Develop Reference

Can Android Studio and Visual Studio safely share the same Android SDK?

I'm trying to free up some disk space and so would like one copy of the Android SDK only, aside from not wanting to maintain two of them. Currently I have one installed for each Android Studio and Visual Studio.
I noticed that there is now a separate, Xamarin specific Android SDK manager that Visual Studio uses in place of the one provided by the Android SDK itself.
Also, Visual Studio's Android NDK is located at "C:\ProgramData\Microsoft\AndroidNDK". I don't recall installing it there specifically (probably used a default location), but suppose Android Studio could be pointed at it as well.

Can Android Studio and Visual Studio safely share the same Android SDK?
The answer is Yes, I have done this for a long time and it works fine.
In Visual Studio, Xamarin Android SDK default location is:
C:\Program Files (x86)\Android\android-sdk
C:\ProgramData\Microsoft\AndroidNDK64
In Android Studio, SDK default location is:
C:\Users\username\AppData\Local\Android\Sdk
C:\Users\username\AppData\Local\Android\Sdk\ndk-bundle
Use Visual Studio Android SDK only
You could refer to my answer:
Open Android Studio, go to File -> Project Structure
Change the SDK location to your Visual Studio SDK Location
a. Change it to Xamarin Android SDK Location: C:\Program Files (x86)\Android\android-sdk
b. There is a problem when you change the SDK Location: cannot contain whitespace. You could open CMD as Administrator and type: mklink /J C:\Program-Files-(x86) "C:\Program Files (x86)", like this.
c. Then you could change the SDK Location, effect.
Use Android Studio Android SDK only
You just need change Xamarin Android settings as the above picture. You could find it in:
Tools -> Options -> Xamarin -> Android Setting
It is that new visual studio specific sdk manager I'm worried about.
As #Muhammad said, it won’t broke anything.

Yes, you can. There is no problem at all. You can specify custom SDK path in both Android studio and Visual studio.

Yes for sure, when install visual studio 2017 you can mark in sdk global in individual components tab, and at the end its a path you referring to it in visual studio and android studio.
If you talk about manage this sdk, visual studio 2015 and older versions of visual studio 2017 uses same android sdk manager but lately there is a new sdk manager related to visual studio only not shared between android studio and visually studio

Android SDK is not listed in IntelliJ

I'm trying to develop an Android app using intelliJ, I've downloaded and installed Android SDK, but I cannot add it.
I've set up the environment variable ANDROID_HOME, and set the "PATH" variable to where my android sdk is + "\platform-tools" (i.e. .....\sdk\platform-tools),
But when I try to android SDK, it's not listed
Any ideas?

You have Android Studio. Why would you bother to install Android SDK in intelliJ?
Android Studio has a purpose of existing. I dont event think it s possible to add android SDK to IntelliJ. Download Android Studio and stop bothering yourself. Google would have said to use to use IntelliJ with Android SDK if it was designed to work like this instead struggling to make a complete IDE.

Can't select android as target in Visual Studio for Mac

I have just installed Visual Studio for Mac (On Mac OS X 10.12.1) and I'm trying to target android with no luck in xamarin forms neither native projects. The Android option is greyed.
If I go to Preferences -> SDK Locations -> Android:
Android SDK
Java SDK
Android NDK
are installed and their path is known by Visual Studio (The three checks are green).
Any idea why is this happening?
Thanks.

"The iOS and Android options will be disabled if neither Xamarin.iOS nor Xamarin.Android is installed. If you install those components then these options should be available.
If you look in the about dialog's Show Details page that should indicate what you have installed."
REF

Visual Studio Cordova project won't build when running on Parallels

I installed Visual Studio on Windows running in Parallels on my Mac.
When creating a new Cordova project and to debug with VS Android Emulator, it fails with:
java.lang.IllegalArgumentException: URI has an authority component
I read somewhere that this happens when sharing is enabled with Parallels. If I disable sharing I get a new error:
java.io.FileNotFoundException: \\Mac\Home\.gradle\wrapper\dists\gradle-2.2.1-all\2m8005s69iu8v0oiejfej094b\gradle-2.2.1-all.zip.lck (The network path was not found)
Which I understand, because \Mac\Home will obviously no longer be available.
What I can't figure out is who or what is looking in \Mac\Home for Gradle, or anything else for that matter. Is it my VS installation? Something in my application? Android SDK? Java? Some NPM package?
Edit:
I'd done a full repair install of Visual Studio, I've reinstalled Node from scratch, Android SDK, and JDK - who knows about \Mac\Home?????

It was Java. \\Mac\Home existed when the JDK was installed, and installing a newer version of the JDK didn't make VS use it - I manually set it in Tools -> Options -> Tools for Apache Cordove -> Environment Variable Overrides

Unity is asking me to locate my Android SDK

All I know is that I have my Android Studio in the applications folder, but it can't be selected.
I'm trying to build a unity project in Android. I'm also using Mac.

You need to find out where Android Studio installed your SDK. You are using Mac but the steps below is for Windows. It should be the-same for Mac too.
Open Android SDK Manager
Get the SDK Location
In Unity, go to Edit->Preferences...->External tools then put the Android SDK location into the SDK slot. Install JDK and put the JDK location in the JDK slot.

Just an add-on to the previous answer:
On the Mac the default location of the Android SDK is here:
/Users/[[Username]]/Library/Android/sdk/
(I would have added that in the comments but I still lack the credits for doing so.)