fix(treewide): migrate to sound null safety

Signed-off-by: Sphericalkat <me@kat.bio>

example/animated_pie_chart_example.dart

@@ -57,7 +57,7 @@ class _AnimatedPieChartExampleState extends State<AnimatedPieChartExample> {
     setState(() {
       sampleIndex++;
       List<CircularStackEntry> data = _quarterlyProfitPieData[sampleIndex % 3];
-      _chartKey.currentState.updateData(data);
+      _chartKey.currentState!.updateData(data);
     });
   }
 

example/animated_radial_chart_example.dart

@@ -17,13 +17,13 @@ class _AnimatedRadialChartExampleState extends State<AnimatedRadialChartExample>
   final _chartSize = const Size(200.0, 200.0);
 
   double value = 50.0;
-  Color labelColor = Colors.blue[200];
+  Color? labelColor = Colors.blue[200];
 
   void _increment() {
     setState(() {
       value += 10;
       List<CircularStackEntry> data = _generateChartData(value);
-      _chartKey.currentState.updateData(data);
+      _chartKey.currentState!.updateData(data);
     });
   }
 
@@ -31,12 +31,12 @@ class _AnimatedRadialChartExampleState extends State<AnimatedRadialChartExample>
     setState(() {
       value -= 10;
       List<CircularStackEntry> data = _generateChartData(value);
-      _chartKey.currentState.updateData(data);
+      _chartKey.currentState!.updateData(data);
     });
   }
 
   List<CircularStackEntry> _generateChartData(double value) {
-    Color dialColor = Colors.blue[200];
+    Color? dialColor = Colors.blue[200];
     if (value < 0) {
       dialColor = Colors.red[200];
     } else if (value < 50) {
@@ -78,7 +78,7 @@ class _AnimatedRadialChartExampleState extends State<AnimatedRadialChartExample>
   @override
   Widget build(BuildContext context) {
     TextStyle _labelStyle =
-        Theme.of(context).textTheme.headline6.merge(TextStyle(color: labelColor));
+        Theme.of(context).textTheme.headline6!.merge(TextStyle(color: labelColor));
 
     return Scaffold(
       appBar: AppBar(

example/animated_random_radial_chart_example.dart

@@ -19,7 +19,7 @@ class _RandomizedRadialChartExampleState extends State<RandomizedRadialChartExam
   final GlobalKey<AnimatedCircularChartState> _chartKey = GlobalKey<AnimatedCircularChartState>();
   final _chartSize = const Size(300.0, 300.0);
   final Math.Random random = Math.Random();
-  List<CircularStackEntry> data;
+  List<CircularStackEntry>? data;
 
   @override
   void initState() {
@@ -32,7 +32,7 @@ class _RandomizedRadialChartExampleState extends State<RandomizedRadialChartExam
   void _randomize() {
     setState(() {
       data = _generateRandomData();
-      _chartKey.currentState.updateData(data);
+      _chartKey.currentState!.updateData(data!);
     });
   }
 
@@ -41,7 +41,7 @@ class _RandomizedRadialChartExampleState extends State<RandomizedRadialChartExam
     List<CircularStackEntry> data = List.generate(stackCount, (i) {
       int segCount = random.nextInt(10);
       List<CircularSegmentEntry> segments = List.generate(segCount, (j) {
-        Color randomColor = ColorPalette.primary.random(random);
+        Color? randomColor = ColorPalette.primary.random(random);
         return CircularSegmentEntry(random.nextDouble(), randomColor);
       });
       return CircularStackEntry(segments);

example/color_palette.dart

@@ -3,7 +3,7 @@ import 'dart:math';
 import 'package:flutter/material.dart';
 
 class ColorPalette {
-  static final ColorPalette primary = ColorPalette(<Color>[
+  static final ColorPalette primary = ColorPalette(<Color?>[
     Colors.blue[400],
     Colors.blue[200],
     Colors.red[400],
@@ -21,15 +21,15 @@ class ColorPalette {
     Colors.black,
   ]);
 
-  ColorPalette(List<Color> colors) : _colors = colors {
+  ColorPalette(List<Color?> colors) : _colors = colors {
     assert(colors.isNotEmpty);
   }
 
-  final List<Color> _colors;
+  final List<Color?> _colors;
 
-  Color operator [](int index) => _colors[index % length];
+  Color? operator [](int index) => _colors[index % length];
 
   int get length => _colors.length;
 
-  Color random(Random random) => this[random.nextInt(length)];
+  Color? random(Random random) => this[random.nextInt(length)];
 }