feature: Keep Awake

There are other React Native modules to use this feature[1], but
unfortunately we get race condition on Android because two pieces of
asynchronous code are manipulating window flags at the same time, and it
might work or not depending on the device you're using.

This fixes the problem by implementing Keep Awake directly in this
module so that we can add some extra glue on Android and make sure
things will work as intended.

* Use the keepAwake prop on UnityView to turn this on and off

1: e.g. @sayem314/react-native-keep-awake

Author: mortend

README.md

@@ -34,7 +34,8 @@ export default function App() {
     <UnityView
       style={{flex: 1, justifyContent: "flex-end"}}
       onMessage={onMessage}
-      onReady={onReady}>
+      onReady={onReady}
+      keepAwake={true}>
       <View
         style={{
           flexDirection: "row",

android/src/main/java/no/fuse/rnunity/RNUnityManager.java

@@ -8,6 +8,7 @@
 import android.view.ViewGroup;
 import android.view.ViewParent;
 import android.view.Window;
+import android.view.WindowManager;
 
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.ReactApplicationContext;
@@ -42,6 +43,8 @@ public String getName() {
     protected UnityPlayer createViewInstance(@Nonnull ThemedReactContext reactContext) {
         Log.d("RNUnityManager", "createViewInstance");
 
+        final RNUnityModule module = RNUnityModule.getInstance();
+
         final Activity activity = reactContext.getCurrentActivity();
         final Handler handler = new Handler(Looper.getMainLooper());
 
@@ -75,8 +78,19 @@ public void run() {
         activity.runOnUiThread(new Runnable() {
             @Override
             public void run() {
-                Log.d("RNUnityManager", "Resetting window flags");
-                window.setFlags(windowFlags, -1);
+                int flags = windowFlags;
+                boolean keepAwake = module.getKeepAwake();
+
+                // Race condition: Keep awake might be enabled or disabled after
+                // the original flags were saved
+                if (keepAwake) {
+                    flags |= WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON;
+                } else {
+                    flags &= ~WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON;
+                }
+
+                Log.d("RNUnityManager", "Resetting window flags; keepAwake=" + keepAwake);
+                window.setFlags(flags, -1);
             }
         });
 
@@ -86,7 +100,7 @@ public void run() {
         player.resume();
 
         // Notify the app that Unity is ready to receive messages
-        RNUnityModule.getInstance().emitEvent("ready", "");
+        module.emitEvent("ready", "");
 
         return player;
     }

android/src/main/java/no/fuse/rnunity/RNUnityModule.java

@@ -1,6 +1,10 @@
 
 package no.fuse.rnunity;
 
+import android.app.Activity;
+import android.util.Log;
+import android.view.WindowManager;
+
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.ReactContextBaseJavaModule;
@@ -17,9 +21,12 @@ public static RNUnityModule getInstance() {
         return instance;
     }
 
+    boolean keepAwake;
+
     public RNUnityModule(ReactApplicationContext reactContext) {
         super(reactContext);
         instance = this;
+        keepAwake = false;
     }
 
     @Override
@@ -47,4 +54,29 @@ public void addListener(String eventName) {
     public void removeListeners(Integer count) {
         // Dummy method
     }
+
+    public boolean getKeepAwake() {
+        return keepAwake;
+    }
+
+    @ReactMethod
+    public void setKeepAwake(boolean enabled) {
+        keepAwake = enabled;
+        final Activity activity = getCurrentActivity();
+
+        if (activity != null) {
+            activity.runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
+                    if (keepAwake) {
+                        Log.d("RNUnityModule", "Turning on keep awake");
+                        activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+                    } else {
+                        Log.d("RNUnityModule", "Turning off keep awake");
+                        activity.getWindow().clearFlags(android.view.WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+                    }
+                }
+            });
+        }
+    }
 }

example/App.tsx

@@ -7,7 +7,8 @@ export default function App() {
     <UnityView
       style={{flex: 1, justifyContent: "flex-end"}}
       onMessage={onMessage}
-      onReady={onReady}>
+      onReady={onReady}
+      keepAwake={true}>
       <View
         style={{
           flexDirection: "row",

ios/RNUnity/RNUnity.m

@@ -167,4 +167,10 @@ - (void)emitEvent:(NSString *)name data:(NSString *)data {
     }
 }
 
+RCT_EXPORT_METHOD(setKeepAwake:(BOOL)keepAwake) {
+    dispatch_async(dispatch_get_main_queue(), ^{
+        [[UIApplication sharedApplication] setIdleTimerDisabled:keepAwake];
+    });
+}
+
 @end

src/UnityModule.ts

@@ -30,6 +30,11 @@ export interface UnityModule {
      * @param message The argument to pass.
      */
     sendMessage(gameObject: string, methodName: string, message: string): void
+
+    /**
+     * Sets whether the screen should stay on.
+     */
+    setKeepAwake(enabled: boolean): void
 }
 
 class UnityModuleImpl implements UnityModule {
@@ -94,6 +99,10 @@ class UnityModuleImpl implements UnityModule {
     sendMessage(gameObject: string, methodName: string, message: string) {
         RNUnity.sendMessage(gameObject, methodName, message)
     }
+
+    setKeepAwake(enabled: boolean) {
+        RNUnity.setKeepAwake(enabled)
+    }
 }
 
 export const UnityModule: UnityModule = new UnityModuleImpl()

src/UnityView.tsx

@@ -11,6 +11,9 @@ export interface UnityViewProps extends ViewProps {
 
     /** Called when Unity is ready to receive messages. */
     onReady?: () => void
+
+    /** Sets whether the screen should stay on. */
+    keepAwake?: boolean
 }
 
 export class UnityView extends React.Component<UnityViewProps> {
@@ -24,9 +27,17 @@ export class UnityView extends React.Component<UnityViewProps> {
         if (this.props.onReady) {
             UnityModule.ensureIsReady(this.props.onReady)
         }
+
+        if (this.props.keepAwake) {
+            UnityModule.setKeepAwake(this.props.keepAwake)
+        }
     }
 
     componentWillUnmount() {
+        if (this.props.keepAwake) {
+            UnityModule.setKeepAwake(false)
+        }
+
         this.listener?.remove()
     }