saveFile method implemented for android platform

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 6.1.0
+### Android
+- saveFile() method implemented for the android platform
 ## 6.0.0
 Update minimum Flutter version to 3.7.0.
 

android/src/main/java/com/mr/flutter/plugin/filepicker/FileInfo.java

@@ -20,6 +20,10 @@ public FileInfo(String path, String name, Uri uri, long size, byte[] bytes) {
         this.uri = uri;
     }
 
+    public String toString() {
+        return "path: " + this.path + ", name: " + this.name;
+    }
+
     public static class Builder {
 
         private String path;

android/src/main/java/com/mr/flutter/plugin/filepicker/FilePickerDelegate.java

@@ -37,6 +37,7 @@ public class FilePickerDelegate implements PluginRegistry.ActivityResultListener
     private boolean isMultipleSelection = false;
     private boolean loadDataToMemory = false;
     private String type;
+    private String input;
     private String[] allowedExtensions;
     private EventChannel.EventSink eventSink;
 
@@ -119,16 +120,26 @@ public void run() {
                                     finishWithError("unknown_path", "Failed to retrieve directory path.");
                                 }
                                 return;
+                            } else if (type.equals("save") && Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+                                Log.d(FilePickerDelegate.TAG, "[SaveFile] File URI:" + uri.toString());
+                                final String filePath = FileUtils.getAbsolutePathFromUri(uri, input, activity);
+                                if(filePath != null) {
+                                    Log.d(FilePickerDelegate.TAG, "[SaveFile] File Path:" + filePath);
+                                    finishWithSuccess(filePath);
+                                } else {
+                                    finishWithError("unknown_path", "Failed to retrieve file path.");
+                                }
+                                return;
                             }
 
                             final FileInfo file = FileUtils.openFileStream(FilePickerDelegate.this.activity, uri, loadDataToMemory);
 
                             if(file != null) {
+                                Log.d(FilePickerDelegate.TAG, file.toString());
                                 files.add(file);
                             }
 
                             if (!files.isEmpty()) {
-                                Log.d(FilePickerDelegate.TAG, "File path:" + files.toString());
                                 finishWithSuccess(files);
                             } else {
                                 finishWithError("unknown_path", "Failed to retrieve path.");
@@ -229,6 +240,14 @@ private void startFileExplorer() {
 
         if (type.equals("dir")) {
             intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);
+        } else if (type.equals("save")) {
+            intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
+            intent.addCategory(Intent.CATEGORY_OPENABLE);
+            Log.d(TAG, "Selected type " + type);
+            intent.setType("*/*");
+            if (allowedExtensions != null) {
+                intent.putExtra(Intent.EXTRA_MIME_TYPES, allowedExtensions);
+            }
         } else {
             if (type.equals("image/*")) {
                 intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
@@ -261,14 +280,15 @@ private void startFileExplorer() {
     }
 
     @SuppressWarnings("deprecation")
-    public void startFileExplorer(final String type, final boolean isMultipleSelection, final boolean withData, final String[] allowedExtensions, final MethodChannel.Result result) {
+    public void startFileExplorer(final String type, final String input, final boolean isMultipleSelection, final boolean withData, final String[] allowedExtensions, final MethodChannel.Result result) {
 
         if (!this.setPendingMethodCallAndResult(result)) {
             finishWithAlreadyActiveError(result);
             return;
         }
 
         this.type = type;
+        this.input = input;
         this.isMultipleSelection = isMultipleSelection;
         this.loadDataToMemory = withData;
         this.allowedExtensions = allowedExtensions;

android/src/main/java/com/mr/flutter/plugin/filepicker/FilePickerPlugin.java

@@ -111,6 +111,7 @@ public void onActivityStopped(final Activity activity) {
     private Activity activity;
     private MethodChannel channel;
     private static String fileType;
+    private static String inputFile;
     private static boolean isMultipleSelection = false;
     private static boolean withData = false;
 
@@ -159,6 +160,9 @@ public void onMethodCall(final MethodCall call, final MethodChannel.Result rawRe
 
         if (fileType == null) {
             result.notImplemented();
+        } else if (fileType == "save") {
+            inputFile         = (String) arguments.get("inputFile");
+            allowedExtensions = FileUtils.getMimeTypes((ArrayList<String>) arguments.get("allowedExtensions"));
         } else if (fileType != "dir") {
             isMultipleSelection = (boolean) arguments.get("allowMultipleSelection");
             withData = (boolean) arguments.get("withData");
@@ -168,7 +172,7 @@ public void onMethodCall(final MethodCall call, final MethodChannel.Result rawRe
         if (call.method != null && call.method.equals("custom") && (allowedExtensions == null || allowedExtensions.length == 0)) {
             result.error(TAG, "Unsupported filter. Make sure that you are only using the extension without the dot, (ie., jpg instead of .jpg). This could also have happened because you are using an unsupported file extension.  If the problem persists, you may want to consider using FileType.all instead.", null);
         } else {
-            this.delegate.startFileExplorer(fileType, isMultipleSelection, withData, allowedExtensions, result);
+            this.delegate.startFileExplorer(fileType, inputFile, isMultipleSelection, withData, allowedExtensions, result);
         }
 
     }
@@ -189,6 +193,9 @@ private static String resolveType(final String type) {
                 return "*/*";
             case "dir":
                 return "dir";
+            case "save":
+                return "save";
+
             default:
                 return null;
         }

android/src/main/java/com/mr/flutter/plugin/filepicker/FileUtils.java

@@ -7,11 +7,13 @@
 import android.net.Uri;
 import android.os.Build;
 import android.os.Environment;
+import android.os.storage.StorageVolume;
 import android.os.storage.StorageManager;
 import android.provider.DocumentsContract;
 import android.provider.OpenableColumns;
 import android.util.Log;
 import android.webkit.MimeTypeMap;
+import java.util.List;
 
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
@@ -24,6 +26,7 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.lang.reflect.Array;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
@@ -178,6 +181,60 @@ public static FileInfo openFileStream(final Context context, final Uri uri, bool
         return fileInfo.build();
     }
 
+    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
+    @Nullable
+    @SuppressWarnings("deprecation")
+    public static String getAbsolutePathFromUri(Uri uri, String input, Context context) {
+        String absolutePath = null;
+        if (DocumentsContract.isDocumentUri(context, uri)) {
+
+            // DocumentProvider
+            String documentId = DocumentsContract.getDocumentId(uri);
+            String[] split = documentId.split(":");
+            String authority = split[0];
+            String path = split[1];
+
+            try {
+                StorageManager storageManager =
+                    (StorageManager) context.getSystemService(Context.STORAGE_SERVICE);
+                StorageVolume storageVolume = null;
+                List<StorageVolume> storageVolumes = storageManager.getStorageVolumes();
+                for (StorageVolume volume : storageVolumes) {
+                    if (
+                        PRIMARY_VOLUME_NAME.equals(authority) ||
+                        (volume.getUuid() != null && volume.getUuid().equals(authority))
+                        ) {
+                        storageVolume = volume;
+                        break;
+                    }
+                }
+
+                if (storageVolume != null) {
+                    String rootPath = storageVolume.getDirectory().getAbsolutePath();
+                    absolutePath = rootPath + "/" + path;
+                    try {
+                        File iFile = new File(input);
+                        if (iFile.exists() && iFile.isFile()) {
+                            OutputStream outputStream = context.getContentResolver().openOutputStream(uri);
+                            InputStream inputStream = new FileInputStream(input);
+                            byte[] buffer = new byte[1024];
+                            int bytesRead = 0;
+                            while ((bytesRead = inputStream.read(buffer)) != -1) {
+                                outputStream.write(buffer, 0, bytesRead);
+                            }
+                        }
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
+                }
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+
+        return absolutePath;
+    }
+
     @RequiresApi(api = Build.VERSION_CODES.KITKAT)
     @Nullable
     @SuppressWarnings("deprecation")
@@ -307,4 +364,4 @@ private static String getDocumentPathFromTreeUri(final Uri treeUri) {
         else return File.separator;
     }
 
-}
+}

lib/src/file_picker_io.dart

@@ -42,6 +42,21 @@ class FilePickerIO extends FilePicker {
         withReadStream,
       );
 
+  @override
+  Future<String?> saveFile({
+    String? dialogTitle,
+    String? fileName,
+    String? initialDirectory,
+    FileType type = FileType.any,
+    List<String>? allowedExtensions,
+    bool lockParentWindow = false,
+  }) =>
+      _getSavePath(
+        fileName!,
+        type,
+        allowedExtensions,
+      );
+
   @override
   Future<bool?> clearTemporaryFiles() async =>
       _channel.invokeMethod<bool>('clear');
@@ -122,4 +137,32 @@ class FilePickerIO extends FilePicker {
       rethrow;
     }
   }
+
+  Future<String?> _getSavePath(
+    String inputFile,
+    FileType fileType,
+    List<String>? allowedExtensions,
+  ) async {
+    final String type = fileType.name;
+    if (type != 'custom' && (allowedExtensions?.isNotEmpty ?? false)) {
+      throw Exception(
+          'You are setting a type [$fileType]. Custom extension filters are only allowed with FileType.custom, please change it or remove filters.');
+    }
+    try {
+      return await _channel.invokeMethod('save', {
+        'inputFile': inputFile,
+        'allowedExtensions': allowedExtensions,
+      });
+    } on PlatformException catch (e) {
+      if (e.code == "unknown_path") {
+        print(
+            '[$_tag] Could not resolve directory path. Maybe it\'s a protected one or unsupported (such as Downloads folder). If you are on Android, make sure that you are on SDK 21 or above.');
+      }
+      print('[$_tag] Platform exception: $e');
+    } catch (e) {
+      print(
+          '[$_tag] Unsupported operation. Method not found. The exception thrown was: $e');
+    }
+    return null;
+  }
 }

pubspec.yaml

@@ -3,7 +3,7 @@ description: A package that allows you to use a native file explorer to pick sin
 homepage: https://github.com/miguelpruivo/plugins_flutter_file_picker
 repository: https://github.com/miguelpruivo/flutter_file_picker
 issue_tracker: https://github.com/miguelpruivo/flutter_file_picker/issues
-version: 6.0.0
+version: 6.1.0
 
 dependencies:
   flutter: