Xamarin.Forms Android 底部導航欄

在Android中常見設計底部導航欄，在Xamarin.Forms中如何實現該效果呢？

這里借助第三方框架來實現底部導航效果：

第三方庫：Naxam.BottomTabbedPage

GitHub地址：https://github.com/naxam/bottomtabbedpage-xamarin-forms

 

首先：創建MainTabAndroidPage繼承於BottomTabbedPage

using Naxam.Controls.Forms;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace XFPractice.Pages.MainTab
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class MainTabAndroidPage : BottomTabbedPage
    {
        public MainTabAndroidPage()
        {
            InitializeComponent();
            NavigationPage.SetHasNavigationBar(this, true);
            NavigationPage.SetHasBackButton(this,false);
            InitTabPages();

            this.Appearing += MainTabAndroidPage_Appearing;
            this.CurrentPageChanged += MainTabAndroidPage_CurrentPageChanged;
        }

        private void MainTabAndroidPage_Appearing(object sender, EventArgs e)
        {
            UpdateNavigationBar();
        }

        private void MainTabAndroidPage_CurrentPageChanged(object sender, System.EventArgs e)
        {
            UpdateNavigationBar();
        }

        private void UpdateNavigationBar()
        {
            Title = CurrentPage.Title;
        }

        private void InitTabPages()
        {
            this.Children.Add(new MessagePage() { Title = "消息", Icon = "icon_chat" });
            this.Children.Add(new ContactsPage() { Title = "通訊錄", Icon = "icon_org" });
            this.Children.Add(new WorkStagePage() { Title = "工作台", Icon = "icon_table" });
            this.Children.Add(new ProfilePage() { Title = "我", Icon = "icon_me" });
        }


    }
}

Xaml代碼：

<?xml version="1.0" encoding="utf-8" ?>
<naxam:BottomTabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:naxam="clr-namespace:Naxam.BottomNavs.Forms;assembly=Naxam.BottomNavs.Forms"
             x:Class="XFPractice.Pages.MainTab.MainTabAndroidPage">
   
</naxam:BottomTabbedPage>

僅僅是以上代碼還不足以達到我們期望的效果，還需要在MainActivity中添加如下代碼，並在OnCreate中調用：

void SetupBottomTabs()
        {
            var stateList = new Android.Content.Res.ColorStateList(
                new int[][] {
                    new int[] { Android.Resource.Attribute.StateChecked
                },
                new int[] { Android.Resource.Attribute.StateEnabled
                }
                },
                new int[] {
                    Color.Red, //Selected
                    Color.White //Normal
                });
            
            BottomTabbedRenderer.BackgroundColor = new Color(0x9C, 0x27, 0xB0);
            BottomTabbedRenderer.FontSize = 10f;
            BottomTabbedRenderer.IconSize = 24;
            BottomTabbedRenderer.ItemTextColor = stateList;
            BottomTabbedRenderer.ItemIconTintList = stateList;
            //BottomTabbedRenderer.Typeface = Typeface.CreateFromAsset(this.Assets, "architep.ttf");
            //BottomTabbedRenderer.ItemBackgroundResource = Resource.Drawable.bnv_selector;
            BottomTabbedRenderer.ItemSpacing = 4;
            //BottomTabbedRenderer.ItemPadding = new Xamarin.Forms.Thickness(6);
            BottomTabbedRenderer.BottomBarHeight = 56;
            BottomTabbedRenderer.ItemAlign = ItemAlignFlags.Center;
            BottomTabbedRenderer.ShouldUpdateSelectedIcon = true;
            
            BottomTabbedRenderer.MenuItemIconSetter = (menuItem, iconSource, selected) => {
                var iconized = Iconize.FindIconForKey(iconSource.File);
                if (iconized == null)
                {
                    if (selected == true)
                        iconSource = iconSource + "_sel";
                    BottomTabbedRenderer.DefaultMenuItemIconSetter.Invoke(menuItem, iconSource, selected);
                    return;
                }
                var drawable = new IconDrawable(this, iconized).Color(selected ? Color.Red : Color.White).SizeDp(30);
                menuItem.SetIcon(drawable);

            };

        }

資源文件：

如此即可實現Android底部導航欄了。

在Xamarin.Forms 3.0中，由於Xamarin.Forms的一個bug，會導致頁面在pop后導致崩潰，解決方案：http://www.cnblogs.com/devin_zhou/p/9028214.html