Develop Reference

Which versions of Android support native action and share sheets?

I'm making improvements to an application and I'd like to use the native Android bottom sheet, allowing users to select an option as well as the native Android sharesheet for sharing content.
I have a small userbase that is on Android 9 and an even smaller userbase that is on Android 8. I'd like to measure the impact on these users, though can not find any documentation of which Android versions support these native UI elements.
Images for reference: Bottom sheet + Share sheet

I'd like to use the native Android bottom sheet
That is not "native", insofar as it is not part of the Android SDK. You can get a bottom sheet from the Material Components for Android, which is the official implementation of some of the advanced UI elements from the site that you linked to. It works back to API Level 14 (Android 4.0).
as well as the native Android sharesheet for sharing content
ACTION_SEND works back to Android 1.0. What the visual presentation will be is up to the device manufacturer; you and I do not get a vote.

Is it possible to make an android app through android studio using html 5 code?

I have made a website using HTML5.
However, I'm trying to make the app using the CSS, JavaScript and HTML I used for the website. Is that somehow possible?
I must use Android Studio.

Nope, you can't do that.
Android Studio is based on Java (logic) and XML (design).
XML and CSS are a little bit similar. You have paddings and margins too.
However. Prepare yourself to put work into the project.
But why do you need an app when you can also show the same contents in a website that works on way more devices? You can also use a WebView to show your website in the app.
If it must be native and you can't use a WebView, just rebuilt the design, Check out the material design guidelines, stick to them and your app will be easy to use for the users and look awesome.
Links:
https://material.google.com/ (read through the components stuff)
https://design.google.com/icons/ (all icons)

React native modal blur/vibrancy on iOS and Android?

I'm trying to build a modal that looks somewhat like this using React Native for iOS and Android. Are there any libraries that do blurred/vibrancy overlays? I had a look at the react-native-blur, however unfortunately this is only for iOS. React-native-overlay also has some options for such views, however it also appears to be iOS only.
Is there a library that supports both platforms, or is there a way to use a JS library such as vibrancy.js that can be used with React?

Currently react-native-blur supports blur for Android as well. However a little bit of setup is required. Check out the docs here:
https://github.com/react-native-community/react-native-blur.
The library also offers the ability to create vibrancy views. Although, at the present (v 3.2.2), vibrancy will only work fo iOS.

Doing an Android sliding drawer without the support APIs

I'd like to add a sliding drawer to my app which is using the min sdk version of 16 and a target sdk of 21 and should allow it to use the most recent features of the platform.
I looked around on how to implement a sliding drawer, and all the articles I found talk about using some support APIs to do just that.
My app is not yet using these support APIs.
I wonder if implementing the sliding drawer is possible without any support APIs, and if so, if there is any resources showing just that.

DrawerLayout, the basis for Creating a Navigation Drawer is only found in the Android Support Library (along with many other Support Library only APIs). There is nothing in the Android framework that provides this same functionality.
To provide the most consistent experience to users, you should just use the Support Library.

You should consider using support APIs, but if you really dont want to, you can use user-created library.
Here's one I used for one of my projects:
https://github.com/mikepenz/MaterialDrawer

Yes, it is always possible. However, the DrawerLayout class is available only in support libraries.
When I first realized that, it made no sense to me. But now I see support libraries as an extension of the core libraries (android.*).
Anyway, I recommend using the support libraries or you will have to create the logic to do exactly the same from scratch.

You can use android design support library, it's working on all devices in android and it's open source so you can edit it as you like with custom element.
Here's a reference how to implement Navigation drawer using new android support library

Get groups/id from svg image in android

I am developing an android app using the library androidsvg. Basically, I'm using an svg image as a map, each part of the map has it own group and id.
Is it possible to get the id's and add onClick listeners using only one svg img? If not, any suggestions about how to do that?

AndroidSVG is just a rendering library. It has no support for interactivity (yet - it is on the todo list).
In the meantime the simplest solution is probably just to use a WebView. Be aware though that WebView only has native support for SVG from Android 3.0 on. If you need to support earlier versions of Android, there are ways to do it with JS polyfills. See: Android webView support for svg rendering.