mobile: add android file path helper

android/app/build.gradle

@@ -33,6 +33,7 @@ dependencies {
     implementation fileTree(include: ['*.jar'], dir: 'libs')
     implementation "androidx.appcompat:appcompat:$androidxAppCompatVersion"
     implementation project(':capacitor-android')
+    implementation 'androidx.documentfile:documentfile:1.0.1'
     testImplementation "junit:junit:$junitVersion"
     androidTestImplementation "androidx.test.ext:junit:$androidxJunitVersion"
     androidTestImplementation "androidx.test.espresso:espresso-core:$androidxEspressoCoreVersion"

android/app/src/main/java/com/logseq/app/FileUtil.java

@@ -0,0 +1,138 @@
+package com.logseq.app;
+
+import android.annotation.TargetApi;
+import android.content.ContentUris;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.Build;
+import android.os.Environment;
+import android.provider.DocumentsContract;
+import android.provider.MediaStore;
+// https://stackoverflow.com/questions/29713587/how-to-get-the-real-path-with-action-open-document-tree-intent
+// https://gist.github.com/asifmujteba/d89ba9074bc941de1eaa#file-asfurihelper
+public class FileUtil {
+    @TargetApi(Build.VERSION_CODES.KITKAT)
+    public static String getPath(final Context context, final Uri uri) {
+
+        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
+
+        // DocumentProvider
+        if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
+            // ExternalStorageProvider
+            if (isExternalStorageDocument(uri)) {
+                final String docId = DocumentsContract.getDocumentId(uri);
+                final String[] split = docId.split(":");
+                final String type = split[0];
+
+                if ("primary".equalsIgnoreCase(type)) {
+                    return Environment.getExternalStorageDirectory() + "/" + split[1];
+                }
+
+                // TODO handle non-primary volumes
+            }
+            // DownloadsProvider
+            else if (isDownloadsDocument(uri)) {
+
+                final String id = DocumentsContract.getDocumentId(uri);
+                final Uri contentUri = ContentUris.withAppendedId(
+                        Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
+
+                return getDataColumn(context, contentUri, null, null);
+            }
+            // MediaProvider
+            else if (isMediaDocument(uri)) {
+                final String docId = DocumentsContract.getDocumentId(uri);
+                final String[] split = docId.split(":");
+                final String type = split[0];
+
+                Uri contentUri = null;
+                if ("image".equals(type)) {
+                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
+                } else if ("video".equals(type)) {
+                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
+                } else if ("audio".equals(type)) {
+                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
+                }
+
+                final String selection = "_id=?";
+                final String[] selectionArgs = new String[] {
+                        split[1]
+                };
+
+                return getDataColumn(context, contentUri, selection, selectionArgs);
+            }
+        }
+        // MediaStore (and general)
+        else if ("content".equalsIgnoreCase(uri.getScheme())) {
+
+            // Return the remote address
+            if (isGooglePhotosUri(uri))
+                return uri.getLastPathSegment();
+
+            return getDataColumn(context, uri, null, null);
+        }
+        // File
+        else if ("file".equalsIgnoreCase(uri.getScheme())) {
+            return uri.getPath();
+        }
+
+        return null;
+    }
+
+    public static String getDataColumn(Context context, Uri uri, String selection,
+                                       String[] selectionArgs) {
+
+        Cursor cursor = null;
+        final String column = "_data";
+        final String[] projection = {
+                column
+        };
+
+        try {
+            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
+                    null);
+            if (cursor != null && cursor.moveToFirst()) {
+                final int index = cursor.getColumnIndexOrThrow(column);
+                return cursor.getString(index);
+            }
+        } finally {
+            if (cursor != null)
+                cursor.close();
+        }
+        return null;
+    }
+
+
+    /**
+     * @param uri The Uri to check.
+     * @return Whether the Uri authority is ExternalStorageProvider.
+     */
+    public static boolean isExternalStorageDocument(Uri uri) {
+        return "com.android.externalstorage.documents".equals(uri.getAuthority());
+    }
+
+    /**
+     * @param uri The Uri to check.
+     * @return Whether the Uri authority is DownloadsProvider.
+     */
+    public static boolean isDownloadsDocument(Uri uri) {
+        return "com.android.providers.downloads.documents".equals(uri.getAuthority());
+    }
+
+    /**
+     * @param uri The Uri to check.
+     * @return Whether the Uri authority is MediaProvider.
+     */
+    public static boolean isMediaDocument(Uri uri) {
+        return "com.android.providers.media.documents".equals(uri.getAuthority());
+    }
+
+    /**
+     * @param uri The Uri to check.
+     * @return Whether the Uri authority is Google Photos.
+     */
+    public static boolean isGooglePhotosUri(Uri uri) {
+        return "com.google.android.apps.photos.content".equals(uri.getAuthority());
+    }
+}

android/app/src/main/java/com/logseq/app/FolderPicker.java

@@ -1,8 +1,13 @@
 package com.logseq.app;
 
+import android.content.ContentResolver;
+import android.content.Context;
 import android.content.Intent;
+import android.net.Uri;
+import android.provider.DocumentsContract;
 
 import androidx.activity.result.ActivityResult;
+import androidx.documentfile.provider.DocumentFile;
 
 import com.getcapacitor.JSObject;
 import com.getcapacitor.Plugin;
@@ -27,7 +32,11 @@ public class FolderPicker extends Plugin {
             return;
         }
         JSObject ret = new JSObject();
-        ret.put("result", result.getData().getData());
+        Context context = this.getContext();
+        Uri treeUri = result.getData().getData();
+        Uri docUri = DocumentsContract.buildDocumentUriUsingTree(treeUri,
+                DocumentsContract.getTreeDocumentId(treeUri));
+        ret.put("path", FileUtil.getPath(context, docUri));
         call.resolve(ret);
     }
 }