diff --git a/app/src/main/kotlin/info/appdev/chartexample/MultiLineChartActivity.kt b/app/src/main/kotlin/info/appdev/chartexample/MultiLineChartActivity.kt
index 978b99595..5dcb532fe 100644
--- a/app/src/main/kotlin/info/appdev/chartexample/MultiLineChartActivity.kt
+++ b/app/src/main/kotlin/info/appdev/chartexample/MultiLineChartActivity.kt
@@ -172,14 +172,13 @@ class MultiLineChartActivity : DemoBase(), OnSeekBarChangeListener, OnChartGestu
             }
 
             R.id.actionToggleCubic -> {
-                val sets = binding.chart1.data!!.dataSets
-
-                for (iSet in sets) {
+                binding.chart1.data?.dataSets?.let { iSet ->
                     val set = iSet as LineDataSet
                     set.lineMode = if (set.lineMode == LineDataSet.Mode.CUBIC_BEZIER)
                         LineDataSet.Mode.LINEAR
                     else
                         LineDataSet.Mode.CUBIC_BEZIER
+                    binding.chart1.invalidate()
                 }
                 binding.chart1.invalidate()
             }