diff --git a/twidere.component.nyan/src/main/java/org/mariotaku/twidere/nyan/NyanWallpaperService.java b/twidere.component.nyan/src/main/java/org/mariotaku/twidere/nyan/NyanWallpaperService.java
index 52ef99158..003412420 100644
--- a/twidere.component.nyan/src/main/java/org/mariotaku/twidere/nyan/NyanWallpaperService.java
+++ b/twidere.component.nyan/src/main/java/org/mariotaku/twidere/nyan/NyanWallpaperService.java
@@ -115,10 +115,12 @@ public class NyanWallpaperService extends WallpaperService implements NyanConsta
 
         private void updateHelperState() {
             final PowerManager pm = (PowerManager) getSystemService(POWER_SERVICE);
-            if (pm.isScreenOn()) {
-                mHelper.start();
-            } else {
-                mHelper.stop();
+            if (pm != null) {
+                if (pm.isScreenOn()) {
+                    mHelper.start();
+                } else {
+                    mHelper.stop();
+                }
             }
         }