diff --git a/guide/src/main/java/com/app/hubert/guide/util/ViewUtils.java b/guide/src/main/java/com/app/hubert/guide/util/ViewUtils.java
index c194828..bb0249f 100644
--- a/guide/src/main/java/com/app/hubert/guide/util/ViewUtils.java
+++ b/guide/src/main/java/com/app/hubert/guide/util/ViewUtils.java
@@ -33,6 +33,9 @@ public static Rect getLocationInView(View parent, View child) {
             return result;
         }
         while (tmp != decorView && tmp != parent) {
+            if（tmp == null）{
+                throw new IllegalArgumentException("child can not be null .");
+            }
             tmp.getHitRect(tmpRect);
             if (!tmp.getClass().equals(FRAGMENT_CON)) {
                 result.left += tmpRect.left;