如何更改导航页面中页眉的字体大小和粗细? [英] How can I change the Font Size and Weight for the Header in a Navigation Page?

问题描述

我可以这样更改Font Color:

var homePage = new NavigationPage(new HomePage())
{ 
   Title = "Home",
   Icon = "ionicons_2_0_1_home_outline_25.png",
   BarTextColor = Color.Gray,
};

但是有没有办法更改标题的Font Size和Weight?我只想在 iOS 和 Android 平台上进行更改.希望有人知道Custom Renderer代码可以帮助我做到这一点.

But is there a way to change the Font Size and Weight for the Title? I would like to change it for the iOS and Android platforms only. Hoping that someone knows of Custom Renderer code that can help me to do this.

请注意，这个问题与我有关如何更改已在此处回答的字体的问题类似:

Note that this question is similar to my question on how to change the Font which has been answered here:

推荐答案

这是Android的自定义渲染器，您可以在其中更改Font Size和Font Weight.我已经用TODO标记了必须更改的值.

Here is an Custom Renderer for Android where you are able to change the Font Size and also the Font Weight. I've marked the values you have to change with an TODO.

using Android.Content;
using Android.Graphics;
using App5.Droid;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android.AppCompat;

[assembly: ExportRenderer(typeof(NavigationPage), typeof(CustomNavigationPageRenderer))]
namespace App5.Droid
{
    public class CustomNavigationPageRenderer : NavigationPageRenderer
    {
        private Android.Support.V7.Widget.Toolbar _toolbar;

        public CustomNavigationPageRenderer(Context context) : base(context)
        {
        }

        public override void OnViewAdded(Android.Views.View child)
        {
            base.OnViewAdded(child);

            if (child.GetType() == typeof(Android.Support.V7.Widget.Toolbar))
            {
                _toolbar = (Android.Support.V7.Widget.Toolbar)child;
                _toolbar.ChildViewAdded += Toolbar_ChildViewAdded;
            }
        }

        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);

            if (disposing)
            {
                _toolbar.ChildViewAdded -= Toolbar_ChildViewAdded;
            }
        }

        private void Toolbar_ChildViewAdded(object sender, ChildViewAddedEventArgs e)
        {
            var view = e.Child.GetType();

            System.Diagnostics.Debug.WriteLine(view);

            if (e.Child.GetType() == typeof(Android.Support.V7.Widget.AppCompatTextView))
            {
                var textView = (Android.Support.V7.Widget.AppCompatTextView)e.Child;

                // TODO: CHANGE VALUES HERE
                textView.TextSize = 25;
                textView.SetTypeface(null, TypefaceStyle.Bold);

                _toolbar.ChildViewAdded -= Toolbar_ChildViewAdded;
            }
        }
    }
}

这是针对iOS的自定义渲染器的实现.

Here is an implementation of a Custom Renderer for iOS.

using App5.iOS;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer(typeof(NavigationPage), typeof(CustomNavigationPageRenderer))]
namespace App5.iOS
{
    public class CustomNavigationPageRenderer : NavigationRenderer
    {
        protected override void OnElementChanged(VisualElementChangedEventArgs e)
        {
            base.OnElementChanged(e);

            if (e.NewElement != null)
            {
                var att = new UITextAttributes();
                // TODO: Create your FontSize and FontWeight here
                var fontSize = Font.SystemFontOfSize(30.0);
                var boldFontSize = Font.SystemFontOfSize(35.0, FontAttributes.Bold);
                // TODO: Apply your selected FontSize and FontWeight combination here
                att.Font = boldFontSize.ToUIFont();
                UINavigationBar.Appearance.SetTitleTextAttributes(att);
            }
        }
    }
}

这篇关于如何更改导航页面中页眉的字体大小和粗细?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！