From a80218d1ed3c73163588ab9c98fee7cb6ab89ea5 Mon Sep 17 00:00:00 2001
From: Erick Zanardo <erickzanardoo@gmail.com>
Date: Fri, 1 Feb 2019 12:53:32 -0200
Subject: [PATCH] Verifying if GestureBinding is ready and if not, throwing a
 meaningful error

---
 doc/input.md  | 3 ++-
 lib/util.dart | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/doc/input.md b/doc/input.md
index 31919554a..48be662d6 100644
--- a/doc/input.md
+++ b/doc/input.md
@@ -34,4 +34,5 @@ Here are some example of more complex Gesture Recognizers:
         return new TapGestureRecognizer()
             ..onTapUp = (TapUpDetails details) => this.handleTap(details.globalPosition);;
     }
-```
\ No newline at end of file
+```
+__ATTENTION:__ `Flame.util.addGestureRecognizer` must be called after the `runApp`, otherwise Flutter's `GestureBinding` will not be initialized yet and exceptions will occur.
diff --git a/lib/util.dart b/lib/util.dart
index 2daab8218..7c85c5da7 100644
--- a/lib/util.dart
+++ b/lib/util.dart
@@ -56,6 +56,10 @@ class Util {
   ///
   /// Use this in order to get it to work in case your app also contains other widgets.
   void addGestureRecognizer(GestureRecognizer recognizer) {
+    if (GestureBinding.instance == null) {
+      throw new Exception("GestureBinding is not initialized yet, this probably happened because addGestureRecognizer was called before the runApp method");
+    }
+
     GestureBinding.instance.pointerRouter.addGlobalRoute((PointerEvent e) {
       if (e is PointerDownEvent) {
         recognizer.addPointer(e);