Fix secondary display lifecycle cleanup

main.lua

@@ -327,6 +327,7 @@ local function returnToLauncher()
   if love.audio and love.audio.stop then
     pcall(love.audio.stop)
   end
+  pcall(function() require("src.render.SecondScreen").setEnabled(false) end)
 
   local GameVersion = require("src.core.GameVersion")
   local currentVersion = GameVersion.get()

mobile/android/love/src/main/java/org/love2d/android/GameActivity.java

@@ -398,11 +398,15 @@ public class GameActivity extends SDLActivity {
 
     @Override
     protected void onDestroy() {
+        secondaryHostResumed = false;
         if (vibrator != null) {
             Log.d("GameActivity", "Cancelling vibration");
             vibrator.cancel();
         }
         unregisterSecondaryDisplayListener();
+        teardownSecondaryDisplay();
+        secondaryEnabled = false;
+        synchronized (secondaryFrameLock) { secondaryFrame = null; }
         unregisterAudioDeviceCallback();
         abandonAudioFocus();
         onHostDestroy();
@@ -411,6 +415,7 @@ public class GameActivity extends SDLActivity {
 
     @Override
     protected void onPause() {
+        secondaryHostResumed = false;
         if (vibrator != null) {
             Log.d("GameActivity", "Cancelling vibration");
             vibrator.cancel();
@@ -426,6 +431,7 @@ public class GameActivity extends SDLActivity {
     @Override
     public void onResume() {
         super.onResume();
+        secondaryHostResumed = true;
         onHostResume();
         requestGameAudioFocus();
         registerAudioDeviceCallback();
@@ -1933,6 +1939,7 @@ public class GameActivity extends SDLActivity {
     private static volatile int secondaryActivityTarget = Display.INVALID_DISPLAY;
     private static volatile long secondaryRetryAfter;
     private static volatile boolean secondaryEnabled = false;
+    private static volatile boolean secondaryHostResumed = false;
     private static volatile int secondaryTarget = SECONDARY_TARGET_AUTO;
     private static volatile int dualScreenDisplayMode = -1;
     private static volatile byte[] secondaryFrame;
@@ -1963,7 +1970,7 @@ public class GameActivity extends SDLActivity {
         if (self == null) return;
         self.runOnUiThread(new Runnable() {
             @Override public void run() {
-                if (on) {
+                if (on && secondaryHostResumed) {
                     self.refreshDualScreenDisplayMode();
                     self.registerSecondaryDisplayListener();
                     rebindSecondaryDisplay();
@@ -2035,9 +2042,11 @@ public class GameActivity extends SDLActivity {
 
     private static void rebindSecondaryDisplay() {
         GameActivity self = (GameActivity) mSingleton;
-        if (self == null || !secondaryEnabled || secondaryOutputIsPreferred(self)) return;
+        if (self == null || !secondaryHostResumed || !secondaryEnabled
+                || secondaryOutputIsPreferred(self)) return;
         self.runOnUiThread(() -> {
-            if (!secondaryEnabled || secondaryOutputIsPreferred(self)) return;
+            if (!secondaryHostResumed || !secondaryEnabled
+                    || secondaryOutputIsPreferred(self)) return;
             teardownSecondaryDisplay();
             setupSecondaryDisplay();
         });
@@ -2045,7 +2054,8 @@ public class GameActivity extends SDLActivity {
 
     private static void setupSecondaryDisplay() {
         GameActivity self = (GameActivity) mSingleton;
-        if (self == null || !secondaryEnabled || secondaryPresentation != null
+        if (self == null || !secondaryHostResumed || !secondaryEnabled
+                || secondaryPresentation != null
                 || secondaryActivity != null || secondaryActivityPending
                 || android.os.SystemClock.elapsedRealtime() < secondaryRetryAfter) return;
         try {

tests/engine/android_host_extension_test.lua

@@ -58,6 +58,38 @@ check(position("if (secondaryEnabled) registerSecondaryDisplayListener();") <
   "secondary display monitoring starts before initial discovery")
 check(source:find("!monitor.hasDisplay(display.getDisplayId())", 1, true),
   "a disconnected active display is rebound without replacing a live one")
+check(source:find("private static volatile boolean secondaryHostResumed = false;",
+    1, true), "secondary output tracks the primary activity lifecycle")
+check(source:find("if (on && secondaryHostResumed)", 1, true)
+    and source:find("self == null || !secondaryHostResumed || !secondaryEnabled",
+      1, true),
+  "paused hosts cannot reopen secondary output from a late mod frame")
+
+local pause = position("protected void onPause()")
+local paused = assert(source:find("secondaryHostResumed = false;", pause, true))
+local teardown = assert(source:find("teardownSecondaryDisplay();", pause, true))
+local pauseSuper = assert(source:find("super.onPause();", pause, true))
+check(pause < paused and paused < teardown and teardown < pauseSuper,
+  "pause blocks secondary setup before dismissing its output")
+
+local resume = position("public void onResume()")
+local resumeSuper = assert(source:find("super.onResume();", resume, true))
+local resumed = assert(source:find("secondaryHostResumed = true;", resume, true))
+local resumeSetup = assert(source:find("setupSecondaryDisplay();", resume, true))
+check(resume < resumeSuper and resumeSuper < resumed and resumed < resumeSetup,
+  "resume permits secondary setup only after the primary activity resumes")
+
+local destroy = position("protected void onDestroy()")
+local destroyTeardown = assert(source:find("teardownSecondaryDisplay();", destroy, true))
+local destroySuper = assert(source:find("super.onDestroy();", destroy, true))
+check(destroy < destroyTeardown and destroyTeardown < destroySuper,
+  "destroy always dismisses secondary output before SDL destruction")
+
+local mainFile = assert(io.open("main.lua", "rb"))
+local main = mainFile:read("*a")
+mainFile:close()
+check(main:find('require("src.render.SecondScreen").setEnabled(false)', 1, true),
+  "returning from a game disables mod-owned secondary output")
 
 check(not source:lower():find("openxr", 1, true),
   "generic Android activity must not require OpenXR")