The attribute android:onClick="FabOnClick" crashes app when Floating Action Button clicked - xamarin.android

Question

There doesn't appear to be a lot of people using Xamarin for Visual Studio consequently there isn't a lot of information specific to that platform out there.
Having said that, I've been trying to get a Floating Action Button (FAB) to work and it's been quite the exercise. I finally got it to appear and assign it to a variable in the activity with help from the nice folks who use StackOverflow, but cannot get the android:onClick="FabOnClick" call to work. Clicking on the FAB causes the app to crash with the error:
Unhandled Exception:
Java.Lang.IllegalStateException: Could not find method FabOnClick(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.design.widget.FloatingActionButton with id 'fab' occurred
This is the code in my activity:
public void FabOnClick(View v)
{
int x = 1;
}
It doesn't really do anything because I'm just trying to capture the click event for now. I set a breakpoint on the int x = 1 line to see when it's is executed. So what am I missing?
* Update *
I updated my activity code based on #Digitalsa1nt's answer below:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Acr.UserDialogs;
using Android.Net;
using System.Net;
using Android.Support.Design.Widget;
using System.Threading.Tasks;
using Android.Views.InputMethods;
using static Android.Views.View;
namespace OML_Android
{
[Activity(Label = "CreateAccount")]
public class CreateAccount : Activity
{
public string result = "";
public EditText aTextboxUsername;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.CreateAccount);
RequestedOrientation = Android.Content.PM.ScreenOrientation.Portrait;
aTextboxUsername = FindViewById<EditText>(Resource.Id.aTextboxUsername);
EditText aTextboxPassword = FindViewById<EditText>(Resource.Id.aTextboxPassword);
EditText aTextboxPassword2 = FindViewById<EditText>(Resource.Id.aTextboxPassword2);
EditText txtEmailAddress = FindViewById<EditText>(Resource.Id.txtEmailAddress);
EditText txtEmailAddress2 = FindViewById<EditText>(Resource.Id.txtEmailAddress2);
EditText txtFirstName = FindViewById<EditText>(Resource.Id.first_name);
EditText txtMI = FindViewById<EditText>(Resource.Id.mi);
EditText txtLastName = FindViewById<EditText>(Resource.Id.last_name);
EditText txtAddress = FindViewById<EditText>(Resource.Id.address);
EditText txtCity = FindViewById<EditText>(Resource.Id.city);
Spinner spnState = FindViewById<Spinner>(Resource.Id.state);
EditText txtZip = FindViewById<EditText>(Resource.Id.zip);
MaskedEditText.MaskedEditText txtPhone = FindViewById<MaskedEditText.MaskedEditText>(Resource.Id.phone);
Spinner spnCompany = FindViewById<Spinner>(Resource.Id.company_spinner);
Spinner spnDept = FindViewById<Spinner>(Resource.Id.department_spinner);
Spinner spnSection = FindViewById<Spinner>(Resource.Id.section_spinner);
Button ButtonSubmit = FindViewById<Button>(Resource.Id.button_submit);
ScrollView sv = FindViewById<ScrollView>(Resource.Id.scrollView1);
ButtonSubmit.SetBackgroundColor(Android.Graphics.Color.YellowGreen);
// Hide the keyboard (also doesn't work)
InputMethodManager board = (InputMethodManager)GetSystemService(Context.InputMethodService);
board.HideSoftInputFromWindow(aTextboxUsername.WindowToken, 0);
// get the floating action button.
FloatingActionButton myFab = FindViewById< FloatingActionButton>(Resource.Id.fab);
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
DataInterfaceWeb.DataInterface myService = new DataInterfaceWeb.DataInterface();
myFab.Click += FabButton_Click(); // <-- get error here
try
{
ConnectivityManager connectivityManager = (ConnectivityManager)GetSystemService(ConnectivityService);
NetworkInfo activeConnection = connectivityManager.ActiveNetworkInfo;
bool isOnline = (activeConnection != null) && activeConnection.IsConnected;
if (!isOnline)
{
showMessage("There is no internet or cell phone connection. Connect to a network or connect to a cellular network.", "ERROR");
}
}
catch (Exception ex)
{
showMessage("Connectivity Manager failed to create a connection due to error: " + ex.Message, "ERROR");
};
// Create your application here
ButtonSubmit.Click += async (sender, e) =>
{
try
{
result = myService.CheckForUser(Master.username, Master.password, aTextboxUsername.Text);
if (result.ToUpper() == "Y")
{
await showMessage("Username " + aTextboxUsername.Text + " is already in use. Please choose another", "ERROR");
// aTextboxUsername.SetSelectAllOnFocus(true);
aTextboxUsername.RequestFocus();
View insideView = FindViewById<EditText>(Resource.Id.aTextboxUsername);
sv.ScrollTo(0, (int)insideView.GetY());
aTextboxUsername.SelectAll();
}
}
catch (Exception ex)
{
showMessage("Account creation attempt failed due to error: " + ex.Message, "ERROR");
}
};
}
public async Task showMessage(string message, string messageType)
{
var result = await UserDialogs.Instance.ConfirmAsync(new ConfirmConfig
{
Message = messageType + System.Environment.NewLine + message,
OkText = "Ok",
});
}
public void FabButton_Click()
{
int x = 1;
}
}
}
The error I get now is:
Cannot implicitly convert 'void' to 'SystemEventHandler' on the line myFab.Click += FabButton_Click();.

Answer 1

#Digitalsa1nt did point me in the right direction. Instead of
fabButton.Click += FabButton_Click;
I just wired up an event, as the error suggested (duh):
myFab.Click += (sender, e) =>
{
FabButton_Click();
};
It now works as I would expect.

Answer 2

So I'm making a couple of assumptions in this answer. Firstly that you are working with a Xamarin.Native project and not a Xamarin.Forms project.
Secondly I am assuming you are using the FloatingActionButton from one of the support libraries such as: Android.Support.Design.Widget (base / V4 / V7).
Once you've defined your FAB within the AXML Layout page:
<android.support.design.widget.FloatingActionButton
app:backgroundTint="#color/colourPrimary"
android:id="#+id/fabButton"
android:src="#drawable/image"
app:fabSize="normal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:elevation="16dp"
android:translationZ="12dp"
app:rippleColor="#ffa9a9a9" />
You can get it from within your activity as such:
using Android.Support.Design.Widget;
// declare variable
private FloatingActionButton fabButton;
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// call base
base.OnCreateView(inflater, container, savedInstanceState);
// inflate our view
var view = inflater.Inflate(Resource.Layout.MainTabWishlistPage, container, false);
// get our instance of the button using the resource ID.
fabButton = view.FindViewById<FloatingActionButton>(Resource.Id.fabButton);
// assign to click event
fabButton.Click += FabButton_Click;
}
private void FabButton_Click(object sender, EventArgs e)
{
int x = 1;
}
The above example is based on it being a fragment rather than an activity, but the methodology is the same.
Official Git Repo:
Xamarin/monodroid-samples - Floating Action Button Basic
Random online guide:
android-material-design-floating-action
In case this is a Xamarin.Forms project, look into James Montemagno's library (p.s one of the developers that works on Xamarin and creates tons of libraries to help make your life easier, definitely look through his other repos.)
jamesmontemagno/FloatingActionButton-for-Xamarin.Android