Kotlin chart data

MPChartLib/src/main/java/com/github/mikephil/charting/data/BarData.kt

@@ -33,13 +33,12 @@ class BarData : BarLineScatterCandleBubbleData<IBarDataSet> {
      */
     fun groupBars(fromX: Float, groupSpace: Float, barSpace: Float) {
         var fromX = fromX
-        val setCount = mDataSets.size
+        val setCount = dataSets?.size ?: 0
         if (setCount <= 1) {
             throw RuntimeException("BarData needs to hold at least 2 BarDataSets to allow grouping.")
         }
 
-        val max = getMaxEntryCountSet()
-        val maxEntryCount = max.entryCount
+        val maxEntryCount = maxEntryCountSet?.entryCount ?: 0
 
         val groupSpaceWidthHalf = groupSpace / 2f
         val barSpaceHalf = barSpace / 2f
@@ -51,22 +50,23 @@ class BarData : BarLineScatterCandleBubbleData<IBarDataSet> {
             val start = fromX
             fromX += groupSpaceWidthHalf
 
-            for (set in mDataSets) {
-                fromX += barSpaceHalf
-                fromX += barWidthHalf
+            dataSets?.let {
+                for (set in dataSets) {
+                    fromX += barSpaceHalf
+                    fromX += barWidthHalf
 
-                if (i < set.entryCount) {
-                    val entry = set.getEntryForIndex(i)
+                    if (i < set.entryCount) {
+                        val entry = set.getEntryForIndex(i)
 
-                    if (entry != null) {
-                        entry.x = fromX
+                        if (entry != null) {
+                            entry.x = fromX
+                        }
                     }
-                }
 
-                fromX += barWidthHalf
-                fromX += barSpaceHalf
+                    fromX += barWidthHalf
+                    fromX += barSpaceHalf
+                }
             }
-
             fromX += groupSpaceWidthHalf
             val end = fromX
             val innerInterval = end - start
@@ -85,6 +85,9 @@ class BarData : BarLineScatterCandleBubbleData<IBarDataSet> {
      * In case of grouped bars, this method returns the space an individual group of bar needs on the x-axis.
      */
     fun getGroupWidth(groupSpace: Float, barSpace: Float): Float {
-        return mDataSets.size * (this.barWidth + barSpace) + groupSpace
+        return if (dataSets == null)
+            0f
+        else
+            dataSets!!.size * (this.barWidth + barSpace) + groupSpace
     }
 }

MPChartLib/src/main/java/com/github/mikephil/charting/data/BarLineScatterCandleBubbleData.kt

@@ -1,14 +1,20 @@
 package com.github.mikephil.charting.data
 
 import com.github.mikephil.charting.interfaces.datasets.IBarLineScatterCandleBubbleDataSet
+import com.github.mikephil.charting.interfaces.datasets.IDataSet
 
 /**
  * Baseclass for all Line, Bar, Scatter, Candle and Bubble data.
  */
-abstract class BarLineScatterCandleBubbleData<T : IBarLineScatterCandleBubbleDataSet<out Entry>> : ChartData<T> {
+abstract class BarLineScatterCandleBubbleData<out T> : ChartData<@UnsafeVariance T>
+        where T : IDataSet<out Entry>,
+              T : IBarLineScatterCandleBubbleDataSet<out Entry> {
+
     constructor() : super()
 
-    constructor(vararg sets: T) : super(*sets)
+    @Suppress("UNCHECKED_CAST")
+    constructor(vararg sets: @UnsafeVariance T) : super(*sets)
 
-    constructor(sets: MutableList<T>) : super(sets)
+    @Suppress("UNCHECKED_CAST")
+    constructor(sets: MutableList<@UnsafeVariance T>) : super(sets)
 }

MPChartLib/src/main/java/com/github/mikephil/charting/data/BubbleData.kt

@@ -15,8 +15,10 @@ class BubbleData : BarLineScatterCandleBubbleData<IBubbleDataSet> {
      * for all DataSet objects this data object contains, in dp.
      */
     fun setHighlightCircleWidth(width: Float) {
-        for (set in mDataSets) {
-            set.highlightCircleWidth = width
+        if (dataSets != null) {
+            for (set in dataSets) {
+                set.highlightCircleWidth = width
+            }
         }
     }
 }