feat: K线数据使用Decimal类型，防止数值精度丢失和溢出

flutter_monisuo/lib/providers/chart_provider.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter_chen_kchart/k_chart.dart';
+import 'package:decimal/decimal.dart';
 import '../models/candle.dart';
 
 /// 时间周期
@@ -83,15 +84,15 @@ class ChartProvider extends ChangeNotifier {
   List<Candle> _candles = [];
   List<Candle> get candles => _candles;
 
-  // k_chart 需要的数据格式
+  // k_chart 需要的数据格式（转换为 double）
   List<KLineEntity> get klineData {
     return _candles.map((c) {
       return KLineEntity.fromCustom(
-        open: c.open,
-        high: c.high,
-        low: c.low,
-        close: c.close,
-        vol: c.volume,
+        open: c.openDouble,
+        high: c.highDouble,
+        low: c.lowDouble,
+        close: c.closeDouble,
+        vol: c.volumeDouble,
         time: c.timestamp,
       );
     }).toList();
@@ -155,7 +156,7 @@ class ChartProvider extends ChangeNotifier {
     }
   }
 
-  /// 生成模拟 K 线数据
+  /// 生成模拟 K 线数据（使用 Decimal 防止精度丢失）
   List<Candle> _generateMockCandles() {
     final now = DateTime.now();
     final basePrice = _getBasePrice(_symbol);
@@ -176,13 +177,14 @@ class ChartProvider extends ChangeNotifier {
                             : i * 1440,
       ));
 
-      final random = (i * 17) % 100 / 100;
-      final change = basePrice * 0.02 * (random - 0.5);
+      // 使用 Decimal 进行安全计算
+      final random = Decimal.parse(((i * 17) % 100 / 100).toString());
+      final change = basePrice * Decimal.parse('0.02') * (random - Decimal.parse('0.5'));
       final open = basePrice + change;
-      final close = open + basePrice * 0.01 * ((i * 13) % 100 / 100 - 0.5);
-      final high = open > close ? open * 1.005 : close * 1.005;
-      final low = open < close ? open * 0.995 : close * 0.995;
-      final volume = 1000 + (i * 37) % 5000;
+      final close = open + basePrice * Decimal.parse('0.01') * (Decimal.parse(((i * 13) % 100 / 100).toString()) - Decimal.parse('0.5'));
+      final high = open > close ? open * Decimal.parse('1.005') : close * Decimal.parse('1.005');
+      final low = open < close ? open * Decimal.parse('0.995') : close * Decimal.parse('0.995');
+      final volume = Decimal.fromInt(1000 + (i * 37) % 5000);
 
       candles.add(Candle(
         timestamp: time.millisecondsSinceEpoch,
@@ -190,29 +192,29 @@ class ChartProvider extends ChangeNotifier {
         high: high,
         low: low,
         close: close,
-        volume: volume.toDouble(),
+        volume: volume,
       ));
     }
 
     return candles;
   }
 
-  double _getBasePrice(String symbol) {
+  Decimal _getBasePrice(String symbol) {
     switch (symbol.toUpperCase()) {
       case 'BTC':
-        return 42000.0;
+        return Decimal.parse('42000');
       case 'ETH':
-        return 2200.0;
+        return Decimal.parse('2200');
       case 'BNB':
-        return 300.0;
+        return Decimal.parse('300');
       case 'SOL':
-        return 100.0;
+        return Decimal.parse('100');
       case 'XRP':
-        return 0.5;
+        return Decimal.parse('0.5');
       case 'DOGE':
-        return 0.08;
+        return Decimal.parse('0.08');
       default:
-        return 100.0;
+        return Decimal.fromInt(100);
     }
   }
 }