From 187fcf4abf51e1fd4cda12c57b8209701df853dc Mon Sep 17 00:00:00 2001
From: "Sanders (aider)" <Sanderrrs@gmail.com>
Date: Sun, 4 May 2025 14:39:18 +0300
Subject: [PATCH] fix: persist pie slice selection on tap

---
 .../lib/widgets/spending_pie_chart.dart       | 41 +++++++++++++------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/finance_app/lib/widgets/spending_pie_chart.dart b/finance_app/lib/widgets/spending_pie_chart.dart
index 2f00436..693735c 100644
--- a/finance_app/lib/widgets/spending_pie_chart.dart
+++ b/finance_app/lib/widgets/spending_pie_chart.dart
@@ -69,23 +69,23 @@ class SpendingPieChart extends StatelessWidget {
                           PieChartData(
                             // Handle touch events on the pie chart
                             pieTouchData: PieTouchData(
-                              touchCallback: (FlTouchEvent event, pieTouchResponse) {
-                                // Ignore events not related to interaction
-                                if (!event.isInterestedForInteractions ||
-                                    pieTouchResponse == null ||
-                                    pieTouchResponse.touchedSection == null) {
-                                  // If touch ends outside a section, deselect
-                                  if (event is FlPanEndEvent || event is FlTapUpEvent) {
+                              touchCallback: (FlTouchEvent event, PieTouchResponse? pieTouchResponse) {
+                                // We are only interested in TapUp events to trigger selection changes
+                                if (event is FlTapUpEvent) {
+                                  final section = pieTouchResponse?.touchedSection;
+                                  if (section != null) {
+                                    // Tap occurred ON a section
+                                    final touchedIndex = section.touchedSectionIndex;
+                                    // Toggle selection: if tapped section is already selected, deselect (-1), otherwise select it.
+                                    onSelectPieCategory(touchedIndex == selectedPieIndex ? -1 : touchedIndex);
+                                  } else {
+                                    // Tap occurred OUTSIDE any section
+                                    // Deselect if something was selected
                                     if (selectedPieIndex != -1) {
-                                      onSelectPieCategory(-1); // Deselect
+                                      onSelectPieCategory(-1);
                                     }
                                   }
-                                  return;
                                 }
-                                // Get the index of the touched section
-                                final touchedIndex = pieTouchResponse.touchedSection!.touchedSectionIndex;
-                                // Call the callback, toggling selection if the same slice is touched again
-                                onSelectPieCategory(touchedIndex == selectedPieIndex ? -1 : touchedIndex);
                               },
                             ),
                             borderData: FlBorderData(show: false), // No border around the chart
@@ -130,6 +130,11 @@ class SpendingPieChart extends StatelessWidget {
   // Builds the text displayed in the center when a slice is selected
   Widget _buildCenterText(BuildContext context, NumberFormat formatter) {
     final theme = Theme.of(context);
+    // Check if selectedPieIndex is valid before accessing categories
+    if (selectedPieIndex < 0 || selectedPieIndex >= categories.length) {
+      // Return an empty container or default text if index is invalid
+      return _buildDefaultCenterText(context, formatter);
+    }
     final selectedCategory = categories[selectedPieIndex];
     return Column(
       mainAxisAlignment: MainAxisAlignment.center,
@@ -189,6 +194,10 @@ class SpendingPieChart extends StatelessWidget {
     final isDark = Theme.of(context).brightness == Brightness.dark;
     final theme = Theme.of(context);
     final isSelected = index == selectedPieIndex; // Check if this item is selected
+    // Check if index is valid before accessing categories
+    if (index < 0 || index >= categories.length) {
+      return const SizedBox.shrink(); // Return empty if index is invalid
+    }
     final category = categories[index];
     // Calculate percentage, handle totalExpenses being zero
     final percentage = totalExpenses > 0 ? (category.amount / totalExpenses * 100) : 0.0;
@@ -256,6 +265,12 @@ class SpendingPieChart extends StatelessWidget {
     final isDark = Theme.of(context).brightness == Brightness.dark;
 
     return List.generate(categories.length, (i) {
+      // Check if index is valid before accessing categories
+      if (i < 0 || i >= categories.length) {
+        // This should ideally not happen if List.generate is used correctly,
+        // but adding a safeguard.
+        return PieChartSectionData(); // Return an empty section
+      }
       final isTouched = i == selectedPieIndex; // Check if this slice is selected
       // Make selected slice slightly larger
       final double radius = isTouched ? 65 : 55;