diff --git a/app/src/main/kotlin/info/appdev/chartexample/BubbleChartActivity.kt b/app/src/main/kotlin/info/appdev/chartexample/BubbleChartActivity.kt
index f39148af2..d2119ba18 100644
--- a/app/src/main/kotlin/info/appdev/chartexample/BubbleChartActivity.kt
+++ b/app/src/main/kotlin/info/appdev/chartexample/BubbleChartActivity.kt
@@ -153,23 +153,24 @@ class BubbleChartActivity : DemoBase(), OnSeekBarChangeListener, OnChartValueSel
             }
 
             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.actionToggleIcons -> {
-                for (set in binding.chart1.data!!.dataSets)
-                    set?.isDrawIcons = !set.isDrawIcons
+                binding.chart1.data?.dataSets?.forEach { set ->
+                    set.isDrawIcons = !set.isDrawIcons
+                }
                 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.actionTogglePinch -> {
diff --git a/app/src/main/kotlin/info/appdev/chartexample/ScatterChartActivity.kt b/app/src/main/kotlin/info/appdev/chartexample/ScatterChartActivity.kt
index f6b6cf448..b8c1066d7 100644
--- a/app/src/main/kotlin/info/appdev/chartexample/ScatterChartActivity.kt
+++ b/app/src/main/kotlin/info/appdev/chartexample/ScatterChartActivity.kt
@@ -140,17 +140,17 @@ class ScatterChartActivity : DemoBase(), OnSeekBarChangeListener, OnChartValueSe
             }
 
             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.actionTogglePinch -> {
diff --git a/app/src/main/kotlin/info/appdev/chartexample/SpecificPositionsLineChartActivity.kt b/app/src/main/kotlin/info/appdev/chartexample/SpecificPositionsLineChartActivity.kt
index 0c6b9be0f..441542bd8 100644
--- a/app/src/main/kotlin/info/appdev/chartexample/SpecificPositionsLineChartActivity.kt
+++ b/app/src/main/kotlin/info/appdev/chartexample/SpecificPositionsLineChartActivity.kt
@@ -130,7 +130,7 @@ class SpecificPositionsLineChartActivity : DemoBase(), OnSeekBarChangeListener,
         when (item.itemId) {
             R.id.actionToggleValues -> {
                 binding.chart1.data?.dataSets?.forEach {
-                    it?.isDrawValues = !it.isDrawValues
+                    it.isDrawValues = !it.isDrawValues
                 }
                 binding.chart1.invalidate()
             }
@@ -138,8 +138,8 @@ class SpecificPositionsLineChartActivity : DemoBase(), OnSeekBarChangeListener,
             R.id.actionToggleHighlight -> {
                 binding.chart1.data?.let {
                     it.isHighlightEnabled = !it.isHighlightEnabled
-                    binding.chart1.invalidate()
                 }
+                binding.chart1.invalidate()
             }
 
             R.id.actionToggleFilled -> {
diff --git a/app/src/main/kotlin/info/appdev/chartexample/StackedBarActivity.kt b/app/src/main/kotlin/info/appdev/chartexample/StackedBarActivity.kt
index 4a64fa4b4..08045d77c 100644
--- a/app/src/main/kotlin/info/appdev/chartexample/StackedBarActivity.kt
+++ b/app/src/main/kotlin/info/appdev/chartexample/StackedBarActivity.kt
@@ -110,7 +110,7 @@ class StackedBarActivity : DemoBase(), OnSeekBarChangeListener, OnChartValueSele
         val set1: BarDataSet
 
         if (binding.chart1.data != null &&
-            binding.chart1.data!!.getDataSetCount() > 0
+            binding.chart1.data!!.dataSetCount > 0
         ) {
             set1 = binding.chart1.data!!.getDataSetByIndex(0) as BarDataSet
             set1.entries  = values
@@ -150,24 +150,24 @@ class StackedBarActivity : DemoBase(), OnSeekBarChangeListener, OnChartValueSele
             }
 
             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.actionToggleIcons -> {
-                binding.chart1.data!!.dataSets.forEach { set ->
-                    set?.isDrawIcons = !set.isDrawIcons
+                binding.chart1.data?.dataSets?.forEach { set ->
+                    set.isDrawIcons = !set.isDrawIcons
                 }
                 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.actionTogglePinch -> {
@@ -182,8 +182,9 @@ class StackedBarActivity : DemoBase(), OnSeekBarChangeListener, OnChartValueSele
             }
 
             R.id.actionToggleBarBorders -> {
-                for (set in binding.chart1.data!!.dataSets) (set as BarDataSet).barBorderWidth = if (set.barBorderWidth == 1f) 0f else 1f
-
+                binding.chart1.data?.dataSets?.forEach { set ->
+                    (set as BarDataSet).barBorderWidth = if (set.barBorderWidth == 1f) 0f else 1f
+                }
                 binding.chart1.invalidate()
             }