MvvmCross: TextView binding inside ViewPager

Question

Can anyone please suggest binding for TextView inside ViewPager's fragment.

Please have look into below code for investigation.

ViewPager's fragment resource file (about_fragment.axml)

Here i'm trying to bind AboutDetail with ViewModel.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:background="@android:color/white">
    <TextView
        android:id="@+id/idAboutDetail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="32.5dp"
        android:layout_marginLeft="25dp"
        android:layout_marginRight="8dp"
        android:textColor="@android:color/black"
        android:textSize="17sp"      
local:MvxBind="Text AboutDetail"/>
</LinearLayout>

ViewPager's fragment VM

DetailViewModel belong to DetailFragment which contains ViewPager.

    [AddINotifyPropertyChangedInterface]
    public class AboutDetailViewModel : MvxViewModel<DetailViewModel>
    {
        public override void Prepare(DetailViewModel parameter)
        {
            AboutDetail = "Yes loaded";
        }

        private string _aboutDetail;
        public string AboutDetail
        {

            get
            {
                return _aboutDetail;
            }

            set
            {

                _aboutDetail = value;

                RaisePropertyChanged(() => AboutDetail);
            }

        }
    }

ViewPager's Fragment

public class UCAboutFragment :BaseFragment<AboutDetailViewModel>
{
    protected override int FragmentId => Resource.Layout.fragment_details_about;

    public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {

        View view = base.OnCreateView(inflater, container, savedInstanceState);

        return view;
    }

}

DetailFragment code which contains ViewPager.

DetailPagerAdapter pageAdapter = new DetailPagerAdapter(ChildFragmentManager);
            ViewPager pager = thisView.FindViewById<ViewPager>(Resource.Id.viewpager);

            pager.Adapter = pageAdapter;

            TabLayout tabLayout = thisView.FindViewById<TabLayout>(Resource.Id.tabs);
            tabLayout.SetupWithViewPager(pager);

DetailPagerAdapter

   private class DetailPagerAdapter : FragmentPagerAdapter
    {
        private List<Android.Support.V4.App.Fragment> mFragmentList;
        private List<string> mFragmentTitleList = new List<string>();

        public SectionsPagerAdapter(Android.Support.V4.App.FragmentManager fm) : base(fm)
        {
            this.mFragmentList = new List<Android.Support.V4.App.Fragment>();
            addFragment(new UCAboutFragment(), "About");
            addFragment(new UCServicesFragment(), "Services");
            addFragment(new UCInsuranceFragment(), "Insurance");


        }

        #region implemented abstract members of PagerAdapter
        public override int Count
        {
            get
            {
                return mFragmentList.Count;
            }
        }
        #endregion
        #region implemented abstract members of FragmentPagerAdapter
        public override Android.Support.V4.App.Fragment GetItem(int position)
        {
            return mFragmentList[position];
        }
        #endregion

        public override ICharSequence GetPageTitleFormatted(int position)
        {
            return new Java.Lang.String(mFragmentTitleList[position].ToLower());
        }

        private void addFragment(Android.Support.V4.App.Fragment fragment, string title)
        {
            mFragmentList.Add(fragment);
            mFragmentTitleList.Add(title);
        }
    }

BaseFragment

{
        public abstract class BaseFragment : MvxFragment
            {
                protected Toolbar Toolbar { get; private set; }
                protected BaseFragment()
                {
                    RetainInstance = true;
                }

                public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
                {
                    var ignore = base.OnCreateView(inflater, container, savedInstanceState);
                    var view = this.BindingInflate(FragmentId, null);

                    return view;
                 }

          protected abstract int FragmentId { get; }

        }

        public abstract class BaseFragment<TViewModel> : BaseFragment where TViewModel : class, IMvxViewModel
            {
                public new TViewModel ViewModel
                {
                    get { return (TViewModel)base.ViewModel; }
                    set { base.ViewModel = value; }
                }
            }
}

Answer 1

In the Fragments you have in your ViewPager, you need to use BindingInflate to inflate your View:

public class UCAboutFragment :BaseFragment<AboutDetailViewModel>
{
    protected override int FragmentId => Resource.Layout.fragment_details_about;

    public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        var _ = base.OnCreateView(inflater, container, savedInstanceState);

        var view = this.BindingInflate(FragmentId, container, false);
        return view;
    }
}

BindingInflate is what discovers the binding expressions in your layout and connects the ViewModel with the View iteself.