From c84b9283be312c26e3482e0c6cb1bebbb1459b0b Mon Sep 17 00:00:00 2001
From: HenrikJannsen <boilingfrog@gmx.com>
Date: Mon, 18 Mar 2024 11:39:51 +0700
Subject: [PATCH] Ignore calls on onViewDetachedPrivate if view was not
 attached yet. Add check if root scene is not null in case of overlays

---
 .../src/main/java/bisq/desktop/common/view/View.java  | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/apps/desktop/desktop/src/main/java/bisq/desktop/common/view/View.java b/apps/desktop/desktop/src/main/java/bisq/desktop/common/view/View.java
index f9891dcaf4..50976fcc0e 100644
--- a/apps/desktop/desktop/src/main/java/bisq/desktop/common/view/View.java
+++ b/apps/desktop/desktop/src/main/java/bisq/desktop/common/view/View.java
@@ -34,6 +34,7 @@ public abstract class View<R extends Region, M extends Model, C extends Controll
     protected final C controller;
     private final ChangeListener<Scene> sceneChangeListener;
     private ChangeListener<Window> windowChangeListener;
+    private boolean isViewAttached;
 
     public View(R root, M model, C controller) {
         checkNotNull(root, "Root must not be null");
@@ -55,7 +56,8 @@ private void handleSceneChange(Scene oldValue, Scene newScene) {
             } else {
                 // For overlays, we need to wait until window is available
                 windowChangeListener = (observable, oldWindow, newWindow) -> {
-                    if (newWindow != null) {
+                    // As we get called with a delay it might be that the root scene has already changed to null.
+                    if (newWindow != null && root.getScene() != null) {
                         onViewAttachedPrivate();
                     } else {
                         onViewDetachedPrivate();
@@ -82,8 +84,14 @@ public R getRoot() {
     }
 
     private void onViewDetachedPrivate() {
+        // In case we have an overlay we might get called before the onViewAttachedPrivate was called in the windowChangeListener
+        // We avoid that call as it could lead to null pointers in the onViewDetached methods.
+        if (!isViewAttached) {
+            return;
+        }
         controller.onDeactivateInternal();
         onViewDetachedInternal();
+        isViewAttached = false;
     }
 
     private void onViewAttachedPrivate() {
@@ -91,6 +99,7 @@ private void onViewAttachedPrivate() {
         // correct state.
         controller.onActivateInternal();
         onViewAttachedInternal();
+        isViewAttached = true;
     }
 
     // The internal methods should be only used by framework classes (e.g. TabView)