feat: add entry in left panel

flutter/lib/desktop/pages/desktop_home_page.dart

@@ -14,6 +14,7 @@ import 'package:flutter_hbb/desktop/pages/desktop_tab_page.dart';
 import 'package:flutter_hbb/desktop/widgets/scroll_wrapper.dart';
 import 'package:flutter_hbb/models/platform_model.dart';
 import 'package:flutter_hbb/models/server_model.dart';
+import 'package:flutter_hbb/plugin/ui_manager.dart';
 import 'package:flutter_hbb/utils/multi_window_manager.dart';
 import 'package:get/get.dart';
 import 'package:provider/provider.dart';
@@ -88,6 +89,7 @@ class _DesktopHomePageState extends State<DesktopHomePage>
                     }
                   },
                 ),
+                buildPluginEntry()
               ],
             ),
           ),
@@ -572,6 +574,22 @@ class _DesktopHomePageState extends State<DesktopHomePage>
     _updateTimer?.cancel();
     super.dispose();
   }
+  
+  Widget buildPluginEntry() {
+    final entries = PluginUiManager.instance.entries.entries;
+    return Offstage(
+      offstage: entries.isEmpty,
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          ...
+          entries.map((entry)  {
+            return entry.value;
+          })
+        ],
+      ),
+    );
+  }
 }
 
 void setPasswordDialog() async {

flutter/lib/plugin/handlers.dart

@@ -2,6 +2,8 @@ import 'dart:convert';
 import 'dart:ffi';
 
 import 'package:ffi/ffi.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_hbb/plugin/ui_manager.dart';
 import 'package:flutter_hbb/plugin/utils/dialogs.dart';
 
 abstract class NativeHandler {
@@ -34,6 +36,15 @@ class NativeUiHandler extends NativeHandler {
         final cbFuncDart = cbFuncNative.asFunction<OnSelectPeersCallbackDart>();
         onSelectPeers(cbFuncDart, userData);
         break;
+      case "register_ui_entry":
+        int cb = evt['on_tap_cb'];
+        int userData = evt['user_data'] ?? 0;
+        String title = evt['title'] ?? "";
+        final cbFuncNative = Pointer.fromAddress(cb)
+            .cast<NativeFunction<OnSelectPeersCallback>>();
+        final cbFuncDart = cbFuncNative.asFunction<OnSelectPeersCallbackDart>();
+        onRegisterUiEntry(title, cbFuncDart, userData);
+        break;
       default:
         return false;
     }
@@ -50,4 +61,19 @@ class NativeUiHandler extends NativeHandler {
       malloc.free(native);
     });
   }
+  
+  void onRegisterUiEntry(String title, OnSelectPeersCallbackDart cbFuncDart, int userData) {
+    Widget widget = InkWell(
+      child: Container(
+        height: 25.0,
+        child: Row(
+          children: [
+            Expanded(child: Text(title)),
+            Icon(Icons.chevron_right_rounded, size: 12.0,)
+          ],
+        ),
+      ),
+    );
+    PluginUiManager.instance.registerEntry(title, widget);
+  }
 }

flutter/lib/plugin/ui_manager.dart

@@ -0,0 +1,17 @@
+import 'package:flutter/material.dart';
+
+class PluginUiManager {
+  PluginUiManager._();
+
+  static PluginUiManager instance = PluginUiManager._();
+
+  Map<String, Widget> entries = <String, Widget>{};
+
+  void registerEntry(String key, Widget widget) {
+    entries[key] = widget;
+  }
+
+  void unregisterEntry(String key) {
+    entries.remove(key);
+  }
+}