From d70bbfed131a0303f8133dd6eefd37f57d0d9169 Mon Sep 17 00:00:00 2001
From: Greg Pomerantz <gmp@wow.st>
Date: Thu, 20 Aug 2026 22:16:23 -0400
Subject: [PATCH] Guard against Gio's null-view detach event (recents-wipe
 SIGABRT)
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Gio's GioView.onDestroyView sends ViewEvent{View: 0} as its detach
signal when the view is destroyed — i.e. the activity going away on a
recents-wipe. An app that forwards the event to Enable() passes a zero
view through to registerFragment, whose GetObjectClass(null) aborts the
process (JNI DETECTED ERROR: java_object == null in call to
GetObjectClass).

Enable() now returns early on a zero view so all callers are covered
even if they forward the event unfiltered, and registerFragment
null-checks as defense in depth. Same fix as pad (fdbffc9); verified
there on a Pixel 9 Pro / Android 17 where the recents swipe used to
crash the app.
---
 ble_android.go | 9 +++++++++
 jni_android.c  | 8 ++++++++
 2 files changed, 17 insertions(+)

diff --git a/ble_android.go b/ble_android.go
index 81f130a..493730b 100644
--- a/ble_android.go
+++ b/ble_android.go
@@ -225,6 +225,15 @@ func NewBLE() *BLE {
 //Enable
 func (b *BLE) Enable(view uintptr) {
 	log.Printf("ble.Enable()")
+	// view == 0 is Gio's detach signal (GioView.onDestroyView sends
+	// ViewEvent{View: 0} when the view is destroyed, e.g. the activity
+	// going away on a recents-wipe). Nothing to register; passing the null
+	// ref on would abort in JNI (GetObjectClass on null). A re-attach
+	// arrives as a fresh event with a live view. Callers that forward the
+	// event unfiltered are protected by this guard.
+	if view == 0 {
+		return
+	}
 	setJVM(app.JavaVM())
 	runInJVM(func(env *JNIEnv) {
 		log.Printf("ble.Enable(): inside runInJVM()")
diff --git a/jni_android.c b/jni_android.c
index 8c3331e..8af028f 100644
--- a/jni_android.c
+++ b/jni_android.c
@@ -5,6 +5,14 @@
 
 void
 registerFragment(JNIEnv *env, jobject view) {
+	if (view == NULL) {
+		// Detach signal (Gio sends ViewEvent{View: 0} when the view is
+		// destroyed, e.g. the activity going away on a recents-wipe).
+		// The Go side already filters these; this guard keeps the JNI
+		// calls safe if one ever slips through (GetObjectClass on null
+		// aborts the process).
+		return;
+	}
 	jclass cls = (*env)->GetObjectClass(env, view);
 	jmethodID mid = (*env)->GetMethodID(env, cls, "getContext", "()Landroid/content/Context;");
 	jobject ctx = (*env)->CallObjectMethod(env, view, mid);