diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemoActivity.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemoActivity.kt
index b12af0e..d512611 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemoActivity.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemoActivity.kt
@@ -26,7 +26,7 @@ import android.widget.ImageView
 
 @RequiresApi(Build.VERSION_CODES.LOLLIPOP) // for View#clipToOutline
 class DemoActivity : AppCompatActivity() {
-    var motionLayout : View? = null
+    private lateinit var motionLayout : MotionLayout
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -40,18 +40,14 @@ class DemoActivity : AppCompatActivity() {
         }
 
         val doShowPaths = intent.getBooleanExtra("showPaths", false)
-        (motionLayout as? MotionLayout)?.setShowPaths(doShowPaths)
+        motionLayout.setShowPaths(doShowPaths)
     }
 
     fun changeState(v: View?) {
-        if (motionLayout == null || motionLayout !is MotionLayout) {
-            return
-        }
-        val ml = motionLayout as? MotionLayout ?: return
-        if (ml.progress > 0.5f) {
-            ml.transitionToStart()
+        if (motionLayout.progress > 0.5f) {
+            motionLayout.transitionToStart()
         } else {
-            ml.transitionToEnd()
+            motionLayout.transitionToEnd()
         }
     }
 }
\ No newline at end of file
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemosAdapter.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemosAdapter.kt
index 774855b..a405182 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemosAdapter.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/DemosAdapter.kt
@@ -22,7 +22,7 @@ import android.view.LayoutInflater
 import android.view.ViewGroup
 import android.widget.TextView
 
-class DemosAdapter(private val myDataset: Array<DemosAdapter.Demo>) :
+class DemosAdapter(private val dataset: Array<DemosAdapter.Demo>) :
         RecyclerView.Adapter<DemosAdapter.ViewHolder>() {
 
     data class Demo(val title: String, val description : String, val layout : Int = 0, val activity : Class<*> = DemoActivity::class.java) {
@@ -54,11 +54,11 @@ class DemosAdapter(private val myDataset: Array<DemosAdapter.Demo>) :
     }
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
-        holder.title.text = myDataset[position].title
-        holder.description.text = myDataset[position].description
-        holder.layoutFileId = myDataset[position].layout
-        holder.activity = myDataset[position].activity
+        holder.title.text = dataset[position].title
+        holder.description.text = dataset[position].description
+        holder.layoutFileId = dataset[position].layout
+        holder.activity = dataset[position].activity
     }
 
-    override fun getItemCount() = myDataset.size
+    override fun getItemCount() = dataset.size
 }
\ No newline at end of file
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/MainActivity.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/MainActivity.kt
index 914a219..7ad2da0 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/MainActivity.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/MainActivity.kt
@@ -18,7 +18,7 @@ class MainActivity : AppCompatActivity(), CompoundButton.OnCheckedChangeListener
     private lateinit var viewManager: RecyclerView.LayoutManager
     private var doShowPaths = false
 
-    private val myDataset: Array<DemosAdapter.Demo> = arrayOf(
+    private val dataset: Array<DemosAdapter.Demo> = arrayOf(
             DemosAdapter.Demo("Basic Example (1/2)", "Basic motion example using referenced ConstraintLayout files", R.layout.motion_01_basic),
             DemosAdapter.Demo("Basic Example (2/2)", "Basic motion example using ConstraintSets defined in the MotionScene file", R.layout.motion_02_basic),
             DemosAdapter.Demo("Custom Attribute", "Show color interpolation (custom attribute)", R.layout.motion_03_custom_attribute),
@@ -48,7 +48,7 @@ class MainActivity : AppCompatActivity(), CompoundButton.OnCheckedChangeListener
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
         viewManager = LinearLayoutManager(this)
-        viewAdapter = DemosAdapter(myDataset)
+        viewAdapter = DemosAdapter(dataset)
 
         recyclerView = findViewById<RecyclerView>(R.id.recyclerview).apply {
             setHasFixedSize(true)
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/CustomAdapter.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/CustomAdapter.kt
index 5da7670..5d87ce0 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/CustomAdapter.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/CustomAdapter.kt
@@ -49,7 +49,7 @@ class CustomAdapter(private val userList: ArrayList<User>): RecyclerView.Adapter
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
         val v = LayoutInflater.from(parent.context).inflate(R.layout.item_layout, parent, false)
-        return ViewHolder(v);
+        return ViewHolder(v)
     }
 
     override fun getItemCount(): Int {
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExample2Activity.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExample2Activity.kt
index 1b4c543..9038294 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExample2Activity.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExample2Activity.kt
@@ -57,10 +57,10 @@ class FragmentExample2Activity : AppCompatActivity(), View.OnClickListener, Moti
     override fun onTransitionCompleted(p0: MotionLayout?, p1: Int) {
     }
 
-    var lastProgress = 0f
+    private var lastProgress = 0f
 
-    var fragment : Fragment? = null
-    var last : Float = 0f
+    private var fragment : Fragment? = null
+    private var last : Float = 0f
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExampleActivity.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExampleActivity.kt
index 142aa67..0c59bb8 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExampleActivity.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/fragmentsdemo/FragmentExampleActivity.kt
@@ -58,10 +58,10 @@ class FragmentExampleActivity : AppCompatActivity(), View.OnClickListener, Motio
     override fun onTransitionCompleted(p0: MotionLayout?, p1: Int) {
     }
 
-    var lastProgress = 0f
+    private var lastProgress = 0f
 
-    var fragment : Fragment? = null
-    var last : Float = 0f
+    private var fragment : Fragment? = null
+    private var last : Float = 0f
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/BoundsImageView.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/BoundsImageView.kt
index 0394cd9..700fc77 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/BoundsImageView.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/BoundsImageView.kt
@@ -26,17 +26,17 @@ class BoundsImageView @JvmOverloads constructor(
         context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
 ) : ImageView(context, attrs, defStyleAttr) {
 
-    private var mPaint = Paint()
+    private var paint = Paint()
 
     init {
-        mPaint.setARGB(255, 200, 0, 0)
-        mPaint.strokeWidth = 4f
+        paint.setARGB(255, 200, 0, 0)
+        paint.strokeWidth = 4f
     }
 
 
     override fun onDraw(canvas: Canvas?) {
         super.onDraw(canvas)
-        canvas?.drawLine(0f, 0f, width.toFloat(), height.toFloat(), mPaint)
-        canvas?.drawLine(0f, height.toFloat(), width.toFloat(), 0f, mPaint)
+        canvas?.drawLine(0f, 0f, width.toFloat(), height.toFloat(), paint)
+        canvas?.drawLine(0f, height.toFloat(), width.toFloat(), 0f, paint)
     }
 }
\ No newline at end of file
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/TouchFrameLayout.java b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/TouchFrameLayout.java
index 3dd49ac..81853ab 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/TouchFrameLayout.java
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/utils/TouchFrameLayout.java
@@ -19,10 +19,8 @@
 import android.content.Context;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
-import android.support.constraint.motion.MotionLayout;
 import android.support.v4.view.NestedScrollingParent2;
 import android.util.AttributeSet;
-import android.view.MotionEvent;
 import android.view.View;
 import android.widget.FrameLayout;
 
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/Page.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/Page.kt
index 8d35f3f..3aaeb7d 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/Page.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/Page.kt
@@ -24,7 +24,7 @@ import android.view.View
 
 class Page  : Fragment() {
 
-    var layoutId = 0
+    private var layoutId = 0
 
     override fun setArguments(args: Bundle?) {
         super.setArguments(args)
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity.kt
index a98d0ff..34269bf 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity.kt
@@ -20,18 +20,16 @@ import android.os.Bundle
 import android.support.constraint.motion.MotionLayout
 import android.support.v4.view.ViewPager
 import android.support.v7.app.AppCompatActivity
-import android.view.View
 import com.google.androidstudio.motionlayoutexample.R
 import kotlinx.android.synthetic.main.motion_16_viewpager.*
 
 class ViewPagerActivity : AppCompatActivity() {
-    var motionLayout: View? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         val layout = R.layout.motion_16_viewpager
         setContentView(layout)
-        motionLayout = findViewById(R.id.motionLayout)
+        val motionLayout = findViewById<MotionLayout>(R.id.motionLayout)
 
         val adapter = ViewPagerAdapter(supportFragmentManager)
         adapter.addPage("Page 1", R.layout.motion_16_viewpager_page1)
@@ -44,6 +42,6 @@ class ViewPagerActivity : AppCompatActivity() {
         }
 
         val doShowPaths = intent.getBooleanExtra("showPaths", false)
-        (motionLayout as? MotionLayout)?.setShowPaths(doShowPaths)
+        motionLayout.setShowPaths(doShowPaths)
     }
 }
\ No newline at end of file
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity2.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity2.kt
index 685422e..b881b1b 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity2.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerActivity2.kt
@@ -25,13 +25,12 @@ import com.google.androidstudio.motionlayoutexample.R
 import kotlinx.android.synthetic.main.motion_16_viewpager.*
 
 class ViewPagerActivity2 : AppCompatActivity() {
-    var motionLayout: View? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         val layout = R.layout.motion_23_viewpager
         setContentView(layout)
-        motionLayout = findViewById(R.id.motionLayout)
+        val motionLayout = findViewById<MotionLayout>(R.id.motionLayout)
 
         val adapter = ViewPagerAdapter(supportFragmentManager)
         adapter.addPage("Page 1", R.layout.motion_16_viewpager_page1)
@@ -44,6 +43,6 @@ class ViewPagerActivity2 : AppCompatActivity() {
         }
 
         val doShowPaths = intent.getBooleanExtra("showPaths", false)
-        (motionLayout as? MotionLayout)?.setShowPaths(doShowPaths)
+        motionLayout.setShowPaths(doShowPaths)
     }
 }
\ No newline at end of file
diff --git a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerAdapter.kt b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerAdapter.kt
index bd02bd5..db60031 100644
--- a/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerAdapter.kt
+++ b/motionlayout/src/main/java/com/google/androidstudio/motionlayoutexample/viewpagerdemo/ViewPagerAdapter.kt
@@ -23,24 +23,24 @@ import android.support.v4.app.FragmentPagerAdapter
 
 class ViewPagerAdapter(fm: FragmentManager?) : FragmentPagerAdapter(fm) {
 
-    private val mFragmentList = ArrayList<Fragment>()
-    private val mFragmentTitleList = ArrayList<String>()
+    private val fragmentList = ArrayList<Fragment>()
+    private val fragmentTitleList = ArrayList<String>()
 
     override fun getItem(position: Int): Fragment {
-        return mFragmentList[position]
+        return fragmentList[position]
     }
 
     override fun getCount(): Int {
-        return mFragmentList.size
+        return fragmentList.size
     }
 
     private fun addFragment(fragment: Fragment, title: String) {
-        mFragmentList.add(fragment)
-        mFragmentTitleList.add(title)
+        fragmentList.add(fragment)
+        fragmentTitleList.add(title)
     }
 
     override fun getPageTitle(position: Int): CharSequence? {
-        return mFragmentTitleList[position]
+        return fragmentTitleList[position]
     }
 
     fun addPage(s: String, layout: Int) {