Fix preview floating panel compatibility with both 2020.3 and 2021.1 (#973)

idea-plugin/gradle.properties

@@ -11,5 +11,5 @@ plugin.until.build=212.*
 plugin.verifier.ide.versions=2020.3.2, 2021.1
 
 platform.type=IC
-platform.version=2020.3.2
+platform.version=2021.1
 platform.download.sources=true

idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/ide/preview/PreviewFloatingToolbarProvider.kt

@@ -26,14 +26,20 @@ class PreviewFloatingToolbarProvider : AbstractFloatingToolbarProvider(PREVIEW_E
     override fun register(toolbar: FloatingToolbarComponent, parentDisposable: Disposable) {
         try {
             // todo: use provided data context once 2020.3 is no longer supported
-            val toolbarImpl = toolbar as? FloatingToolbarComponentImpl ?: return
-            val editor = toolbarImpl.getData(CommonDataKeys.EDITOR.name) as? Editor ?: return
+            val toolbarClass = FloatingToolbarComponentImpl::class.java
+            val getDataMethod = toolbarClass.getMethod("getData", String::class.java)
+            val editor = getDataMethod.invoke(toolbar, CommonDataKeys.EDITOR.name) as? Editor ?: return
             registerComponent(toolbar, editor, parentDisposable)
         } catch (e: Exception) {
             LOG.error(e)
         }
     }
 
+    override fun register(dataContext: DataContext, component: FloatingToolbarComponent, parentDisposable: Disposable) {
+        val editor = dataContext.getData(CommonDataKeys.EDITOR) ?: return
+        registerComponent(component, editor, parentDisposable)
+    }
+
     private fun registerComponent(
         component: FloatingToolbarComponent,
         editor: Editor,