extension-and-mime-type-in-android-development/>

But I found two existing mime-type reporting programs on Google Play:
o Ampare MIME Type Checker, by Ampare Engine [no ads, GSF independent]
<https://play.google.com/store/apps/details?id=com.juthawong.android.mimechecker>
o aA MIME type detection, by VISION CRAFT [contains ads, GSF dependent]
<https://play.google.com/store/apps/details?id=jp.visioncraft.filelist>

While the "aA" mime detector was obnoxious, so I instantly deleted it,
neither one reported _anything_ set as the mime type for *.tc files.

So the question remains, for an unrooted Android Pie device, how do we set
any given file (e.g., "test.tc") to open in any desired app (such as "EDS
Lite") in any given file explorer application (e.g., "File Manager") when
we simply tap on the file in Android 9?

David Oseas

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Feb 24, 2020, 12:37:51 PM2/24/20

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On 2/23/2020 8:36 PM, Arlen Holder wrote:

>> How is the default "open with" or "open as" file type set in Android 9?

Android appears similar to Windows in that it uses file extension to
determine filetype, unlike Linux-like OSes that use a signature or
MIME-type.

To verify this, use a file manager to rename a file to a different
extension. If the extension you use is unknown (ex: .tmp or make up one
of your own), you will be prompted to search for an appropriate app.

AFAIK, apps declare which filetypes they handle in the manifest and that
info is added to your launcher's database when the app is installed.
Depending on the launcher, the first app installed may become the
default for the filetype, or the launcher will not set any default and
will prompt you each time you try to open the filetype ("once" or
"default").

You can clear a program that is set as a default for a filetype (or an
action) through the Settings applet; there is a "Set as default" section
near the bottom of each application.

There are also utilities that will allow you to manipulate the defaults
outside of Settings. The one that I have installed is called "Default
App Manager", which was sufficient for the purpose that I needed, but
there are probably better ones out there.

Regards,

-David

Arlen Holder