Add some logic to fix System.IO.Compression dll not found error.Two method grap from https://github.com/Pathoschild/SMAPI/blob/develop/src/SMAPI.Mods.SaveBackup/ModEntry.cs

GeneralMods/AdvancedSaveBackup/SaveBackup.cs

@@ -2,6 +2,7 @@ using System;
 using System.IO;
 using System.IO.Compression;
 using System.Linq;
+using System.Reflection;
 using Omegasis.SaveBackup.Framework;
 using StardewModdingAPI;
 using StardewModdingAPI.Events;
@@ -57,21 +58,108 @@ namespace Omegasis.SaveBackup
             this.BackupSaves(SaveBackup.NightlyBackupsPath);
         }
 
+        /// <summary>Recursively copy a directory or file.</summary>
+        /// <param name="source">The file or folder to copy.</param>
+        /// <param name="targetFolder">The folder to copy into.</param>
+        /// <param name="copyRoot">Whether to copy the root folder itself, or <c>false</c> to only copy its contents.</param>
+        /// <param name="filter">A filter which matches the files or directories to copy, or <c>null</c> to copy everything.</param>
+        /// <remarks>Derived from the SMAPI installer code.</remarks>
+        /// <returns>Returns whether any files were copied.</returns>
+        private bool RecursiveCopy(FileSystemInfo source, DirectoryInfo targetFolder, bool copyRoot = true)
+        {
+            if (!source.Exists)
+                return false;
+
+            bool anyCopied = false;
+
+            switch (source)
+            {
+                case FileInfo sourceFile:
+                    targetFolder.Create();
+                    sourceFile.CopyTo(Path.Combine(targetFolder.FullName, sourceFile.Name));
+                    anyCopied = true;
+                    break;
+
+                case DirectoryInfo sourceDir:
+                    DirectoryInfo targetSubfolder = copyRoot ? new DirectoryInfo(Path.Combine(targetFolder.FullName, sourceDir.Name)) : targetFolder;
+                    foreach (var entry in sourceDir.EnumerateFileSystemInfos())
+                        anyCopied = this.RecursiveCopy(entry, targetSubfolder) || anyCopied;
+                    break;
+
+                default:
+                    throw new NotSupportedException($"Unknown filesystem info type '{source.GetType().FullName}'.");
+            }
+
+            return anyCopied;
+        }
+
+        /// <summary>Create a zip using the .NET compression library.</summary>
+        /// <param name="sourcePath">The file or directory path to zip.</param>
+        /// <param name="destination">The destination file to create.</param>
+        /// <exception cref="NotSupportedException">The compression libraries aren't available on this system.</exception>
+        private void CompressUsingNetFramework(string sourcePath, FileInfo destination)
+        {
+            // get compress method
+            MethodInfo createFromDirectory;
+            try
+            {
+                // create compressed backup
+                Assembly coreAssembly = Assembly.Load("System.IO.Compression, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089") ?? throw new InvalidOperationException("Can't load System.IO.Compression assembly.");
+                Assembly fsAssembly = Assembly.Load("System.IO.Compression.FileSystem, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089") ?? throw new InvalidOperationException("Can't load System.IO.Compression assembly.");
+                Type compressionLevelType = coreAssembly.GetType("System.IO.Compression.CompressionLevel") ?? throw new InvalidOperationException("Can't load CompressionLevel type.");
+                Type zipFileType = fsAssembly.GetType("System.IO.Compression.ZipFile") ?? throw new InvalidOperationException("Can't load ZipFile type.");
+                createFromDirectory = zipFileType.GetMethod("CreateFromDirectory", new[] { typeof(string), typeof(string), compressionLevelType, typeof(bool) }) ?? throw new InvalidOperationException("Can't load ZipFile.CreateFromDirectory method.");
+            }
+            catch (Exception ex)
+            {
+                throw new NotSupportedException("Couldn't load the .NET compression libraries on this system.", ex);
+            }
+
+            // compress file
+            createFromDirectory.Invoke(null, new object[] { sourcePath, destination.FullName, CompressionLevel.Fastest, false });
+        }
+
+        private void OriginCompressLogic(string folderPath)
+        {
+            ZipFile.CreateFromDirectory(SaveBackup.SavesPath, Path.Combine(folderPath, $"backup-{DateTime.Now:yyyyMMdd'-'HHmmss}.zip"));
+        }
+
         /// <summary>Back up saves to the specified folder.</summary>
         /// <param name="folderPath">The folder path in which to generate saves.</param>
         private void BackupSaves(string folderPath)
         {
             // back up saves
             Directory.CreateDirectory(folderPath);
-            ZipFile.CreateFromDirectory(SaveBackup.SavesPath, Path.Combine(folderPath, $"backup-{DateTime.Now:yyyyMMdd'-'HHmmss}.zip"));
+            if(Constants.TargetPlatform == GamePlatform.Android)
+            {
+                FileInfo targetFile = new FileInfo(Path.Combine(folderPath, $"backup-{DateTime.Now:yyyyMMdd'-'HHmmss}.zip"));
+                try
+                {
+                    this.CompressUsingNetFramework(folderPath, targetFile);
+                }
+                catch (NotSupportedException)
+                {
+                    this.RecursiveCopy(new DirectoryInfo(SaveBackup.SavesPath), new DirectoryInfo(Path.Combine(folderPath, $"backup-{DateTime.Now:yyyyMMdd'-'HHmmss}")), false);
+                }
+            }
+            else
+            {
+                this.OriginCompressLogic(folderPath);
+            }
 
             // delete old backups
             new DirectoryInfo(folderPath)
-                .EnumerateFiles()
+                .GetFileSystemInfos()
                 .OrderByDescending(f => f.CreationTime)
                 .Skip(this.Config.SaveCount)
                 .ToList()
-                .ForEach(file => file.Delete());
+                .ForEach(file =>
+                {
+                    if (file is DirectoryInfo folder)
+                        folder.Delete(recursive: true);
+                    else
+                        file.Delete();
+                });
         }
     }
 }