diff --git a/libs/hwui/Animator.h b/libs/hwui/Animator.h
index fdae0f32d4e64..1954b88107a36 100644
--- a/libs/hwui/Animator.h
+++ b/libs/hwui/Animator.h
@@ -114,7 +114,7 @@ protected:
         Finished,
     };
 
-    BaseRenderNodeAnimator(float finalValue);
+    explicit BaseRenderNodeAnimator(float finalValue);
     virtual ~BaseRenderNodeAnimator();
 
     virtual float getValue(RenderNode* target) const = 0;
diff --git a/libs/hwui/AssetAtlas.cpp b/libs/hwui/AssetAtlas.cpp
index 6afff1b7158ee..e2e7037202b86 100644
--- a/libs/hwui/AssetAtlas.cpp
+++ b/libs/hwui/AssetAtlas.cpp
@@ -27,7 +27,7 @@ namespace uirenderer {
 // Lifecycle
 ///////////////////////////////////////////////////////////////////////////////
 
-void AssetAtlas::init(sp<GraphicBuffer> buffer, int64_t* map, int count) {
+void AssetAtlas::init(const sp<GraphicBuffer>& buffer, int64_t* map, int count) {
     if (mImage) {
         return;
     }
diff --git a/libs/hwui/AssetAtlas.h b/libs/hwui/AssetAtlas.h
index 75400ff494c38..b32e51851b942 100644
--- a/libs/hwui/AssetAtlas.h
+++ b/libs/hwui/AssetAtlas.h
@@ -109,7 +109,7 @@ public:
      * initialized. To re-initialize the atlas, you must
      * first call terminate().
      */
-    ANDROID_API void init(sp<GraphicBuffer> buffer, int64_t* map, int count);
+    ANDROID_API void init(const sp<GraphicBuffer>& buffer, int64_t* map, int count);
 
     /**
      * Destroys the atlas texture. This object can be
diff --git a/libs/hwui/DisplayListOp.h b/libs/hwui/DisplayListOp.h
index 2a859132e7832..51b987c7ed85b 100644
--- a/libs/hwui/DisplayListOp.h
+++ b/libs/hwui/DisplayListOp.h
@@ -111,7 +111,7 @@ public:
 class DrawOp : public DisplayListOp {
 friend class MergingDrawBatch;
 public:
-    DrawOp(const SkPaint* paint)
+    explicit DrawOp(const SkPaint* paint)
             : mPaint(paint), mQuickRejected(false) {}
 
     virtual void defer(DeferStateStruct& deferStruct, int saveCount, int level,
@@ -244,7 +244,7 @@ public:
     }
 
     // default empty constructor for bounds, to be overridden in child constructor body
-    DrawBoundedOp(const SkPaint* paint): DrawOp(paint) { }
+    explicit DrawBoundedOp(const SkPaint* paint): DrawOp(paint) { }
 
     virtual bool getLocalBounds(Rect& localBounds) override {
         localBounds.set(mLocalBounds);
@@ -269,7 +269,7 @@ protected:
 
 class SaveOp : public StateOp {
 public:
-    SaveOp(int flags)
+    explicit SaveOp(int flags)
             : mFlags(flags) {}
 
     virtual void defer(DeferStateStruct& deferStruct, int saveCount, int level,
@@ -295,7 +295,7 @@ private:
 
 class RestoreToCountOp : public StateOp {
 public:
-    RestoreToCountOp(int count)
+    explicit RestoreToCountOp(int count)
             : mCount(count) {}
 
     virtual void defer(DeferStateStruct& deferStruct, int saveCount, int level,
@@ -408,7 +408,7 @@ private:
 
 class RotateOp : public StateOp {
 public:
-    RotateOp(float degrees)
+    explicit RotateOp(float degrees)
             : mDegrees(degrees) {}
 
     virtual void applyState(OpenGLRenderer& renderer, int saveCount) const override {
@@ -467,7 +467,7 @@ private:
 
 class SetMatrixOp : public StateOp {
 public:
-    SetMatrixOp(const SkMatrix& matrix)
+    explicit SetMatrixOp(const SkMatrix& matrix)
             : mMatrix(matrix) {}
 
     virtual void applyState(OpenGLRenderer& renderer, int saveCount) const override {
@@ -492,7 +492,7 @@ private:
 
 class ConcatMatrixOp : public StateOp {
 public:
-    ConcatMatrixOp(const SkMatrix& matrix)
+    explicit ConcatMatrixOp(const SkMatrix& matrix)
             : mMatrix(matrix) {}
 
     virtual void applyState(OpenGLRenderer& renderer, int saveCount) const override {
@@ -511,7 +511,7 @@ private:
 
 class ClipOp : public StateOp {
 public:
-    ClipOp(SkRegion::Op op) : mOp(op) {}
+    explicit ClipOp(SkRegion::Op op) : mOp(op) {}
 
     virtual void defer(DeferStateStruct& deferStruct, int saveCount, int level,
             bool useQuickReject) override {
@@ -1384,7 +1384,7 @@ private:
 
 class DrawFunctorOp : public DrawOp {
 public:
-    DrawFunctorOp(Functor* functor)
+    explicit DrawFunctorOp(Functor* functor)
             : DrawOp(nullptr), mFunctor(functor) {}
 
     virtual void applyDraw(OpenGLRenderer& renderer, Rect& dirty) override {
diff --git a/libs/hwui/Image.h b/libs/hwui/Image.h
index 25145354a4f0d..b8f5a5bec087a 100644
--- a/libs/hwui/Image.h
+++ b/libs/hwui/Image.h
@@ -38,7 +38,7 @@ public:
      * cannot be created, getTexture() will return 0 and getImage() will
      * return EGL_NO_IMAGE_KHR.
      */
-    Image(sp<GraphicBuffer> buffer);
+    explicit Image(sp<GraphicBuffer> buffer);
     ~Image();
 
     /**
diff --git a/libs/hwui/Interpolator.h b/libs/hwui/Interpolator.h
index 66ce1197f0603..65120087ff60c 100644
--- a/libs/hwui/Interpolator.h
+++ b/libs/hwui/Interpolator.h
@@ -43,7 +43,7 @@ public:
 
 class ANDROID_API AccelerateInterpolator : public Interpolator {
 public:
-    AccelerateInterpolator(float factor) : mFactor(factor), mDoubleFactor(factor*2) {}
+    explicit AccelerateInterpolator(float factor) : mFactor(factor), mDoubleFactor(factor*2) {}
     virtual float interpolate(float input) override;
 private:
     const float mFactor;
@@ -52,7 +52,7 @@ private:
 
 class ANDROID_API AnticipateInterpolator : public Interpolator {
 public:
-    AnticipateInterpolator(float tension) : mTension(tension) {}
+    explicit AnticipateInterpolator(float tension) : mTension(tension) {}
     virtual float interpolate(float input) override;
 private:
     const float mTension;
@@ -60,7 +60,7 @@ private:
 
 class ANDROID_API AnticipateOvershootInterpolator : public Interpolator {
 public:
-    AnticipateOvershootInterpolator(float tension) : mTension(tension) {}
+    explicit AnticipateOvershootInterpolator(float tension) : mTension(tension) {}
     virtual float interpolate(float input) override;
 private:
     const float mTension;
@@ -73,7 +73,7 @@ public:
 
 class ANDROID_API CycleInterpolator : public Interpolator {
 public:
-    CycleInterpolator(float cycles) : mCycles(cycles) {}
+    explicit CycleInterpolator(float cycles) : mCycles(cycles) {}
     virtual float interpolate(float input) override;
 private:
     const float mCycles;
@@ -81,7 +81,7 @@ private:
 
 class ANDROID_API DecelerateInterpolator : public Interpolator {
 public:
-    DecelerateInterpolator(float factor) : mFactor(factor) {}
+    explicit DecelerateInterpolator(float factor) : mFactor(factor) {}
     virtual float interpolate(float input) override;
 private:
     const float mFactor;
@@ -94,7 +94,7 @@ public:
 
 class ANDROID_API OvershootInterpolator : public Interpolator {
 public:
-    OvershootInterpolator(float tension) : mTension(tension) {}
+    explicit OvershootInterpolator(float tension) : mTension(tension) {}
     virtual float interpolate(float input) override;
 private:
     const float mTension;
diff --git a/libs/hwui/renderstate/RenderState.h b/libs/hwui/renderstate/RenderState.h
index 731d9bbb33554..9e0fb121be652 100644
--- a/libs/hwui/renderstate/RenderState.h
+++ b/libs/hwui/renderstate/RenderState.h
@@ -106,7 +106,7 @@ private:
     void interruptForFunctorInvoke();
     void resumeFromFunctorInvoke();
 
-    RenderState(renderthread::RenderThread& thread);
+    explicit RenderState(renderthread::RenderThread& thread);
     ~RenderState();
 
 
diff --git a/libs/hwui/renderthread/EglManager.h b/libs/hwui/renderthread/EglManager.h
index 459baed70e40a..41047fecf960f 100644
--- a/libs/hwui/renderthread/EglManager.h
+++ b/libs/hwui/renderthread/EglManager.h
@@ -86,7 +86,7 @@ public:
 private:
     friend class RenderThread;
 
-    EglManager(RenderThread& thread);
+    explicit EglManager(RenderThread& thread);
     // EglContext is never destroyed, method is purposely not implemented
     ~EglManager();
 
diff --git a/libs/hwui/thread/TaskManager.h b/libs/hwui/thread/TaskManager.h
index 0e4ffdca496df..c9d12bc6044b1 100644
--- a/libs/hwui/thread/TaskManager.h
+++ b/libs/hwui/thread/TaskManager.h
@@ -78,7 +78,7 @@ private:
 
     class WorkerThread: public Thread {
     public:
-        explicit WorkerThread(const String8 name): mSignal(Condition::WAKE_UP_ONE), mName(name) { }
+        explicit WorkerThread(const String8& name): mSignal(Condition::WAKE_UP_ONE), mName(name) { }
 
         bool addTask(const TaskWrapper& task);
         size_t getTaskCount() const;
diff --git a/libs/hwui/utils/Timing.h b/libs/hwui/utils/Timing.h
index dd8847add2e88..4b1fabe42c359 100644
--- a/libs/hwui/utils/Timing.h
+++ b/libs/hwui/utils/Timing.h
@@ -22,7 +22,7 @@
 #define TIME_METHOD() MethodTimer __method_timer(__func__)
 class MethodTimer {
 public:
-    MethodTimer(const char* name)
+    explicit MethodTimer(const char* name)
             : mMethodName(name) {
         gettimeofday(&mStart, nullptr);
     }
diff --git a/tools/aapt/AaptAssets.h b/tools/aapt/AaptAssets.h
index 4fdc9640e8e55..eadd48a6c2619 100644
--- a/tools/aapt/AaptAssets.h
+++ b/tools/aapt/AaptAssets.h
@@ -103,7 +103,7 @@ struct AaptGroupEntry
 {
 public:
     AaptGroupEntry() {}
-    AaptGroupEntry(const ConfigDescription& config) : mParams(config) {}
+    explicit AaptGroupEntry(const ConfigDescription& config) : mParams(config) {}
 
     bool initFromDirName(const char* dir, String8* resType);
 
@@ -312,7 +312,7 @@ public:
         : isPublic(false), isJavaSymbol(false), typeCode(TYPE_UNKNOWN)
     {
     }
-    AaptSymbolEntry(const String8& _name)
+    explicit AaptSymbolEntry(const String8& _name)
         : name(_name), isPublic(false), isJavaSymbol(false), typeCode(TYPE_UNKNOWN)
     {
     }