Xamarin-MaterialSearchBar 2.2.0

More information and advanced examples:

Wiki

Basic example:

XML:

<tk.supernovaic.MaterialSearchBar.MaterialSearchBar
    style="@style/MaterialSearchBarLight"
    app:mt_speechMode="true"
    app:mt_hint="Custom hint"
    app:mt_maxSuggestionsCount="10"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/searchBar" />

C#:

public partial class YourClassActivity : AppCompatActivity, MaterialSearchBar.IOnSearchActionListener
{    
    private MaterialSearchBar MSearchBar { get; set; }

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        MSearchBar = FindViewById<MaterialSearchBar>(Resource.Id.searchBar);

        MSearchBar.SetOnSearchActionListener(this);

        MSearchBar.AddTextChangeListener(new MaterialSearchBarListener());
    }

    void MaterialSearchBar.IOnSearchActionListener.OnButtonClicked(int p0)
    {
        switch (p0)
        {
            case MaterialSearchBar.BUTTON_NAVIGATION:
                Drawer.OpenDrawer((int)GravityFlags.Left);
                break;
            case MaterialSearchBar.BUTTON_SPEECH:
                break;
            case MaterialSearchBar.BUTTON_BACK:
                MSearchBar.DisableSearch();
                break;
        }
    }
}

public partial class YourClassActivity
{
    private class MaterialSearchBarListener : Java.Lang.Object, ITextWatcher
    {
        public void AfterTextChanged(IEditable s)
        {

        }

        public void BeforeTextChanged(ICharSequence s, int start, int count, int after)
        {

        }

        public void OnTextChanged(ICharSequence s, int start, int before, int count)
        {

        }
    }
}