Restored the Settings UI. Deferred model loading.

Closes #1031

Signed-off-by: Akos Kitta <a.kitta@arduino.cc>

arduino-ide-extension/src/browser/theia/preferences/preference-tree-generator.ts

@@ -1,16 +1,43 @@
+import {
+  FrontendApplicationState,
+  FrontendApplicationStateService,
+} from '@theia/core/lib/browser/frontend-application-state';
 import { CompositeTreeNode } from '@theia/core/lib/browser/tree/tree';
-import { injectable } from '@theia/core/shared/inversify';
+import { inject, injectable } from '@theia/core/shared/inversify';
 import { PreferenceTreeGenerator as TheiaPreferenceTreeGenerator } from '@theia/preferences/lib/browser/util/preference-tree-generator';
 
 @injectable()
 export class PreferenceTreeGenerator extends TheiaPreferenceTreeGenerator {
+  private shouldHandleChangedSchemaOnReady = false;
+  private state: FrontendApplicationState | undefined;
+
+  @inject(FrontendApplicationStateService)
+  private readonly appStateService: FrontendApplicationStateService;
+
   protected override async init(): Promise<void> {
-    // The IDE2 does not use the default Theia preferences UI.
-    // There is no need to create and keep the the tree model synchronized when there is no UI for it.
+    this.appStateService.onStateChanged((state) => {
+      this.state = state;
+      // manually trigger a model (and UI) refresh if it was requested during the startup phase.
+      if (this.state === 'ready' && this.shouldHandleChangedSchemaOnReady) {
+        this.doHandleChangedSchema();
+      }
+    });
+    return super.init();
+  }
+
+  override doHandleChangedSchema(): void {
+    if (this.state === 'ready') {
+      super.doHandleChangedSchema();
+    }
+    // don't do anything until the app is `ready`, then invoke `doHandleChangedSchema`.
+    this.shouldHandleChangedSchemaOnReady = true;
   }
 
-  // Just returns with the empty root.
   override generateTree(): CompositeTreeNode {
+    if (this.state === 'ready') {
+      return super.generateTree();
+    }
+    // always create an empty root when the app is not ready.
     this._root = this.createRootNode();
     return this._root;
   }