fix & improve importing comic

lib/utils/io.dart

@@ -14,6 +14,21 @@ import 'package:venera/utils/file_type.dart';
 export 'dart:io';
 export 'dart:typed_data';
 
+class IO {
+  /// A global flag used to indicate whether the app is selecting files.
+  ///
+  /// Select file and other similar file operations will launch external programs,
+  /// causing the app to lose focus. AppLifecycleState will be set to paused.
+  static bool get isSelectingFiles => _isSelectingFiles;
+
+  static bool _isSelectingFiles = false;
+}
+
+/// A finalizer that can be used to dispose resources related to file operations.
+final _finalizer = Finalizer<Function>((e) {
+  e();
+});
+
 class FilePath {
   const FilePath._();
 
@@ -147,24 +162,35 @@ String findValidDirectoryName(String path, String directory) {
 }
 
 class DirectoryPicker {
+  DirectoryPicker() {
+    _finalizer.attach(this, dispose);
+  }
+
   String? _directory;
 
   final _methodChannel = const MethodChannel("venera/method_channel");
 
   Future<Directory?> pickDirectory() async {
-    if (App.isWindows || App.isLinux) {
-      var d = await file_selector.getDirectoryPath();
-      _directory = d;
-      return d == null ? null : Directory(d);
-    } else if (App.isAndroid) {
-      var d = await _methodChannel.invokeMethod<String?>("getDirectoryPath");
-      _directory = d;
-      return d == null ? null : Directory(d);
-    } else {
-      // ios, macos
-      var d = await _methodChannel.invokeMethod<String?>("getDirectoryPath");
-      _directory = d;
-      return d == null ? null : Directory(d);
+    IO._isSelectingFiles = true;
+    try {
+      if (App.isWindows || App.isLinux) {
+        var d = await file_selector.getDirectoryPath();
+        _directory = d;
+        return d == null ? null : Directory(d);
+      } else if (App.isAndroid) {
+        var d = await _methodChannel.invokeMethod<String?>("getDirectoryPath");
+        _directory = d;
+        return d == null ? null : Directory(d);
+      } else {
+        // ios, macos
+        var d = await _methodChannel.invokeMethod<String?>("getDirectoryPath");
+        _directory = d;
+        return d == null ? null : Directory(d);
+      }
+    } finally {
+      Future.delayed(const Duration(milliseconds: 100), () {
+        IO._isSelectingFiles = false;
+      });
     }
   }
 
@@ -172,11 +198,15 @@ class DirectoryPicker {
     if (_directory == null) {
       return;
     }
-    if (App.isAndroid && _directory != null) {
-      return Directory(_directory!).deleteIgnoreError(recursive: true);
+    if (App.isAndroid &&
+        _directory != null &&
+        _directory!.startsWith(App.cachePath)) {
+      await Directory(_directory!).deleteIgnoreError(recursive: true);
+      _directory = null;
     }
     if (App.isIOS || App.isMacOS) {
       await _methodChannel.invokeMethod("stopAccessingSecurityScopedResource");
+      _directory = null;
     }
   }
 }
@@ -186,53 +216,73 @@ class IOSDirectoryPicker {
 
   // 调用 iOS 目录选择方法
   static Future<String?> selectDirectory() async {
+    IO._isSelectingFiles = true;
     try {
       final String? path = await _channel.invokeMethod('selectDirectory');
       return path;
     } catch (e) {
       // 返回报错信息
       return e.toString();
+    } finally {
+      Future.delayed(const Duration(milliseconds: 100), () {
+        IO._isSelectingFiles = false;
+      });
     }
   }
 }
 
 Future<file_selector.XFile?> selectFile({required List<String> ext}) async {
-  var extensions = App.isMacOS || App.isIOS ? null : ext;
-  if (App.isAndroid) {
-    for (var e in ext) {
-      var fileType = FileType.fromExtension(e);
-      if (fileType.mime == "application/octet-stream") {
-        extensions = null;
-        break;
-      }
-    }
-  }
-  file_selector.XTypeGroup typeGroup = file_selector.XTypeGroup(
-    label: 'files',
-    extensions: extensions,
-  );
-  file_selector.XFile? file;
-  if (extensions == null && App.isAndroid) {
-    const selectFileChannel = MethodChannel("venera/select_file");
-    var filePath = await selectFileChannel.invokeMethod("selectFile");
-    if (filePath == null) return null;
-    file = file_selector.XFile(filePath);
-  } else {
-    file = await file_selector.openFile(
-      acceptedTypeGroups: <file_selector.XTypeGroup>[typeGroup],
+  IO._isSelectingFiles = true;
+  try {
+    var extensions = App.isMacOS || App.isIOS ? null : ext;
+    file_selector.XTypeGroup typeGroup = file_selector.XTypeGroup(
+      label: 'files',
+      extensions: extensions,
     );
-    if (file == null) return null;
+    file_selector.XFile? file;
+    if (App.isAndroid) {
+      const selectFileChannel = MethodChannel("venera/select_file");
+      String mimeType = "*/*";
+      if(ext.length == 1) {
+        mimeType = FileType.fromExtension(ext[0]).mime;
+        if(mimeType == "application/octet-stream") {
+          mimeType = "*/*";
+        }
+      }
+      var filePath = await selectFileChannel.invokeMethod(
+        "selectFile",
+        mimeType,
+      );
+      if (filePath == null) return null;
+      file = _AndroidFileSelectResult(filePath);
+    } else {
+      file = await file_selector.openFile(
+        acceptedTypeGroups: <file_selector.XTypeGroup>[typeGroup],
+      );
+      if (file == null) return null;
+    }
+    if (!ext.contains(file.path.split(".").last)) {
+      App.rootContext.showMessage(message: "Invalid file type");
+      return null;
+    }
+    return file;
+  } finally {
+    Future.delayed(const Duration(milliseconds: 100), () {
+      IO._isSelectingFiles = false;
+    });
   }
-  if (!ext.contains(file.path.split(".").last)) {
-    App.rootContext.showMessage(message: "Invalid file type");
-    return null;
-  }
-  return file;
 }
 
 Future<String?> selectDirectory() async {
-  var path = await file_selector.getDirectoryPath();
-  return path;
+  IO._isSelectingFiles = true;
+  try {
+    var path = await file_selector.getDirectoryPath();
+    return path;
+  } finally {
+    Future.delayed(const Duration(milliseconds: 100), () {
+      IO._isSelectingFiles = false;
+    });
+  }
 }
 
 // selectDirectoryIOS
@@ -245,25 +295,32 @@ Future<void> saveFile(
   if (data == null && file == null) {
     throw Exception("data and file cannot be null at the same time");
   }
-  if (data != null) {
-    var cache = FilePath.join(App.cachePath, filename);
-    if (File(cache).existsSync()) {
-      File(cache).deleteSync();
+  IO._isSelectingFiles = true;
+  try {
+    if (data != null) {
+      var cache = FilePath.join(App.cachePath, filename);
+      if (File(cache).existsSync()) {
+        File(cache).deleteSync();
+      }
+      await File(cache).writeAsBytes(data);
+      file = File(cache);
     }
-    await File(cache).writeAsBytes(data);
-    file = File(cache);
-  }
-  if (App.isMobile) {
-    final params = SaveFileDialogParams(sourceFilePath: file!.path);
-    await FlutterFileDialog.saveFile(params: params);
-  } else {
-    final result = await file_selector.getSaveLocation(
-      suggestedName: filename,
-    );
-    if (result != null) {
-      var xFile = file_selector.XFile(file!.path);
-      await xFile.saveTo(result.path);
+    if (App.isMobile) {
+      final params = SaveFileDialogParams(sourceFilePath: file!.path);
+      await FlutterFileDialog.saveFile(params: params);
+    } else {
+      final result = await file_selector.getSaveLocation(
+        suggestedName: filename,
+      );
+      if (result != null) {
+        var xFile = file_selector.XFile(file!.path);
+        await xFile.saveTo(result.path);
+      }
     }
+  } finally {
+    Future.delayed(const Duration(milliseconds: 100), () {
+      IO._isSelectingFiles = false;
+    });
   }
 }
 
@@ -302,3 +359,16 @@ String bytesToReadableString(int bytes) {
     return "${(bytes / 1024 / 1024 / 1024).toStringAsFixed(2)} GB";
   }
 }
+
+class _AndroidFileSelectResult extends s.XFile {
+  _AndroidFileSelectResult(super.path) {
+    _finalizer.attach(this, dispose);
+  }
+
+  void dispose() {
+    print("dispose $path");
+    if (path.startsWith(App.cachePath)) {
+      File(path).deleteIgnoreError();
+    }
+  }
+}