Xamarin compiler conditional for Android greyed out
<p>I am trying to make a new app on Xamarin, first time using it and have run into a problem.</p>

<p>I set it up as:</p>

<ol>
<li>Cross Platform</li>
<li>Single View</li>
<li>target Platforms - iOS and Android</li>
<li>Shared library</li>
</ol>

<p>The problem I have is that in my <code>Database</code> class in the shared section, the Android part of the compiler conditional is not being read.
Whatever I type in there is greyed out and I do not get the predictive text feature as I type.
I am following along a tutorial online but can't see a solution for this.</p>

<pre><code>using System;
using System.IO;

#if __IOS__
using Foundation;
#endif

namespace NoteTaker2
{
    public class Database
    {
        public Database ()
        {
        }

        public static string documentsFolder () {
            string path;

            #if __IOS__
            path = NSFileManager.DefaultManager.GetUrls (NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomain.User) [0].Path;
            #endif

            #if __ANDROID__
            path = Android.App.Application.Context.getExternalFilesDir(null).AbsolutePath; // This line greyed out
            #endif

            Directory.CreateDirectory(path);
            return path;
        }
    }
}
</code></pre>