修改UITabBar样式TintColor 和 Selected Tab Images in Xamarin.Forms iOS
如何在Xamarin.Forms中修改UITabBar样式?
首先新建MainTabbediOSPage继承于TabbedPage。
默认样式如下:
1. TintColor
想要得到如下效果:
只需在iOS项目中,AppDelegate 中的 FinishedLaunching 方法内添加如下代码:
1 UITabBar.Appearance.SelectedImageTintColor = UIColor.FromRGB(118,53,235);
2. Selected Tab Images
如果想要在Tab切换时,修改 Tab Image需要用到自定义渲染。
期望效果:
首先在iOS项目中Resource文件夹下添加Tab Images的资源文件:
(说明:此处如icon_chat是未选中图片资源,icon_chat_sel是选中图片资源)
Custom Renderer代码如下:
1 using System; 2 using System.Collections.Generic; 3 using System.Diagnostics; 4 using System.Linq; 5 using System.Text; 6 7 using Foundation; 8 using UIKit; 9 using Xamarin.Forms;10 using Xamarin.Forms.Platform.iOS;11 using XFPractice.iOS.Renderer;12 using XFPractice.Pages;13 14 [assembly: ExportRenderer(typeof(MainTabbediOSPage), typeof(MyTabPageRenderer))]15 namespace XFPractice.iOS.Renderer16 {17 18 public class MyTabPageRenderer: TabbedRenderer19 {20 public override void ViewWillAppear(bool animated)21 {22 if (TabBar?.Items == null)23 return;24 25 if (Element is TabbedPage tabs)26 {27 for (int i = 0; i < TabBar.Items.Length; i++)28 {29 UpdateItem(TabBar.Items[i], tabs.Children[i].Icon);30 }31 }32 base.ViewWillAppear(animated);33 }34 35 void UpdateItem(UITabBarItem item, string icon)36 {37 if (item == null)38 return;39 try40 {41 icon = icon + "_sel";42 if (item?.SelectedImage?.AccessibilityIdentifier == icon)43 return;44 item.SelectedImage = UIImage.FromBundle(icon);45 item.SelectedImage.AccessibilityIdentifier = icon;46 }47 catch (Exception ex)48 {49 Console.WriteLine("Unable to set selected icon: " + ex);50 }51 52 }53 }54 }