bookmark: use Storage Access Framework to export bookmarks

android/app/src/main/kotlin/xyz/project/violet/MainActivity.kt

@@ -1,5 +1,7 @@
 package xyz.project.violet
 
+import android.app.Activity
+import android.content.Intent
 import android.os.Build
 import android.os.Bundle
 import android.os.Environment
@@ -13,6 +15,8 @@ import io.flutter.plugin.common.MethodCall
 import io.flutter.plugin.common.MethodChannel
 import io.flutter.plugin.common.MethodChannel.MethodCallHandler
 import io.flutter.plugins.GeneratedPluginRegistrant
+import java.io.FileInputStream
+import java.io.FileOutputStream
 
 class MainActivity : FlutterFragmentActivity() {
     private val VOLUME_CHANNEL = "xyz.project.violet/volume"
@@ -82,6 +86,7 @@ class MainActivity : FlutterFragmentActivity() {
         MethodChannel(flutterEngine.dartExecutor.binaryMessenger, MISC_CHANNEL).setMethodCallHandler { call, result ->
             when (call.method) {
                 "finishMainActivity" -> finishMainActivity(call, result)
+                "exportFile" -> exportFile(call, result)
                 else -> result.notImplemented()
             }
         }
@@ -100,4 +105,80 @@ class MainActivity : FlutterFragmentActivity() {
         finish()
         result.success(null)
     }
+
+    private class ExportFileRequest(
+        val filePath: String,
+        val call: MethodCall,
+        val result: MethodChannel.Result,
+    )
+
+    private var nextExportFileRequestCode = 1000001;
+    private val exportFileRequestMap = hashMapOf<Int, ExportFileRequest>()
+
+    private fun exportFile(call: MethodCall, result: MethodChannel.Result) {
+        val filePath = call.argument<String>("filePath")
+        val mimeType = call.argument<String>("mimeType")
+        val fileNameToSaveAs = call.argument<String>("fileNameToSaveAs")
+
+        if (filePath == null) {
+            result.error("noArgument", "filePath", null)
+            return
+        }
+
+        if (mimeType == null) {
+            result.error("noArgument", "mimeType", null)
+            return
+        }
+
+        if (fileNameToSaveAs == null) {
+            result.error("noArgument", "fileNameToSaveAs", null)
+            return
+        }
+
+        try {
+            val intent = Intent(Intent.ACTION_CREATE_DOCUMENT).apply {
+                addCategory(Intent.CATEGORY_OPENABLE)
+                type = mimeType
+                putExtra(Intent.EXTRA_TITLE, fileNameToSaveAs)
+            }
+
+            exportFileRequestMap[nextExportFileRequestCode] =
+                ExportFileRequest(filePath, call, result)
+            startActivityForResult(intent, nextExportFileRequestCode++);
+        } catch (e: Throwable) {
+            result.error("exception", e.toString(), e);
+        }
+    }
+
+    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
+        super.onActivityResult(requestCode, resultCode, data)
+
+        val request = exportFileRequestMap[requestCode] ?: return
+
+        try {
+            if (resultCode != Activity.RESULT_OK) {
+                request.result.error("intentResultFail", "resultCode=$resultCode", null)
+                return
+            }
+
+            try {
+                val uri = data!!.data!!
+                val targetFileDescriptor = contentResolver.openFileDescriptor(uri, "w")
+
+                val input = FileInputStream(request.filePath)
+                val output = FileOutputStream(targetFileDescriptor!!.fileDescriptor)
+
+                input.copyTo(output)
+
+                input.close()
+                output.close()
+
+                request.result.success(null)
+            } catch (e: Throwable) {
+                request.result.error("exception", e.toString(), e);
+            }
+        } finally {
+            exportFileRequestMap.remove(requestCode)
+        }
+    }
 }

lib/pages/settings/settings_page.dart

@@ -60,6 +60,7 @@ import 'package:violet/pages/settings/tag_rebuild_page.dart';
 import 'package:violet/pages/settings/tag_selector.dart';
 import 'package:violet/pages/settings/version_page.dart';
 import 'package:violet/pages/splash/splash_page.dart';
+import 'package:violet/platform/misc.dart';
 import 'package:violet/server/violet.dart';
 import 'package:violet/settings/settings.dart';
 import 'package:violet/style/palette.dart';
@@ -1994,36 +1995,45 @@ class _SettingsPageState extends State<SettingsPage>
             title: Text(Translations.of(context).trans('exportingbookmark')),
             trailing: const Icon(Icons.keyboard_arrow_right),
             onTap: () async {
-              if (!await Permission.storage.isGranted) {
-                if (await Permission.storage.request() ==
-                    PermissionStatus.denied) {
-                  flutterToast.showToast(
-                    child: ToastWrapper(
-                      isCheck: false,
-                      msg: Translations.of(context).trans('noauth'),
-                    ),
-                    gravity: ToastGravity.BOTTOM,
-                    toastDuration: const Duration(seconds: 4),
-                  );
+              final dir = Platform.isIOS
+                  ? await getApplicationSupportDirectory()
+                  : (await getApplicationDocumentsDirectory());
+              final bookmarkDatabaseFile = File('${dir.path}/user.db');
 
-                  return;
-                }
-              }
+              if (Platform.isAndroid) {
+                await PlatformMiscMethods.instance.exportFile(
+                  bookmarkDatabaseFile.path,
+                  mimeType: 'application/vnd.sqlite3',
+                  fileNameToSaveAs: 'violet-bookmarks.db',
+                );
+              } else {
+                if (!await Permission.storage.isGranted) {
+                  if (await Permission.storage.request() ==
+                      PermissionStatus.denied) {
+                    flutterToast.showToast(
+                      child: ToastWrapper(
+                        isCheck: false,
+                        msg: Translations.of(context).trans('noauth'),
+                      ),
+                      gravity: ToastGravity.BOTTOM,
+                      toastDuration: const Duration(seconds: 4),
+                    );
 
-              final selectedPath = await FilePicker.platform.getDirectoryPath();
+                    return;
+                  }
+                }
 
-              if (selectedPath == null) {
-                return;
-              }
+                final selectedPath =
+                    await FilePicker.platform.getDirectoryPath();
 
-              final db = Platform.isIOS
-                  ? await getApplicationSupportDirectory()
-                  : (await getApplicationDocumentsDirectory());
-              final dbfile = File('${db.path}/user.db');
+                if (selectedPath == null) {
+                  return;
+                }
 
-              final extpath = '$selectedPath/bookmark.db';
+                final extpath = '$selectedPath/bookmark.db';
 
-              await dbfile.copy(extpath);
+                await bookmarkDatabaseFile.copy(extpath);
+              }
 
               flutterToast.showToast(
                 child: ToastWrapper(

lib/platform/misc.dart

@@ -16,4 +16,23 @@ class PlatformMiscMethods {
 
     await _methodChannel.invokeMethod('finishMainActivity');
   }
+
+  Future<void> exportFile(
+    String filePath, {
+    required String mimeType,
+    required String fileNameToSaveAs,
+  }) async {
+    if (!Platform.isAndroid) {
+      throw UnsupportedError('Android only');
+    }
+
+    await _methodChannel.invokeMethod<String>(
+      'exportFile',
+      <String, dynamic>{
+        'filePath': filePath,
+        'mimeType': mimeType,
+        'fileNameToSaveAs': fileNameToSaveAs,
+      },
+    );
+  }
 }