Qt Creator can't find ANDROID_NDK_ROOT environment variable

[istlota101]

Re: Qt + Android (ANDROID_NDK_ROOT environment variable...)

I used Qt Maintenance Tool to confirm that I installed all the Android related stuff for Qt v5.13.2. Then, I used the following link to install the v2.1 Android NDK on my Ubuntu platform:
https://www.lynxbee.com/how-to-install-android-ndk-on-ubuntu-16-04-18-04/

But, note, that procedure EXPORTs the android NDK's folder to PATH, but does NOT set the ANDROID_NDK_ROOT environment variable. Hence, here is all the android NDK stuff I added to the end of my .bashrc file:

Android NDK stuff

export PATH=$PATH:~/android-ndk-r21
ANDROID_NDK_ROOT=~/android-ndk-r21

After that, issuing this bash cmd confirmed that my platform knows where the android NDK is:
which ndk-build

And, issuing this bash cmd confirmed that the environment variable was now known by my platform:
echo $ANDROID_NDK_ROOT

Nevertheless, Qt Creator's General Messages window reported it could not find the ANDROID_NDK_ROOT environment variable, And, sure enough, the Build Settings of Qt Creator's Project dialog dialog did NOT list the ANDROID_NDK_ROOT environment variable, not even after I rebooted my computer.

I manually added the ANDROID_NDK_ROOT variable to Build Settings and that got rid of this problem.

Oh, but it gets better. I then unset that variable from the Build Settings and QT Creator NOW no longer gets the General Messages warning, even though Build Settings no longer lists the ANDROID_NDK_ROOT variable.

Now, I avoid reinstalling Qt from scratch every time some weird issue like this arises, mainly because even if that 'kludge' works, you still do not know WHY it now works.

Ergo, I no longer have the problem, but I STILL don't know why Qt now can find the installed Android NDK. I am posting this because this HAS to be some deficiency in how Qt Creator processes system environment variables (not just ANDROID_NDK_ROOT) and I am hoping some codemeister will read this and a light bulb will go on over his head as he experiences that infamous AH-HA moment.

[jsulm]

@istlota101 In QtCreator you can actually define where NDK is on the "Devices" tab in Options