ITブログ時々なんでもブログ

１．PCLでの実装方法

//LogUtility.cs
public static class LogUtility
{
    /// <summary>
    /// 保存パス
    /// </summary>
    private static string _savePath = null;

    /// <summary>
    /// ログを出力する
    /// </summary>
    /// <param name="err">エラー内容</param>
    public static void OutPutError(string err)
    {
        //保存パスを形成する
        //保存パス＝ドキュメントパス＆アプリ名_yyyyMMdd.log
        if (String.IsNullOrEmpty(_savePath))
        {
            _savePath = Common.GetDocumentPath();
            if (!_savePath.EndsWith("/"))
            {
                _savePath += "/";
            }
            _savePath += Common.FileService.GetPackageName() + "_";
        }
        //ログ内容の成形
        string msg = "---------------------------------------------------------------------------------------------" + System.Environment.NewLine +
                     DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss") + " Error " + System.Environment.NewLine +
                     err;

        //Visual Studio 上でのログを出力する
        System.Diagnostics.Debug.WriteLine(msg);

        //ファイルログを出力する
        DependencyService.Get<IFileService>().OutPutLog(_savePath + DateTime.Now.ToString("yyyyMMdd") + ".log", msg);
    }    
}

//Common.cs
public static class Common
{
    /// <summary>
    /// ドキュメントディレクトリを取得する
    /// </summary>
    /// <returns></returns>
    public static string GetDocumentPath()
    {
        string path = DependencyService.Get<IFileService>().GetDocumentPath();
        if (String.IsNullOrEmpty(path))
        {
            path = DependencyService.Get<IFileService>().GetDownloadPath();
        }
        return path;
    }
}

//IFileService.cs
//DependencyServiceから利用する
public interface IFileService
{
    string GetPackageName();
    string GetDocumentPath();
    string GetDownloadPath();
    void OutPutLog(string path, string err);
}

２．Androidの実装方法

//Android  FileService.cs
using Android.Content;
using System;
using System.IO;
using Xamarin.Forms;
[assembly: Dependency(typeof(FileService))]
public class FileService : IFileService
{
    public string GetPackageName()
    {
        Context context = Forms.Context;
        var name = context.PackageManager.GetPackageInfo(context.PackageName, 0).PackageName;
        return name;
    }
    public string GetDocumentPath()
    {
        try
        {
            var dir = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDocuments);
            return dir.AbsolutePath;
        }
        catch
        {
            return String.Empty;
        }
    }
    public string GetDownloadPath()
    {
        try
        {
            var dir = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads);
            return dir.AbsolutePath;
        }
        catch
        {
            return String.Empty;
        }
    }
    public void OutPutLog(string path, string err)
    {
        //System.IOを利用する場合
        //System.IO.FileStream fs = new FileStream(path, FileMode.Append);
        //StreamWriter sw = new StreamWriter(fs);
        //sw.WriteLine(err);
        //sw.Close();
        //fs.Close();
        //sw = null;
        //fs = null;

        //こちらの方がNativeです。Java.IO
        Java.IO.FileWriter fw = new Java.IO.FileWriter(path, true);
        Java.IO.BufferedWriter bw = new Java.IO.BufferedWriter(fw);
        bw.Write(err);
        bw.NewLine();
        bw.Close();
        fw.Close();
        bw = null;
        fw= null;
    }
}

３．iOSの実装方法

//iOS FileService.cs
using System;
using System.IO;
using Foundation;
using Xamarin.Forms;
[assembly: Dependency(typeof(FileService))]
public class FileService : IFileService
{
    public string GetPackageName()
    {
        string name = NSBundle.MainBundle.InfoDictionary["CFBundleDisplayName"].ToString();
        return name.ToString();
    }
    public string GetDocumentPath()
    {
        return Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
    }
    public string GetDownloadPath()
    {
        return Environment.GetFolderPath(Environment.SpecialFolder.InternetCache);
    }
    public void OutPutLog(string path, string err)
    {
        System.IO.FileStream fs = new FileStream(path, FileMode.Append);
        StreamWriter sw = new StreamWriter(fs);
        sw.WriteLine(err);
        sw.Close();
        fs.Close();
        sw = null;
        fs = null;
    }
}

４．使用例

using AppName.Services;
using Xamarin.Forms;
public partial class TestPage : ContentPage
{
    void Test()
    {
        try
        {
            //省略
        }
        catch (Exception ex)
        {
            LogUtility.OutPutError(ex.Message + System.Environment.NewLine + ex.StackTrace);
        }
    }
}

５．実行例