diff --git a/app/src/main/kotlin/info/appdev/chartexample/CubicLineChartActivity.kt b/app/src/main/kotlin/info/appdev/chartexample/CubicLineChartActivity.kt
index 5c14469db..5b0b23680 100644
--- a/app/src/main/kotlin/info/appdev/chartexample/CubicLineChartActivity.kt
+++ b/app/src/main/kotlin/info/appdev/chartexample/CubicLineChartActivity.kt
@@ -147,24 +147,22 @@ class CubicLineChartActivity : DemoBase(), OnSeekBarChangeListener {
             }
 
             R.id.actionToggleValues -> {
-                binding.chart1.data!!.dataSets.forEach {
-                    it?.isDrawValues = !it.isDrawValues
+                binding.chart1.data?.dataSets?.forEach {
+                    it.isDrawValues = !it.isDrawValues
                 }
                 binding.chart1.invalidate()
             }
 
             R.id.actionToggleHighlight -> {
-                if (binding.chart1.data != null) {
-                    binding.chart1.data!!.isHighlightEnabled = !binding.chart1.data!!.isHighlightEnabled
-                    binding.chart1.invalidate()
+                binding.chart1.data?.let {
+                    it.isHighlightEnabled = !it.isHighlightEnabled
                 }
+                binding.chart1.invalidate()
             }
 
             R.id.actionToggleFilled -> {
-                val sets = binding.chart1.data!!.dataSets
-
-                sets.forEach { set ->
-                    set?.let {
+                binding.chart1.data?.dataSets?.forEach { set ->
+                    set.let {
                         if (set.isDrawFilledEnabled)
                             set.setDrawFilled(false)
                         else
@@ -175,20 +173,14 @@ class CubicLineChartActivity : DemoBase(), OnSeekBarChangeListener {
             }
 
             R.id.actionToggleCircles -> {
-                val sets = binding.chart1.data!!.dataSets
-
-                for (iSet in sets) {
-                    val set = iSet as LineDataSet
-                    set.isDrawCirclesEnabled = !iSet.isDrawCirclesEnabled
+                binding.chart1.data?.dataSets?.forEach { set ->
+                    set.isDrawCirclesEnabled = !set.isDrawCirclesEnabled
                 }
                 binding.chart1.invalidate()
             }
 
             R.id.actionToggleCubic -> {
-                val sets = binding.chart1.data!!.dataSets
-
-                for (iSet in sets) {
-                    val set = iSet as LineDataSet
+                binding.chart1.data?.dataSets?.forEach { set ->
                     set.lineMode = if (set.lineMode == LineDataSet.Mode.CUBIC_BEZIER)
                         LineDataSet.Mode.LINEAR
                     else
@@ -198,10 +190,7 @@ class CubicLineChartActivity : DemoBase(), OnSeekBarChangeListener {
             }
 
             R.id.actionToggleStepped -> {
-                val sets = binding.chart1.data!!.dataSets
-
-                for (iSet in sets) {
-                    val set = iSet as LineDataSet
+                binding.chart1.data?.dataSets?.forEach { set ->
                     set.lineMode = if (set.lineMode == LineDataSet.Mode.STEPPED)
                         LineDataSet.Mode.LINEAR
                     else
@@ -211,10 +200,7 @@ class CubicLineChartActivity : DemoBase(), OnSeekBarChangeListener {
             }
 
             R.id.actionToggleHorizontalCubic -> {
-                val sets = binding.chart1.data!!.dataSets
-
-                for (iSet in sets) {
-                    val set = iSet as LineDataSet
+                binding.chart1.data?.dataSets?.forEach { set ->
                     set.lineMode = if (set.lineMode == LineDataSet.Mode.HORIZONTAL_BEZIER)
                         LineDataSet.Mode.LINEAR
                     else