How to make Zebra Xing (Zxing) as subview in Xamar

In my Xamarin.Android app, I want to use ZXing to scan barcode. I want to display the scanner in the view of an activity.

Code:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:weightSum="5">
    <Button
        android:text="Scan with Default Overlay"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/buttonScanDefaultView"
        android:layout_weight="1" />
  <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/scanView"
        android:layout_weight="2" />
</LinearLayout>

protected override void OnCreate (Bundle bundle)
{
    base.OnCreate (bundle);
    scannerFragment = new ZXingScannerFragment ();
    scannerFragment.CustomOverlayView = CustomOverlayView;
    scannerFragment.UseCustomOverlayView = UseCustomOverlayView;
    scannerFragment.TopText = TopText;
    scannerFragment.BottomText = BottomText;
    this.FragmentManager.BeginTransaction ()
                .Replace (Resource.Id.scanView, scannerFragment, "ZXINGFRAGMENT")
                .Commit ();
}

I'm getting an error stating that I cannot convert support.v4.fragment into android.app.Fragment.

Can anyone advise what I'm doing wrong and how should I approach this to get the scanner view (of ZXing) in a layout of my current activity.

ZXingScannerFragment derives from Android.Support.V4.App.Fragment while the Activity.FragmentManager expects fragments derived from Android.App.Fragment.

Now, how to fix that:

Inherit your activity from any activity that works with Android.Support.V4. Easiest would to use Android.Support.V4.App.FragmentActivity from package Xamarin.Android.Support.v4 that is already installed by ZXing.Net.Mobile package as a dependency.
When you have correct activity, you can use this.SupportFragmentManager instead of this.FragmentManager to work with Support.V4-based fragments.

So, layout you have is good. Code should be updated to something like:

using Android.App;
using Android.Widget;
using Android.OS;
using ZXing.Mobile;
using Android.Support.V4.App;

namespace ZXingSample
{
    [Activity(Label = "ZXing Sample", MainLauncher = true, Icon = "@mipmap/icon")]
    public class MainActivity : FragmentActivity
    {
        int count = 1;

        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            SetContentView(Resource.Layout.Main);
            var scannerFragment = new ZXingScannerFragment();
            scannerFragment.UseCustomOverlayView = false;
            scannerFragment.TopText = "Scan your code";
            scannerFragment.BottomText = "Then proceed";
            this.SupportFragmentManager.BeginTransaction()
                        .Replace(Resource.Id.scanView, scannerFragment, "ZXINGFRAGMENT")
                        .Commit();
        }
    }
}

Launching the app, you will see your scanner: