CustomDroidViewsContainer.cs

namespace OurProj.Framework.Droid.Views
{
    using System;
    using System.Collections.Generic;

    using Android.Content;

    using Cirrious.MvvmCross.Droid.Views;
    using Cirrious.MvvmCross.ViewModels;
    
    /// <summary>
    /// Custom AndroidViewsContainer used solely to stop the NewTask activity flag from being added to the LoginView Intent fired after Unlock
    /// </summary>
    public class CustomDroidViewsContainer : MvxAndroidViewsContainer
    {
        /// <summary>
        /// A list of the activities shown with ActivityFlags.NewTask and ActivityFlags.ClearTask
        /// </summary>
        private List<string> activitiesShownWithNewAndClear = new List<string>(); 
        
        /// <summary>
        /// Initializes a new instance of the <see cref="CustomDroidViewsContainer"/> class.
        /// </summary>
        /// <param name="applicationContext">The application context.</param>
        public CustomDroidViewsContainer(Context applicationContext) : base(applicationContext)
        {
        }

        /// <summary>
        /// Loads the specified intent.
        /// </summary>
        /// <param name="intent">The intent.</param>
        /// <param name="savedState">State of the saved.</param>
        /// <returns>Some cool stuff</returns>
        public override IMvxViewModel Load(Intent intent, IMvxBundle savedState)
        {
            this.LogIfClearTaskNewTask(intent);
            
            return base.Load(intent, savedState);
        }
        
        /// <summary>
        /// Loads the specified intent.
        /// </summary>
        /// <param name="intent">The intent.</param>
        /// <param name="savedState">State of the saved.</param>
        /// <param name="viewModelTypeHint">The view model type hint.</param>
        /// <returns>Some cool stuff</returns>
        public override IMvxViewModel Load(Intent intent, IMvxBundle savedState, Type viewModelTypeHint)
        {
            this.LogIfClearTaskNewTask(intent);

            return base.Load(intent, savedState, viewModelTypeHint);
        }

        /// <summary>
        /// Adjusts the intent for presentation.
        /// </summary>
        /// <param name="intent">The intent.</param>
        /// <param name="request">The request.</param>
        protected override void AdjustIntentForPresentation(Intent intent, MvxViewModelRequest request)
        {
            // The default MvxAndroidViewsContainer code add ActivityFlags.NewTask to all Intents. 
            // This is a problem when an Activity has subsequently been shown using the combination of NewTask and ClearTask
            if (this.activitiesShownWithNewAndClear.Contains(intent.Component.ClassName))
            {
                // I wanted to remove the NewTask flag that base.AdjustIntentForPresentation 
                // added as a default but Flags is a readonly property so just going to have to skip 
                // base.AdjustIntentForPresentation(intent, request); 

                ////ActivityFlags flags = intent.Flags;
                ////flags &= ~ActivityFlags.NewTask;

                ////intent.AddFlags(flags);
            }
            else
            {
                base.AdjustIntentForPresentation(intent, request);    
            }
        }

        /// <summary>
        /// Logs the Intent's Component class name if the Intent is being shown as a ClearTask and NewTask
        /// </summary>
        /// <param name="intent">The intent.</param>
        private void LogIfClearTaskNewTask(Intent intent)
        {
            if (intent.Flags.HasFlag(ActivityFlags.NewTask) && intent.Flags.HasFlag(ActivityFlags.ClearTask))
            {
                if (!this.activitiesShownWithNewAndClear.Contains(intent.Component.ClassName))
                {
                    this.activitiesShownWithNewAndClear.Add(intent.Component.ClassName);
                }
            }
        }
    }
}

This is my custom Presenter that works around the NewTask being added