diff --git a/app/build.gradle b/app/build.gradle
index 00a9ab4..6faed71 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -27,7 +27,7 @@ android {
             signingConfig signingConfigs.debug
         }
         release {
-            minifyEnabled false
+            minifyEnabled true
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
diff --git a/expandableRecyclerView/src/main/java/pokercc/android/expandablerecyclerview/ExpandableRecyclerView.kt b/expandableRecyclerView/src/main/java/pokercc/android/expandablerecyclerview/ExpandableRecyclerView.kt
index e62d6c2..dc27ce9 100644
--- a/expandableRecyclerView/src/main/java/pokercc/android/expandablerecyclerview/ExpandableRecyclerView.kt
+++ b/expandableRecyclerView/src/main/java/pokercc/android/expandablerecyclerview/ExpandableRecyclerView.kt
@@ -9,6 +9,7 @@ import android.os.Parcelable.ClassLoaderCreator
 import android.util.AttributeSet
 import android.util.Log
 import android.view.View
+import androidx.annotation.Keep
 import androidx.core.view.children
 import androidx.customview.view.AbsSavedState
 import androidx.recyclerview.widget.RecyclerView
@@ -109,6 +110,7 @@ open class ExpandableRecyclerView @JvmOverloads constructor(
      * Hook system method to handle touch event.
      */
     @Suppress("MemberVisibilityCanBePrivate", "unused")
+    @Keep
     protected fun isTransformedTouchPointInView(
         x: Float, y: Float, child: View,
         outLocalPoint: PointF?