diff --git a/lib/src/chart/bar_chart/bar_chart_data.dart b/lib/src/chart/bar_chart/bar_chart_data.dart
index 3ef020e1d..63b1fe311 100644
--- a/lib/src/chart/bar_chart/bar_chart_data.dart
+++ b/lib/src/chart/bar_chart/bar_chart_data.dart
@@ -681,7 +681,7 @@ class BarTouchTooltipData with EquatableMixin {
 /// You can override [BarTouchTooltipData.getTooltipItem], it gives you
 /// [group], [groupIndex], [rod], and [rodIndex] that touch happened on,
 /// then you should and pass your custom [BarTooltipItem] to show inside the tooltip popup.
-typedef GetBarTooltipItem = BarTooltipItem Function(
+typedef GetBarTooltipItem = BarTooltipItem? Function(
   BarChartGroupData group,
   int groupIndex,
   BarChartRodData rod,
@@ -689,7 +689,7 @@ typedef GetBarTooltipItem = BarTooltipItem Function(
 );
 
 /// Default implementation for [BarTouchTooltipData.getTooltipItem].
-BarTooltipItem defaultBarTooltipItem(
+BarTooltipItem? defaultBarTooltipItem(
   BarChartGroupData group,
   int groupIndex,
   BarChartRodData rod,
diff --git a/lib/src/chart/bar_chart/bar_chart_painter.dart b/lib/src/chart/bar_chart/bar_chart_painter.dart
index 6670cd137..29de66e8d 100644
--- a/lib/src/chart/bar_chart/bar_chart_painter.dart
+++ b/lib/src/chart/bar_chart/bar_chart_painter.dart
@@ -484,6 +484,10 @@ class BarChartPainter extends AxisChartPainter<BarChartData> with TouchHandler<B
       barRodIndex,
     );
 
+    if (tooltipItem == null) {
+      return;
+    }
+
     final span = TextSpan(style: tooltipItem.textStyle, text: tooltipItem.text);
     final tp = TextPainter(
         text: span,
diff --git a/lib/src/chart/line_chart/line_chart_data.dart b/lib/src/chart/line_chart/line_chart_data.dart
index 93ee94677..6bbb6463e 100644
--- a/lib/src/chart/line_chart/line_chart_data.dart
+++ b/lib/src/chart/line_chart/line_chart_data.dart
@@ -1386,7 +1386,7 @@ class LineTouchData extends FlTouchData with EquatableMixin {
 /// in the given [barData], you should return a list of [TouchedSpotIndicatorData],
 /// length of this list should be equal to the [spotIndexes.length],
 /// each [TouchedSpotIndicatorData] determines the look of showing indicator.
-typedef GetTouchedSpotIndicator = List<TouchedSpotIndicatorData> Function(
+typedef GetTouchedSpotIndicator = List<TouchedSpotIndicatorData?> Function(
     LineChartBarData barData, List<int> spotIndexes);
 
 /// Default presentation of touched indicators.
diff --git a/lib/src/chart/line_chart/line_chart_painter.dart b/lib/src/chart/line_chart/line_chart_painter.dart
index 9c919d9c6..ad3471f08 100644
--- a/lib/src/chart/line_chart/line_chart_painter.dart
+++ b/lib/src/chart/line_chart/line_chart_painter.dart
@@ -277,6 +277,10 @@ class LineChartPainter extends AxisChartPainter<LineChartData>
       final index = barData.showingIndicators[i];
       final spot = barData.spots[index];
 
+      if (indicatorData == null) {
+        continue;
+      }
+
       final touchedSpot =
           Offset(getPixelX(spot.x, chartViewSize), getPixelY(spot.y, chartViewSize));
 
diff --git a/lib/src/chart/scatter_chart/scatter_chart_data.dart b/lib/src/chart/scatter_chart/scatter_chart_data.dart
index 5bc362d69..fb996c190 100644
--- a/lib/src/chart/scatter_chart/scatter_chart_data.dart
+++ b/lib/src/chart/scatter_chart/scatter_chart_data.dart
@@ -387,10 +387,10 @@ class ScatterTouchTooltipData with EquatableMixin {
 /// [touchedSpot] that touch happened on,
 /// then you should and pass your custom [ScatterTooltipItem]
 /// to show it inside the tooltip popup.
-typedef GetScatterTooltipItems = ScatterTooltipItem Function(ScatterSpot touchedSpot);
+typedef GetScatterTooltipItems = ScatterTooltipItem? Function(ScatterSpot touchedSpot);
 
 /// Default implementation for [ScatterTouchTooltipData.getTooltipItems].
-ScatterTooltipItem defaultScatterTooltipItem(ScatterSpot touchedSpot) {
+ScatterTooltipItem? defaultScatterTooltipItem(ScatterSpot touchedSpot) {
   final textStyle = TextStyle(
     color: touchedSpot.color,
     fontWeight: FontWeight.bold,
diff --git a/lib/src/chart/scatter_chart/scatter_chart_painter.dart b/lib/src/chart/scatter_chart/scatter_chart_painter.dart
index e208cf952..d63da56dc 100644
--- a/lib/src/chart/scatter_chart/scatter_chart_painter.dart
+++ b/lib/src/chart/scatter_chart/scatter_chart_painter.dart
@@ -227,9 +227,6 @@ class ScatterChartPainter extends AxisChartPainter<ScatterChartData>
   }
 
   void _drawSpots(CanvasWrapper canvasWrapper) {
-    if (data.scatterSpots == null) {
-      return;
-    }
     final viewSize = canvasWrapper.size;
     final chartUsableSize = getChartUsableDrawSize(viewSize);
     for (final scatterSpot in data.scatterSpots) {
diff --git a/lib/src/utils/lerp.dart b/lib/src/utils/lerp.dart
index 51b19c12b..3d45e761a 100644
--- a/lib/src/utils/lerp.dart
+++ b/lib/src/utils/lerp.dart
@@ -51,7 +51,7 @@ List<int>? lerpIntList(List<int>? a, List<int>? b, double t) => _lerpList(a, b,
 /// Lerps [int] list based on [t] value, check [Tween.lerp].
 int lerpInt(int a, int b, double t) => (a + (b - a) * t).round();
 
-double _lerpNonNullDouble(double a, double b, double t) => _lerpNonNullDouble(a, b, t);
+double _lerpNonNullDouble(double a, double b, double t) => lerpDouble(a, b, t)!;
 
 /// Lerps [FlSpot] list based on [t] value, check [Tween.lerp].
 List<FlSpot>? lerpFlSpotList(List<FlSpot>? a, List<FlSpot>? b, double t) =>