diff --git a/app/src/main/kotlin/info/appdev/chartexample/LineChartDualAxisActivity.kt b/app/src/main/kotlin/info/appdev/chartexample/LineChartDualAxisActivity.kt
index 1ea907a96..cd0c43b64 100644
--- a/app/src/main/kotlin/info/appdev/chartexample/LineChartDualAxisActivity.kt
+++ b/app/src/main/kotlin/info/appdev/chartexample/LineChartDualAxisActivity.kt
@@ -139,7 +139,7 @@ class LineChartDualAxisActivity : DemoBase(), OnSeekBarChangeListener, OnChartVa
         val set3: LineDataSet
 
         if (binding.chart1.data != null &&
-            binding.chart1.data!!.getDataSetCount() > 0
+            binding.chart1.data!!.dataSetCount > 0
         ) {
             set1 = binding.chart1.data!!.getDataSetByIndex(0) as LineDataSet
             set2 = binding.chart1.data!!.getDataSetByIndex(1) as LineDataSet
@@ -217,41 +217,35 @@ class LineChartDualAxisActivity : DemoBase(), OnSeekBarChangeListener, OnChartVa
             }
 
             R.id.actionToggleValues -> {
-                binding.chart1.data!!.dataSets.forEach { set ->
-                    set?.isDrawValues = !set.isDrawValues
+                binding.chart1.data?.dataSets?.forEach { set ->
+                    set.isDrawValues = !set.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 -> {
-                binding.chart1.data!!.dataSets.forEach { set ->
-                    set?.setDrawFilled(!set.isDrawFilledEnabled)
+                binding.chart1.data?.dataSets?.forEach { set ->
+                    set.setDrawFilled(!set.isDrawFilledEnabled)
                 }
                 binding.chart1.invalidate()
             }
 
             R.id.actionToggleCircles -> {
-                val sets = binding.chart1.data!!.dataSets
-
-                for (iSet in sets) {
-                    val set = iSet as LineDataSet
+                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
@@ -261,10 +255,7 @@ class LineChartDualAxisActivity : DemoBase(), OnSeekBarChangeListener, OnChartVa
             }
 
             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
@@ -274,10 +265,7 @@ class LineChartDualAxisActivity : DemoBase(), OnSeekBarChangeListener, OnChartVa
             }
 
             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