diff --git a/app/src/main/java/info/appdev/chartexample/custom/MyMarkerView.java b/app/src/main/java/info/appdev/chartexample/custom/MyMarkerView.java
deleted file mode 100644
index 5161c53793..0000000000
--- a/app/src/main/java/info/appdev/chartexample/custom/MyMarkerView.java
+++ /dev/null
@@ -1,52 +0,0 @@
-
-package info.appdev.chartexample.custom;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.widget.TextView;
-
-import com.github.mikephil.charting.components.MarkerView;
-import com.github.mikephil.charting.data.CandleEntry;
-import com.github.mikephil.charting.data.Entry;
-import com.github.mikephil.charting.highlight.Highlight;
-import com.github.mikephil.charting.utils.MPPointF;
-import com.github.mikephil.charting.utils.Utils;
-
-import info.appdev.chartexample.R;
-
-/**
- * Custom implementation of the MarkerView.
- *
- * @author Philipp Jahoda
- */
-@SuppressLint("ViewConstructor")
-public class MyMarkerView extends MarkerView {
-
-    private final TextView tvContent;
-
-    public MyMarkerView(Context context, int layoutResource) {
-        super(context, layoutResource);
-
-        tvContent = findViewById(R.id.tvContent);
-    }
-
-    // runs every time the MarkerView is redrawn, can be used to update the
-    // content (user-interface)
-    @Override
-    public void refreshContent(Entry e, Highlight highlight) {
-
-        if (e instanceof CandleEntry ce) {
-			tvContent.setText(Utils.formatNumber(ce.getHigh(), 0, true));
-        } else {
-
-            tvContent.setText(Utils.formatNumber(e.getY(), 0, true));
-        }
-
-        super.refreshContent(e, highlight);
-    }
-
-    @Override
-    public MPPointF getOffset() {
-        return new MPPointF(-(getWidth() / 2), -getHeight());
-    }
-}
diff --git a/app/src/main/java/info/appdev/chartexample/custom/MyMarkerView.kt b/app/src/main/java/info/appdev/chartexample/custom/MyMarkerView.kt
new file mode 100644
index 0000000000..ffae0e0c7d
--- /dev/null
+++ b/app/src/main/java/info/appdev/chartexample/custom/MyMarkerView.kt
@@ -0,0 +1,36 @@
+package info.appdev.chartexample.custom
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.widget.TextView
+import com.github.mikephil.charting.components.MarkerView
+import com.github.mikephil.charting.data.CandleEntry
+import com.github.mikephil.charting.data.Entry
+import com.github.mikephil.charting.highlight.Highlight
+import com.github.mikephil.charting.utils.MPPointF
+import com.github.mikephil.charting.utils.Utils
+import info.appdev.chartexample.R
+
+/**
+ * Custom implementation of the MarkerView.
+ */
+@SuppressLint("ViewConstructor")
+class MyMarkerView(context: Context?, layoutResource: Int) : MarkerView(context, layoutResource) {
+    private val tvContent: TextView = findViewById(R.id.tvContent)
+
+    // runs every time the MarkerView is redrawn, can be used to update the
+    // content (user-interface)
+    override fun refreshContent(e: Entry, highlight: Highlight?) {
+        if (e is CandleEntry) {
+            tvContent.text = Utils.formatNumber(e.high, 0, true)
+        } else {
+            tvContent.text = Utils.formatNumber(e.y, 0, true)
+        }
+
+        super.refreshContent(e, highlight)
+    }
+
+    override fun getOffset(): MPPointF {
+        return MPPointF(-(width / 2).toFloat(), -height.toFloat())
+    }
+}
diff --git a/app/src/main/java/info/appdev/chartexample/custom/RadarMarkerView.java b/app/src/main/java/info/appdev/chartexample/custom/RadarMarkerView.java
deleted file mode 100644
index 686634dad5..0000000000
--- a/app/src/main/java/info/appdev/chartexample/custom/RadarMarkerView.java
+++ /dev/null
@@ -1,49 +0,0 @@
-
-package info.appdev.chartexample.custom;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.graphics.Typeface;
-import android.widget.TextView;
-
-import com.github.mikephil.charting.components.MarkerView;
-import com.github.mikephil.charting.data.Entry;
-import com.github.mikephil.charting.highlight.Highlight;
-import com.github.mikephil.charting.utils.MPPointF;
-
-import java.text.DecimalFormat;
-
-import info.appdev.chartexample.R;
-
-/**
- * Custom implementation of the MarkerView.
- *
- * @author Philipp Jahoda
- */
-@SuppressLint("ViewConstructor")
-public class RadarMarkerView extends MarkerView {
-
-    private final TextView tvContent;
-    private final DecimalFormat format = new DecimalFormat("##0");
-
-    public RadarMarkerView(Context context, int layoutResource) {
-        super(context, layoutResource);
-
-        tvContent = findViewById(R.id.tvContent);
-        tvContent.setTypeface(Typeface.createFromAsset(context.getAssets(), "OpenSans-Light.ttf"));
-    }
-
-    // runs every time the MarkerView is redrawn, can be used to update the
-    // content (user-interface)
-    @Override
-    public void refreshContent(Entry e, Highlight highlight) {
-        tvContent.setText(String.format("%s %%", format.format(e.getY())));
-
-        super.refreshContent(e, highlight);
-    }
-
-    @Override
-    public MPPointF getOffset() {
-        return new MPPointF(-(getWidth() / 2), -getHeight() - 10);
-    }
-}
diff --git a/app/src/main/java/info/appdev/chartexample/custom/RadarMarkerView.kt b/app/src/main/java/info/appdev/chartexample/custom/RadarMarkerView.kt
new file mode 100644
index 0000000000..b45c472657
--- /dev/null
+++ b/app/src/main/java/info/appdev/chartexample/custom/RadarMarkerView.kt
@@ -0,0 +1,37 @@
+package info.appdev.chartexample.custom
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.graphics.Typeface
+import android.widget.TextView
+import com.github.mikephil.charting.components.MarkerView
+import com.github.mikephil.charting.data.Entry
+import com.github.mikephil.charting.highlight.Highlight
+import com.github.mikephil.charting.utils.MPPointF
+import info.appdev.chartexample.R
+import java.text.DecimalFormat
+
+/**
+ * Custom implementation of the MarkerView.
+ */
+@SuppressLint("ViewConstructor")
+class RadarMarkerView(context: Context, layoutResource: Int) : MarkerView(context, layoutResource) {
+    private val tvContent: TextView = findViewById(R.id.tvContent)
+    private val format = DecimalFormat("##0")
+
+    init {
+        tvContent.setTypeface(Typeface.createFromAsset(context.assets, "OpenSans-Light.ttf"))
+    }
+
+    // runs every time the MarkerView is redrawn, can be used to update the
+    // content (user-interface)
+    override fun refreshContent(e: Entry, highlight: Highlight?) {
+        tvContent.text = String.format("%s %%", format.format(e.y.toDouble()))
+
+        super.refreshContent(e, highlight)
+    }
+
+    override fun getOffset(): MPPointF {
+        return MPPointF(-(width / 2).toFloat(), (-height - 10).toFloat())
+    }
+}
diff --git a/app/src/main/java/info/appdev/chartexample/custom/StackedBarsMarkerView.java b/app/src/main/java/info/appdev/chartexample/custom/StackedBarsMarkerView.java
deleted file mode 100644
index e56a8896a6..0000000000
--- a/app/src/main/java/info/appdev/chartexample/custom/StackedBarsMarkerView.java
+++ /dev/null
@@ -1,62 +0,0 @@
-
-package info.appdev.chartexample.custom;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.widget.TextView;
-
-import com.github.mikephil.charting.components.MarkerView;
-import com.github.mikephil.charting.data.BarEntry;
-import com.github.mikephil.charting.data.Entry;
-import com.github.mikephil.charting.highlight.Highlight;
-import com.github.mikephil.charting.utils.MPPointF;
-import com.github.mikephil.charting.utils.Utils;
-
-import info.appdev.chartexample.R;
-
-/**
- * Custom implementation of the MarkerView.
- *
- * @author Philipp Jahoda
- */
-@SuppressWarnings("unused")
-@SuppressLint("ViewConstructor")
-public class StackedBarsMarkerView extends MarkerView {
-
-    private TextView tvContent;
-
-    public StackedBarsMarkerView(Context context, int layoutResource) {
-        super(context, layoutResource);
-
-        tvContent = findViewById(R.id.tvContent);
-    }
-
-    // runs every time the MarkerView is redrawn, can be used to update the
-    // content (user-interface)
-    @Override
-    public void refreshContent(Entry e, Highlight highlight) {
-
-        if (e instanceof BarEntry) {
-
-            BarEntry be = (BarEntry) e;
-
-            if(be.getYVals() != null) {
-
-                // draw the stack value
-                tvContent.setText(Utils.formatNumber(be.getYVals()[highlight.getStackIndex()], 0, true));
-            } else {
-                tvContent.setText(Utils.formatNumber(be.getY(), 0, true));
-            }
-        } else {
-
-            tvContent.setText(Utils.formatNumber(e.getY(), 0, true));
-        }
-
-        super.refreshContent(e, highlight);
-    }
-
-    @Override
-    public MPPointF getOffset() {
-        return new MPPointF(-(getWidth() / 2), -getHeight());
-    }
-}
diff --git a/app/src/main/java/info/appdev/chartexample/custom/StackedBarsMarkerView.kt b/app/src/main/java/info/appdev/chartexample/custom/StackedBarsMarkerView.kt
new file mode 100644
index 0000000000..74bebe2a3c
--- /dev/null
+++ b/app/src/main/java/info/appdev/chartexample/custom/StackedBarsMarkerView.kt
@@ -0,0 +1,43 @@
+package info.appdev.chartexample.custom
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.widget.TextView
+import com.github.mikephil.charting.components.MarkerView
+import com.github.mikephil.charting.data.BarEntry
+import com.github.mikephil.charting.data.Entry
+import com.github.mikephil.charting.highlight.Highlight
+import com.github.mikephil.charting.utils.MPPointF
+import com.github.mikephil.charting.utils.Utils
+import info.appdev.chartexample.R
+
+/**
+ * Custom implementation of the MarkerView.
+ */
+@Suppress("unused")
+@SuppressLint("ViewConstructor")
+class StackedBarsMarkerView(context: Context?, layoutResource: Int) : MarkerView(context, layoutResource) {
+    private val tvContent: TextView = findViewById(R.id.tvContent)
+
+    // runs every time the MarkerView is redrawn, can be used to update the
+    // content (user-interface)
+    override fun refreshContent(entry: Entry, highlight: Highlight) {
+        if (entry is BarEntry) {
+
+            if (entry.yVals != null) {
+                // draw the stack value
+                tvContent.text = Utils.formatNumber(entry.yVals!![highlight.stackIndex], 0, true)
+            } else {
+                tvContent.text = Utils.formatNumber(entry.y, 0, true)
+            }
+        } else {
+            tvContent.text = Utils.formatNumber(entry.y, 0, true)
+        }
+
+        super.refreshContent(entry, highlight)
+    }
+
+    override fun getOffset(): MPPointF {
+        return MPPointF(-(width / 2).toFloat(), -height.toFloat())
+    }
+}
diff --git a/app/src/main/java/info/appdev/chartexample/custom/XYMarkerView.java b/app/src/main/java/info/appdev/chartexample/custom/XYMarkerView.java
deleted file mode 100644
index 7bebd17ded..0000000000
--- a/app/src/main/java/info/appdev/chartexample/custom/XYMarkerView.java
+++ /dev/null
@@ -1,53 +0,0 @@
-
-package info.appdev.chartexample.custom;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.widget.TextView;
-
-import com.github.mikephil.charting.components.MarkerView;
-import com.github.mikephil.charting.data.Entry;
-import com.github.mikephil.charting.formatter.IAxisValueFormatter;
-import com.github.mikephil.charting.highlight.Highlight;
-import com.github.mikephil.charting.utils.MPPointF;
-
-import java.text.DecimalFormat;
-
-import info.appdev.chartexample.R;
-
-/**
- * Custom implementation of the MarkerView.
- *
- * @author Philipp Jahoda
- */
-@SuppressLint("ViewConstructor")
-public class XYMarkerView extends MarkerView {
-
-    private final TextView tvContent;
-    private final IAxisValueFormatter xAxisValueFormatter;
-
-    private final DecimalFormat format;
-
-    public XYMarkerView(Context context, IAxisValueFormatter xAxisValueFormatter) {
-        super(context, R.layout.custom_marker_view);
-
-        this.xAxisValueFormatter = xAxisValueFormatter;
-        tvContent = findViewById(R.id.tvContent);
-        format = new DecimalFormat("###.0");
-    }
-
-    // runs every time the MarkerView is redrawn, can be used to update the
-    // content (user-interface)
-    @Override
-    public void refreshContent(Entry e, Highlight highlight) {
-
-        tvContent.setText(String.format("x: %s, y: %s", xAxisValueFormatter.getFormattedValue(e.getX(), null), format.format(e.getY())));
-
-        super.refreshContent(e, highlight);
-    }
-
-    @Override
-    public MPPointF getOffset() {
-        return new MPPointF(-(getWidth() / 2), -getHeight());
-    }
-}
diff --git a/app/src/main/java/info/appdev/chartexample/custom/XYMarkerView.kt b/app/src/main/java/info/appdev/chartexample/custom/XYMarkerView.kt
new file mode 100644
index 0000000000..a64f768c29
--- /dev/null
+++ b/app/src/main/java/info/appdev/chartexample/custom/XYMarkerView.kt
@@ -0,0 +1,33 @@
+package info.appdev.chartexample.custom
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.widget.TextView
+import com.github.mikephil.charting.components.MarkerView
+import com.github.mikephil.charting.data.Entry
+import com.github.mikephil.charting.formatter.IAxisValueFormatter
+import com.github.mikephil.charting.highlight.Highlight
+import com.github.mikephil.charting.utils.MPPointF
+import info.appdev.chartexample.R
+import java.text.DecimalFormat
+
+/**
+ * Custom implementation of the MarkerView.
+ */
+@SuppressLint("ViewConstructor")
+class XYMarkerView(context: Context?, private val xAxisValueFormatter: IAxisValueFormatter) : MarkerView(context, R.layout.custom_marker_view) {
+    private val tvContent: TextView = findViewById(R.id.tvContent)
+
+    private val format: DecimalFormat = DecimalFormat("###.0")
+
+    // runs every time the MarkerView is redrawn, can be used to update the content (user-interface)
+    override fun refreshContent(e: Entry, highlight: Highlight?) {
+        tvContent.text = String.format("x: %s, y: %s", xAxisValueFormatter.getFormattedValue(e.x, null), format.format(e.y.toDouble()))
+
+        super.refreshContent(e, highlight)
+    }
+
+    override fun getOffset(): MPPointF {
+        return MPPointF(-(width / 2).toFloat(), -height.toFloat())
+    }
+}