Xamarin.Forms中DependencyService的使用

Xamarin.Forms中DependencyService的使用

在Xamarin.Forms中，我们经常会根据各个平台的特性特殊处理一些需求，比如：读取应用的版本号。

在此也以读取应用版本号为例，练习DependencyService用法：

创建IPlatformInfoService接口：

using System;
using System.Collections.Generic;
using System.Text;

namespace XFPractice.Service
{
    public interface IPlatformInfoService
    {

        /// <summary>
        /// 获取应用版本
        /// </summary>
        /// <returns></returns>
        string GetAppVersion();
        
    }
}

在Android创建ImpDroidService实现IPlatformInfoService接口：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Xamarin.Forms;
using XFPractice.Service;


[assembly: Dependency(typeof(XFPractice.Droid.ImpService.ImpDroidService))]
namespace XFPractice.Droid.ImpService
{
    public class ImpDroidService: IPlatformInfoService
    {
        public string GetAppVersion()
        {
            var context = Android.App.Application.Context;
            var packageInfo = context.PackageManager.GetPackageInfo(
                context.PackageName, PackageInfoFlags.Configurations);
            return packageInfo.VersionName;
        }
    }
}

在iOS创建ImpiOSService实现IPlatformInfoService接口：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Foundation;
using UIKit;
using Xamarin.Forms;
using XFPractice.Service;


[assembly: Dependency(typeof(XFPractice.iOS.ImpService.ImpiOSService))]
namespace XFPractice.iOS.ImpService
{
    public class ImpiOSService : IPlatformInfoService
    {
        public string GetAppVersion()
        {
            var version = NSBundle.MainBundle.ObjectForInfoDictionary("CFBundleVersion");
            return version.ToString();
        }
    }
}

使用：

 private readonly IPlatformInfoService _platformService;           
 
 _platformService = DependencyService.Get<IPlatformInfoService>();
            
 var AppVersion = _platformService.GetAppVersion();

这样我们就能读取到App的版本了。