How change color of three btn at toolbar crossplatform

Question

I could not understand why the button with dots is not displayed. But clicking in this area opens drop-down menus.

The dots on the button are white and they just blend in with the background. I found a solution for android, but how do I go about making a cross platform solution to the problem?

<ContentPage.ToolbarItems>
    <ToolbarItem 
        Order="Secondary"
        
        Text="Item 0"
        Priority="0"/>
    <ToolbarItem 
        Order="Secondary"
        Text="Item 1"
        Priority="1"/>
    <ToolbarItem 
        Order="Secondary"
        Text="Item 2"
        Priority="2"/>
</ContentPage.ToolbarItems>

Answer 1

in file style.xml find MainTheme and add

<item name="android:textColorSecondary">#592bca</item> 

then in file Toolbar.axml add or change

android:theme="@style/MainTheme"
android:popupTheme="@style/MainTheme.Base" 

Answer 2

When the Order property is set to Secondary, behavior varies across platforms. On UWP and Android, the Secondary items menu appears as three dots that can be tapped or clicked to reveal items in a vertical list. On iOS, the Secondary items menu appears below the navigation bar as a horizontal list.

A easy is to change the background color of the toolbar.

App.xaml.cs:

 var navPage = new NavigationPage(new Page2());
        this.MainPage = navPage;

        navPage.BarBackgroundColor = Color.Blue;

Update:

Android:

Change the color of 3 dots in style:

  <style name="MainTheme" parent="MainTheme.Base">  
<item name="android:textColorSecondary">#54FF9F</item> 
</style>

Use the androidx.appcompat.widget.Toolbar in the Toolbar.xml:

  <?xml version="1.0" encoding="utf-8"?>
 <androidx.appcompat.widget.Toolbar
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto" 
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@android:color/white"
android:theme="@style/MainTheme"
android:popupTheme="@style/MainTheme.Base" 
 />

iOS:

Like what i said in previouss reply, the Secondary items menu on ios appears below the navigation bar as a horizontal list.

You could use IOSToolbarExtensions instead.

NuGet: https://www.nuget.org/packages/IOSToolbarExtensions/

Install it and add the code below into AssemblyInfo.cs:

[assembly: ExportRenderer(typeof(ContentPage), typeof(IOSToolbarExtensions.iOS.Renderers.IOSToolbarExtensionsContentPageRenderer), Priority = short.MaxValue)]