Makes .monster files open with MonsterCards.

Android/app/src/main/AndroidManifest.xml

@@ -22,32 +22,40 @@
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+
+            <!-- Intent filter for viewing/opening content:// URIs with binary/octet-stream MIME type (.monster) -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <action android:name="android.intent.action.EDIT" />
+
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+
+                <data android:scheme="content" />
+                <data android:mimeType="application/octet-stream" />
+            </intent-filter>
+
+            <!-- Intent filter for file:// URIs ending in .monster or .monster.txt -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <action android:name="android.intent.action.EDIT" />
+
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+
+                <data android:scheme="file" android:host="*" />
+                <data android:pathPattern=".*\\.monster" />
+                <data android:pathPattern=".*\\.monster\\.txt" />
+            </intent-filter>
+
+            <!-- Intent filter for explicitly sharing files/text to Monster Cards -->
             <intent-filter>
                 <action android:name="android.intent.action.SEND" />
 
                 <category android:name="android.intent.category.DEFAULT" />
+
                 <data android:mimeType="text/plain" />
-            </intent-filter>
+                <data android:mimeType="application/octet-stream" />
-            <intent-filter>
-                <action android:name="android.intent.action.VIEW" />
-                <action android:name="android.intent.action.EDIT" />
-                <action android:name="android.intent.action.PICK" />
-                <action android:name="android.intent.action.INSERT" />
-                <action android:name="android.intent.action.INSERT_OR_EDIT" />
-
-                <category android:name="android.intent.category.ALTERNATIVE" />
-                <category android:name="android.intent.category.SELECTED_ALTERNATIVE" />
-                <category android:name="android.intent.category.DEFAULT" />
-
-                <data
-                    android:mimeType="text/plain"
-                    android:scheme="content" />
-                <data
-                    android:mimeType="application/octet-stream"
-                    android:scheme="content" />
-                <data
-                    android:mimeType="text/plain"
-                    android:scheme="file" />
             </intent-filter>
 
             <nav-graph android:value="@navigation/mobile_navigation" />

Android/app/src/main/java/com/majinnaibu/monstercards/MainActivity.java

@@ -1,8 +1,10 @@
 package com.majinnaibu.monstercards;
 
 import android.content.Intent;
+import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
+import android.provider.OpenableColumns;
 import android.view.MenuItem;
 
 import androidx.annotation.NonNull;
@@ -23,6 +25,7 @@ import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.util.Locale;
 import java.util.Objects;
 
 public class MainActivity extends AppCompatActivity {
@@ -76,26 +79,61 @@ public class MainActivity extends AppCompatActivity {
     private String readMonsterJSONFromIntent(@NonNull Intent intent) {
         String action = intent.getAction();
         Bundle extras = intent.getExtras();
-        String type = intent.getType();
-        String json;
         Uri uri = null;
-        if ("android.intent.action.SEND".equals(action) && "text/plain".equals(type)) {
+        if ("android.intent.action.SEND".equals(action)) {
-            uri = extras.getParcelable("android.intent.extra.STREAM");
+            if (extras != null) {
-        } else if ("android.intent.action.VIEW".equals(action) && ("text/plain".equals(type) || "application/octet-stream".equals(type))) {
+                uri = extras.getParcelable(Intent.EXTRA_STREAM);
+            }
+        } else if ("android.intent.action.VIEW".equals(action) || "android.intent.action.EDIT".equals(action)) {
             uri = intent.getData();
         } else {
-            Logger.logError(String.format("unexpected launch configuration action: %s, type: %s", action, type));
+            Logger.logError(String.format("unexpected launch configuration action: %s", action));
+        }
+
+        if (uri == null || !isMonsterFile(uri)) {
+            if (uri != null) {
+                Logger.logError("Ignored file because extension is not .monster or .monster.txt: " + uri);
             }
-        if (uri == null) {
             return null;
         }
-        json = readContentsOfUri(uri);
+
+        String json = readContentsOfUri(uri);
         if (StringHelper.isNullOrEmpty(json)) {
             return null;
         }
         return json;
     }
 
+    private boolean isMonsterFile(@NonNull Uri uri) {
+        String fileName = getFileNameFromUri(uri);
+        if (fileName == null) {
+            return false;
+        }
+        String lowerName = fileName.toLowerCase(Locale.ROOT);
+        return lowerName.endsWith(".monster") || lowerName.endsWith(".monster.txt");
+    }
+
+    @Nullable
+    private String getFileNameFromUri(@NonNull Uri uri) {
+        String displayName = null;
+        if ("content".equals(uri.getScheme())) {
+            try (Cursor cursor = getContentResolver().query(uri, new String[]{OpenableColumns.DISPLAY_NAME}, null, null, null)) {
+                if (cursor != null && cursor.moveToFirst()) {
+                    int nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
+                    if (nameIndex != -1) {
+                        displayName = cursor.getString(nameIndex);
+                    }
+                }
+            } catch (Exception e) {
+                Logger.logError("Error querying display name from content URI", e);
+            }
+        }
+        if (displayName == null) {
+            displayName = uri.getPath();
+        }
+        return displayName;
+    }
+
     @Nullable
     private String readContentsOfUri(Uri uri) {
         StringBuilder builder = new StringBuilder();

docs/Import-Export.md

@@ -162,3 +162,16 @@ Extend the generic sharing feature with specialized, direct sharing channels (to
 - **Sub-Step 7.1 (NFC Sharing)**: Share monster data directly between devices via NFC (NDEF records / Android Beam).
 - **Sub-Step 7.2 (Bluetooth / Wi-Fi Direct)**: Share monster files directly between nearby Android devices via Bluetooth / Wi-Fi.
 - **Sub-Step 7.3 (Web URL with Embedded Payload)**: Generate a shareable Web URL containing compressed/base64-encoded monster JSON data.
+
+---
+
+## 3. Implementation Checklist & Status
+
+- [x] **Step 0**: Restrict app intent filters in `AndroidManifest.xml` (`.monster` & `.monster.txt`) and add runtime filename validation in `MainActivity.java`.
+- [ ] **Step 1**: Refactor import & conversion code into a shared `EntityImporter<T>` interface and `TetraCubeMonsterImporter` class.
+- [ ] **Step 2**: Update Tetra-cube importer class to support the newest Tetra-cube format (`bonusActions`, `mythics`, `blind`, intro descriptions).
+- [ ] **Step 3**: Import from D&D Beyond URL (`https://www.dndbeyond.com/characters/49074997` fetching from character service endpoint `character/v2/character/49074997`).
+- [ ] **Step 4**: Export to internal format described by Open5e document (`Open5eExporter`).
+- [ ] **Step 5**: Import from internal format described by Open5e document (`Open5eImporter`).
+- [ ] **Step 6**: Generic Android Share button feature (`ACTION_SEND`).
+- [ ] **Step 7**: Specific share targets (7.1 NFC, 7.2 Bluetooth, 7.3 Embedded Web URL).