diff --git a/app/src/main/java/info/nightscout/androidaps/plugins/insulin/ActivityGraph.java b/app/src/main/java/info/nightscout/androidaps/plugins/insulin/ActivityGraph.java
deleted file mode 100644
index ee682272a1..0000000000
--- a/app/src/main/java/info/nightscout/androidaps/plugins/insulin/ActivityGraph.java
+++ /dev/null
@@ -1,78 +0,0 @@
-package info.nightscout.androidaps.plugins.insulin;
-
-import android.content.Context;
-import android.graphics.Color;
-import android.util.AttributeSet;
-
-import com.jjoe64.graphview.GraphView;
-import com.jjoe64.graphview.series.DataPoint;
-import com.jjoe64.graphview.series.LineGraphSeries;
-
-import java.util.ArrayList;
-import java.util.List;
-
-import info.nightscout.androidaps.data.Iob;
-import info.nightscout.androidaps.db.Treatment;
-import info.nightscout.androidaps.interfaces.InsulinInterface;
-
-/**
- * Created by mike on 21.04.2017.
- */
-
-public class ActivityGraph extends GraphView {
-    Context context;
-
-    public ActivityGraph(Context context) {
-        super(context);
-        this.context = context;
-    }
-
-    public ActivityGraph(Context context, AttributeSet attrs) {
-        super(context, attrs);
-        this.context = context;
-    }
-
-    public void show(InsulinInterface insulin) {
-        removeAllSeries();
-        mSecondScale = null;
-        double dia = insulin.getDia();
-        int hours = (int) Math.floor(dia + 1);
-
-        Treatment t = new Treatment();
-        t.date = 0;
-        t.insulin = 1d;
-
-        LineGraphSeries<DataPoint> activitySeries = null;
-        LineGraphSeries<DataPoint> iobSeries = null;
-        List<DataPoint> activityArray = new ArrayList<>();
-        List<DataPoint> iobArray = new ArrayList<>();
-
-        for (long time = 0; time <= hours * 60 * 60 * 1000; time += 5 * 60 * 1000L) {
-            Iob iob = t.iobCalc(time, dia);
-            activityArray.add(new DataPoint(time / 60.0 / 1000, iob.activityContrib));
-            iobArray.add(new DataPoint(time / 60.0 / 1000, iob.iobContrib));
-        }
-
-        DataPoint[] activityDataPoints = new DataPoint[activityArray.size()];
-        activityDataPoints = activityArray.toArray(activityDataPoints);
-        addSeries(activitySeries = new LineGraphSeries<>(activityDataPoints));
-        activitySeries.setThickness(8);
-
-        getViewport().setXAxisBoundsManual(true);
-        getViewport().setMinX(0);
-        getViewport().setMaxX(hours * 60);
-        getGridLabelRenderer().setNumHorizontalLabels(hours + 1);
-        getGridLabelRenderer().setHorizontalAxisTitle("[min]");
-        getGridLabelRenderer().setVerticalLabelsColor(activitySeries.getColor());
-
-        DataPoint[] iobDataPoints = new DataPoint[iobArray.size()];
-        iobDataPoints = iobArray.toArray(iobDataPoints);
-        getSecondScale().addSeries(iobSeries = new LineGraphSeries<>(iobDataPoints));
-        iobSeries.setDrawBackground(true);
-        iobSeries.setColor(Color.MAGENTA);
-        iobSeries.setBackgroundColor(Color.argb(70, 255, 0, 255));
-        getSecondScale().setMinY(0);
-        getSecondScale().setMaxY(1);
-        getGridLabelRenderer().setVerticalLabelsSecondScaleColor(Color.MAGENTA);
-    }
-}
diff --git a/app/src/main/java/info/nightscout/androidaps/plugins/insulin/ActivityGraph.kt b/app/src/main/java/info/nightscout/androidaps/plugins/insulin/ActivityGraph.kt
new file mode 100644
index 0000000000..a6575c1886
--- /dev/null
+++ b/app/src/main/java/info/nightscout/androidaps/plugins/insulin/ActivityGraph.kt
@@ -0,0 +1,56 @@
+package info.nightscout.androidaps.plugins.insulin
+
+import android.content.Context
+import android.graphics.Color
+import android.util.AttributeSet
+import com.jjoe64.graphview.GraphView
+import com.jjoe64.graphview.series.DataPoint
+import com.jjoe64.graphview.series.LineGraphSeries
+import info.nightscout.androidaps.db.Treatment
+import info.nightscout.androidaps.interfaces.InsulinInterface
+import info.nightscout.androidaps.utils.T
+import java.util.*
+import kotlin.math.floor
+
+class ActivityGraph : GraphView {
+
+    constructor(context: Context) : super(context)
+
+    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)
+
+    fun show(insulin: InsulinInterface) {
+        removeAllSeries()
+        mSecondScale = null
+        val hours = floor(insulin.dia + 1).toLong()
+        val t = Treatment().also {
+            it.date = 0
+            it.insulin = 1.0
+        }
+        val activityArray: MutableList<DataPoint> = ArrayList()
+        val iobArray: MutableList<DataPoint> = ArrayList()
+        var time: Long = 0
+        while (time <= T.hours(hours).msecs()) {
+            val iob = t.iobCalc(time, insulin.dia)
+            activityArray.add(DataPoint(T.msecs(time).mins().toDouble(), iob.activityContrib))
+            iobArray.add(DataPoint(T.msecs(time).mins().toDouble(), iob.iobContrib))
+            time += T.mins(5).msecs()
+        }
+        addSeries(LineGraphSeries(Array(activityArray.size) { i -> activityArray[i] }).also {
+            it.thickness = 8
+            gridLabelRenderer.verticalLabelsColor = it.color
+        })
+        viewport.isXAxisBoundsManual = true
+        viewport.setMinX(0.0)
+        viewport.setMaxX((hours * 60).toDouble())
+        gridLabelRenderer.numHorizontalLabels = (hours + 1).toInt()
+        gridLabelRenderer.horizontalAxisTitle = "[min]"
+        secondScale.addSeries(LineGraphSeries(Array(iobArray.size) { i -> iobArray[i] }).also {
+            it.isDrawBackground = true
+            it.color = Color.MAGENTA
+            it.backgroundColor = Color.argb(70, 255, 0, 255)
+        })
+        secondScale.minY = 0.0
+        secondScale.maxY = 1.0
+        gridLabelRenderer.verticalLabelsSecondScaleColor = Color.MAGENTA
+    }
+}
\ No newline at end of file