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Xamarin forms how to make a graphical custom UI component

I'm learning Xamarin (Forms) at the moment and I want to create a special component for my app so I'm looking for some guidance to get me started.
I'm imagining a component which has a main button in the middle, with text that could be "Birds" followed by the number of birds spotted this week.
Then, for each species spotted this week, there would be a line leading to the species name and the aggregated number of how many of that species have been spotted (so x number of lines). Basically a kind of a grouping diagram which acts like buttons.
I drew it up in mspaint, just without numbers.
I imagine my first step working with Xamarin Forms is to create the component in both Android Studio and Xcode, then package it as an component.
Can my idea be done in both Android and iOS? If so, would you please provide some tutorials on creating something like it, because I haven't come across something that I can use to get started yet.
UPDATE: SkiaSharp looks like the way I should be going.. https://developer.xamarin.com/guides/cross-platform/drawing/introduction/

Xamarin allows you to build mobile apps completely in C# so you don't need native development tools (like Android Studio and Xcode) all development can be done completely in Visual Studio (Mac or PC).
You can totally make what you're describing with Xamarin Forms! In order for you to do it, you must make a Custom Render. See this guide on Xamarin's website for making a custom renderer.

Ui like android sliding notification bar for web (html)

I am building a desktop app using electron (formerly known as node atom, using html javascript and css).
I want to use (or create if there is no choice) a sliding notification bar, like the one on android OS.
I failed to find existing components for this purpose and not sure how to develop this component myself.
I would like to know if such component or something similiar exists or how I could write one for my own use.
Thanks alot in advance for the help
Update 1
I was requested, rightfully, to give more info and be more specific.
I will expand on exactly what I need from this status bar, and why I need it and the context in which I need it for. (maybe there are better options that i'm not aware of).
I am writing a desktop app using nodejs electron (so my UI doesn't follow the common browser ui&ux rules).
The template that I have written so far looks like the following:
as you one can see, im trying to make it look as much as "mobile" I can while following google material design (i'm using angular 2, so angular 1 material is not an option, most of the component i'm using are from polymer elements collection)
The heart of my app is about running some algorithms on the server. I want a central place to show which algorithms are currently running and their status (there cant be more then 5 at once usually), so the only idea I could think of that fits material design and is central enough was to use something that looks like the android notification bar. The problem is that I couldn't find any web component that can achieve that. The status bar which i'm talking about looks like the following (The way it looks change a bit when looking at numerious android version, I don't mind exactly like which version it looks like). It should slide down from the top when clicked or dragged down like in an android mobile phone:
The notifications show whats currently active, I could also use a setting shortcut in it as well (The marked in red areas are the relevant parts). The rest of the options are not relevant.
So that's what I was initially looking for. If someone has a better idea on how to show these running algorithms in a central place, that fits the material design guidelines, I am also open to suggestions :)

Is there a way to change the spacing of Android buttons on cordova-plugin-dialogs?

I developed a hybrid mobile app.
I was wondering myself if there is a way to change the space between buttons raised from cordova-plugin-dialogs on Android.
They usually look like:
I'm not very familiar with native development (on Android), so is there anything I can change to affect the spacing of those buttons? e.g. on Android manifest or something?
Thanks in advance!

The solution here falls in the "Create your custom dialog in Android" solution, actually. Those are the default dialogs, and the buttons are generated automatically. I don't think you can control anything else than the theme, texts and pretty much that's it.
If you want to be able to completely modify it, create a custom native dialog (for each platform you're targeting, if possible in iOS -not sure right now), and create a cordova plugin that opens that dialog, and returns something when the buttons are clicked...
Or simply create a "dialog" (modal) in html. That will be much simpler, if you're already using cordova.

Can you detect with jQuery (or anything, but C++) if the volume button is pressed?

I doubt it is, but is it possible to detect if the volume button is pressed, by jQuery or any of the web languages?
I want to do some basic user testing, to investigate by which way it's best to call a certain function; either a gesture or a hardware button. I't not a problem to call a function based on a touch gesture, but calling a function based on pressing a hardware button is a bit more difficult.
As I got both an Android phone and iPhone here, it doesn't matter if it only works on one of both devices.
Since I can't write C++, this language isn't an option. Even though this language does support hardware button detection
What I want to create
It's the most basic version of a test: I want to see by which way people would like to switch from round to squared display.
There is a simple round object in the center and it should transform to a square, based on any of the following gestures: A hardware button press (volume), pinch, pinch-out, 4-finger pinch out, 2 finger swipe down.

Short answer:
If you're running this in a mobile browser (e.g. Safari or Chrome), you don't have access to the volume buttons.
Explanation:
JQuery relies on JavaScript which relies on a browser, webview (for native apps), or a node.js server (irrelevant for you). Webviews tend to be like a browser but with fewer features. The main browsers out there do not provide access to the volume buttons. Therefore, jQuery isn't going to solve this for you.
Solution:
You're going to need a native app if you really want to use the volume buttons. On Android, apps are written in Kotlin (based on Java). On iOS, they're written in Swift (or Objective-C). If you know only one or none of those languages, there are cross-platform tools that'll let you write the app once and deploy to both platforms. Depending on the level of control you want, you could use a tool that provides a unified framework or go for a fancy drag-and-drop builder. There are TONS of options out there.
Extra:
Looking at your history, it seems like you're a "web" guy. If you just want to use jQuery/JavaScript for the convenience, you could create a simple native app that basically does just two things: 1) Load your webapp, and 2) Provide an API to the webapp for accessing the volume buttons. This topic will get you moving in that direction: Calling android native APIs from javascript functions of embedded WebView
I encourage other web folks to hack around a little on mobile platforms. You never know when a base level understanding could come in handy.

What's the android design pattern for multiple pages?

I'm working on an android app that has a section that feels like an iPhone home screen. There's a bunch of pages that are essentially displaying the same data in different configurations and users should be able to quickly move between them. Generally there won't be more than 4 or 5 pages.
I could just replicate the experience with the iPhone home screen with multiple dots on the bottom of the page, but that doesn't feel very android-friendly. What's the design pattern in android for viewing and interacting with this type of view? I know the android home screen has a variant with dots, but I've never seen it used within an app.
Screenshots or links to existing apps would be great.

The stock Android launcher has left/right paging behavior on the home screen, and it's open source.
This is the Workspace class. Pay special attention to the onTouchEvent and onInterceptTouchEvent methods. The utility classes Scroller and VelocityTracker are used together to define the behavior for snapping to a page when the user lets go from a drag.
https://android.googlesource.com/platform/packages/apps/Launcher2/+/master/src/com/android/launcher2/Workspace.java

Hootsuite uses this design pattern and it works well in my opinion. I don't think it affects the user experience on Android in a negative way. I find that the biggest problem with people porting iPhone applications to Android is the fact that they try to port every single design pattern over. I don't think what you're trying to implement will be an issue.