fix importing data on Android

android/app/src/main/kotlin/com/github/wgh136/venera/MainActivity.kt

@@ -10,7 +10,6 @@ import android.view.KeyEvent
 import android.Manifest
 import android.os.Environment
 import android.provider.Settings
-import androidx.annotation.RequiresApi
 import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import androidx.documentfile.provider.DocumentFile
@@ -34,6 +33,8 @@ class MainActivity : FlutterActivity() {
     private val storageRequestCode = 0x10
     private var storagePermissionRequest: ((Boolean) -> Unit)? = null
 
+    private val selectFileCode = 0x11
+
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
         super.onActivityResult(requestCode, resultCode, data)
         if (requestCode == pickDirectoryCode) {
@@ -59,6 +60,41 @@ class MainActivity : FlutterActivity() {
                 storagePermissionRequest?.invoke(Environment.isExternalStorageManager())
             }
             storagePermissionRequest = null
+        } else if (requestCode == selectFileCode) {
+            if (resultCode != Activity.RESULT_OK) {
+                result.success(null)
+                return
+            }
+            val uri = data?.data
+            if (uri == null) {
+                result.success(null)
+                return
+            }
+            val contentResolver = context.contentResolver
+            val file = DocumentFile.fromSingleUri(context, uri)
+            if (file == null) {
+                result.success(null)
+                return
+            }
+            val fileName = file.name
+            if (fileName == null) {
+                result.success(null)
+                return
+            }
+            // copy file to cache directory
+            val cacheDir = context.cacheDir
+            val newFile = File(cacheDir, fileName)
+            val inputStream = contentResolver.openInputStream(uri)
+            if (inputStream == null) {
+                result.success(null)
+                return
+            }
+            val outputStream = FileOutputStream(newFile)
+            inputStream.copyTo(outputStream)
+            inputStream.close()
+            outputStream.close()
+            // send file path to flutter
+            result.success(newFile.absolutePath)
         }
     }
 
@@ -112,6 +148,12 @@ class MainActivity : FlutterActivity() {
                 res.success(result)
             }
         }
+
+        val selectFileChannel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "venera/select_file")
+        selectFileChannel.setMethodCallHandler { _, res ->
+            openFile()
+            result = res
+        }
     }
 
     private fun getProxy(): String {
@@ -223,6 +265,13 @@ class MainActivity : FlutterActivity() {
             storagePermissionRequest = null
         }
     }
+
+    fun openFile() {
+        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
+        intent.addCategory(Intent.CATEGORY_OPENABLE)
+        intent.type = "*/*"
+        startActivityForResult(intent, selectFileCode)
+    }
 }
 
 class VolumeListen{

lib/utils/file_type.dart

@@ -1,5 +1,3 @@
-import 'dart:typed_data';
-
 import 'package:mime/mime.dart';
 
 class FileType {
@@ -7,6 +5,14 @@ class FileType {
   final String mime;
 
   const FileType(this.ext, this.mime);
+
+  static FileType fromExtension(String ext) {
+    if(ext.startsWith('.')) {
+      ext = ext.substring(1);
+    }
+    var mime = lookupMimeType('no-file.$ext');
+    return FileType(".$ext", mime ?? 'application/octet-stream');
+  }
 }
 
 FileType detectFileType(List<int> data) {

lib/utils/io.dart

@@ -9,6 +9,7 @@ import 'package:venera/utils/ext.dart';
 import 'package:path/path.dart' as p;
 import 'package:share_plus/share_plus.dart' as s;
 import 'package:file_selector/file_selector.dart' as file_selector;
+import 'package:venera/utils/file_type.dart';
 
 export 'dart:io';
 export 'dart:typed_data';
@@ -86,7 +87,7 @@ extension DirectoryExtension on Directory {
 }
 
 String sanitizeFileName(String fileName) {
-  if(fileName.endsWith('.')) {
+  if (fileName.endsWith('.')) {
     fileName = fileName.substring(0, fileName.length - 1);
   }
   const maxLength = 255;
@@ -126,7 +127,8 @@ Future<void> copyDirectory(Directory source, Directory destination) async {
   }
 }
 
-Future<void> copyDirectoryIsolate(Directory source, Directory destination) async {
+Future<void> copyDirectoryIsolate(
+    Directory source, Directory destination) async {
   await Isolate.run(() {
     copyDirectory(source, destination);
   });
@@ -196,14 +198,32 @@ class IOSDirectoryPicker {
 }
 
 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: App.isMacOS || App.isIOS ? null : ext,
+    extensions: extensions,
   );
-  final file_selector.XFile? file = await file_selector.openFile(
+  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],
     );
     if (file == null) return null;
+  }
   if (!ext.contains(file.path.split(".").last)) {
     App.rootContext.showMessage(message: "Invalid file type");
     return null;