Fix FlSpot.nullSpot at the first of list bug, #912.

imaNNeo · Feb 23, 2022 · 94e186c · 94e186c
1 parent cc3462a
commit 94e186c
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,6 @@
+## newVersion
+* **BUGFIX** Fix `FlSpot.nullSpot` at the first of list bug, #912.
+
 ## 0.45.0
 * **BUGFIX** Fix `clipData` implementation in ScatterChart and LineChart, #897.
 * **BUGFIX** Fix PieChart changing sections issue (we have disabled semantics for pieChart badgeWidgets), #861.

diff --git a/lib/src/chart/line_chart/line_chart_helper.dart b/lib/src/chart/line_chart/line_chart_helper.dart
@@ -1,8 +1,7 @@
 import 'package:equatable/equatable.dart';
+import 'package:fl_chart/fl_chart.dart';
 import 'package:fl_chart/src/utils/list_wrapper.dart';
 
-import 'line_chart_data.dart';
-
 /// Contains anything that helps LineChart works
 class LineChartHelper {
   /// Contains List of cached results, base on [List<LineChartBarData>]
@@ -32,10 +31,19 @@ class LineChartHelper {
       return LineChartMinMaxAxisValues(0, 0, 0, 0);
     }
 
-    var minX = lineBarData.spots[0].x;
-    var maxX = lineBarData.spots[0].x;
-    var minY = lineBarData.spots[0].y;
-    var maxY = lineBarData.spots[0].y;
+    final FlSpot firstValidSpot;
+    try {
+      firstValidSpot =
+          lineBarData.spots.firstWhere((element) => element != FlSpot.nullSpot);
+    } catch (e) {
+      // There is no valid spot
+      return LineChartMinMaxAxisValues(0, 0, 0, 0);
+    }
+
+    var minX = firstValidSpot.x;
+    var maxX = firstValidSpot.x;
+    var minY = firstValidSpot.y;
+    var maxY = firstValidSpot.y;
 
     for (var i = 0; i < lineBarsData.length; i++) {
       final barData = lineBarsData[i];

diff --git a/test/chart/line_chart/line_chart_helper_test.dart b/test/chart/line_chart/line_chart_helper_test.dart
@@ -56,5 +56,31 @@ void main() {
       final result2 = LineChartHelper.calculateMaxAxisValues(lineBarsClone);
       expect(result1, result2);
     });
+
+    test('Test null spot 1', () {
+      final lineBars = [
+        LineChartBarData(spots: [
+          FlSpot.nullSpot,
+          FlSpot.nullSpot,
+          FlSpot.nullSpot,
+          FlSpot.nullSpot,
+        ])
+      ];
+      final result1 = LineChartHelper.calculateMaxAxisValues(lineBars);
+      expect(result1, LineChartMinMaxAxisValues(0, 0, 0, 0));
+    });
+
+    test('Test null spot 2', () {
+      final lineBars = [
+        LineChartBarData(spots: [
+          FlSpot.nullSpot,
+          const FlSpot(-1, 5),
+          FlSpot.nullSpot,
+          const FlSpot(4, -3),
+        ])
+      ];
+      final result1 = LineChartHelper.calculateMaxAxisValues(lineBars);
+      expect(result1, LineChartMinMaxAxisValues(-1, 4, -3, 5));
+    });
   });
 }