diff --git a/libs/gui/ConsumerBase.cpp b/libs/gui/ConsumerBase.cpp
index f9e292e..abd9921 100644
--- a/libs/gui/ConsumerBase.cpp
+++ b/libs/gui/ConsumerBase.cpp
@@ -96,7 +96,7 @@
 
 void ConsumerBase::freeBufferLocked(int slotIndex) {
     CB_LOGV("freeBufferLocked: slotIndex=%d", slotIndex);
-    mSlots[slotIndex].mGraphicBuffer = 0;
+    mSlots[slotIndex].mGraphicBuffer = nullptr;
     mSlots[slotIndex].mFence = Fence::NO_FENCE;
     mSlots[slotIndex].mFrameNumber = 0;
 }
@@ -110,7 +110,7 @@
         listener = mFrameAvailableListener.promote();
     }
 
-    if (listener != NULL) {
+    if (listener != nullptr) {
         CB_LOGV("actually calling onFrameAvailable");
         listener->onFrameAvailable(item);
     }
@@ -125,7 +125,7 @@
         listener = mFrameAvailableListener.promote();
     }
 
-    if (listener != NULL) {
+    if (listener != nullptr) {
         CB_LOGV("actually calling onFrameReplaced");
         listener->onFrameReplaced(item);
     }
@@ -352,8 +352,8 @@
         return err;
     }
 
-    if (item->mGraphicBuffer != NULL) {
-        if (mSlots[item->mSlot].mGraphicBuffer != NULL) {
+    if (item->mGraphicBuffer != nullptr) {
+        if (mSlots[item->mSlot].mGraphicBuffer != nullptr) {
             freeBufferLocked(item->mSlot);
         }
         mSlots[item->mSlot].mGraphicBuffer = item->mGraphicBuffer;
@@ -468,7 +468,7 @@
     if (slot < 0 || slot >= BufferQueue::NUM_BUFFER_SLOTS) {
         return false;
     }
-    return (mSlots[slot].mGraphicBuffer != NULL &&
+    return (mSlots[slot].mGraphicBuffer != nullptr &&
             mSlots[slot].mGraphicBuffer->handle == graphicBuffer->handle);
 }