Handled click in line_chart.

creky · Mar 19, 2021 · b6cc456 · b6cc456
1 parent 256d3d4
commit b6cc456
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Showing 5 changed files with 54 additions and 13 deletions.
diff --git a/example/lib/line_chart/samples/line_chart_sample3.dart b/example/lib/line_chart/samples/line_chart_sample3.dart
@@ -97,9 +97,10 @@ class _LineChartSample3State extends State<LineChartSample3> {
                         }).toList();
                       }),
                   touchCallback: (LineTouchResponse lineTouch) {
-                    if (lineTouch.lineBarSpots.length == 1 &&
-                        lineTouch.touchInput is! PointerExitEvent &&
-                        lineTouch.touchInput is! PointerUpEvent) {
+                    final desiredTouch = lineTouch.touchInput is! PointerExitEvent &&
+                        lineTouch.touchInput is! PointerUpEvent;
+
+                    if (desiredTouch && lineTouch.lineBarSpots != null) {
                       final value = lineTouch.lineBarSpots[0].x;
 
                       if (value == 0 || value == 6) {

diff --git a/lib/src/chart/line_chart/line_chart.dart b/lib/src/chart/line_chart/line_chart.dart
@@ -72,16 +72,17 @@ class _LineChartState extends AnimatedWidgetBaseState<LineChart> {
   void _handleBuiltInTouch(LineTouchResponse touchResponse) {
     widget.data.lineTouchData.touchCallback?.call(touchResponse);
 
-    if (touchResponse.touchInput is PointerDownEvent ||
+    final desiredTouch = touchResponse.touchInput is PointerDownEvent ||
         touchResponse.touchInput is PointerMoveEvent ||
-        touchResponse.touchInput is PointerHoverEvent) {
+        touchResponse.touchInput is PointerHoverEvent;
+    if (desiredTouch && touchResponse.lineBarSpots != null) {
       setState(() {
-        final sortedLineSpots = List.of(touchResponse.lineBarSpots);
+        final sortedLineSpots = List.of(touchResponse.lineBarSpots!);
         sortedLineSpots.sort((spot1, spot2) => spot2.y.compareTo(spot1.y));
 
         _showingTouchedIndicators.clear();
-        for (var i = 0; i < touchResponse.lineBarSpots.length; i++) {
-          final touchedBarSpot = touchResponse.lineBarSpots[i];
+        for (var i = 0; i < touchResponse.lineBarSpots!.length; i++) {
+          final touchedBarSpot = touchResponse.lineBarSpots![i];
           final barPos = touchedBarSpot.barIndex;
           _showingTouchedIndicators[barPos] = [touchedBarSpot.spotIndex];
         }

diff --git a/lib/src/chart/line_chart/line_chart_data.dart b/lib/src/chart/line_chart/line_chart_data.dart
@@ -1618,15 +1618,31 @@ typedef LineTouchCallback = void Function(LineTouchResponse);
 class LineTouchResponse extends BaseTouchResponse {
   /// touch happened on these spots
   /// (if a single line provided on the chart, [lineBarSpots]'s length will be 1 always)
-  final List<LineBarSpot> lineBarSpots;
+  final List<LineBarSpot>? lineBarSpots;
 
   /// If touch happens, [LineChart] processes it internally and
   /// passes out a list of [lineBarSpots] it gives you information about the touched spot.
   /// [touchInput] is the type of happened touch.
+  /// [clickHappened] will be true, if we detect a click event.
   LineTouchResponse(
     this.lineBarSpots,
     PointerEvent touchInput,
-  ) : super(touchInput);
+    bool clickHappened,
+  ) : super(touchInput, clickHappened);
+
+  /// Copies current [LineTouchResponse] to a new [LineTouchResponse],
+  /// and replaces provided values.
+  LineTouchResponse copyWith({
+    List<LineBarSpot>? lineBarSpots,
+    PointerEvent? touchInput,
+    bool? clickHappened,
+  }) {
+    return LineTouchResponse(
+      lineBarSpots ?? this.lineBarSpots,
+      touchInput ?? this.touchInput,
+      clickHappened ?? this.clickHappened,
+    );
+  }
 }
 
 /// It lerps a [LineChartData] to another [LineChartData] (handles animation for updating values)

diff --git a/lib/src/chart/line_chart/line_chart_painter.dart b/lib/src/chart/line_chart/line_chart_painter.dart
@@ -1370,7 +1370,7 @@ class LineChartPainter extends AxisChartPainter<LineChartData> {
   /// Processes [PointerEvent.localPosition] and checks
   /// the elements of the chart that are near the offset,
   /// then makes a [LineTouchResponse] from the elements that has been touched.
-  LineTouchResponse handleTouch(
+  List<LineBarSpot>? handleTouch(
     PointerEvent touchInput,
     Size size,
     PaintHolder<LineChartData> holder,
@@ -1393,7 +1393,7 @@ class LineChartPainter extends AxisChartPainter<LineChartData> {
       }
     }
 
-    return LineTouchResponse(touchedSpots, touchInput);
+    return touchedSpots.isEmpty ? null : touchedSpots;
   }
 
   /// find the nearest spot base on the touched offset

diff --git a/lib/src/chart/line_chart/line_chart_renderer.dart b/lib/src/chart/line_chart/line_chart_renderer.dart
@@ -73,6 +73,8 @@ class RenderLineChart extends RenderBox {
     return PaintHolder(data, targetData, textScale);
   }
 
+  List<LineBarSpot>? _lastTouchedSpots;
+
   @override
   void performLayout() {
     size = computeDryLayout(constraints);
@@ -97,6 +99,27 @@ class RenderLineChart extends RenderBox {
 
   @override
   void handleEvent(PointerEvent event, covariant BoxHitTestEntry entry) {
-    _touchCallback?.call(_painter.handleTouch(event, size, paintHolder));
+    if (_touchCallback == null) {
+      return;
+    }
+    var response = LineTouchResponse(null, event, false);
+
+    var touchedSpots = _painter.handleTouch(event, size, paintHolder);
+    if (touchedSpots == null || touchedSpots.isEmpty) {
+      _touchCallback!.call(response);
+      return;
+    }
+    response = response.copyWith(lineBarSpots: touchedSpots);
+
+    if (event is PointerDownEvent) {
+      _lastTouchedSpots = touchedSpots;
+    } else if (event is PointerUpEvent) {
+      if (_lastTouchedSpots == touchedSpots) {
+        response = response.copyWith(clickHappened: true);
+      }
+      _lastTouchedSpots = null;
+    }
+
+    _touchCallback!.call(response);
   }
 }