计算精度修复+长度限制

lib/pages/record_page.dart

@@ -3,6 +3,7 @@ import 'package:flutter/services.dart';
 import '../models/record.dart';
 import '../data/categories.dart';
 import 'package:uuid/uuid.dart';
+import 'package:decimal/decimal.dart';
 
 class RecordPage extends StatefulWidget {
   final Record? record;
@@ -31,6 +32,8 @@ class _RecordPageState extends State<RecordPage>
   String? _pendingValue; // 等待计算的第一个值
   String? _inputValue; // 当前输入的值
 
+  final d = (String s) => Decimal.parse(s);
+
   @override
   void initState() {
     super.initState();
@@ -83,7 +86,7 @@ class _RecordPageState extends State<RecordPage>
     }
     if (_amount <= 0) {
       ScaffoldMessenger.of(context).showSnackBar(
-        const SnackBar(content: Text('请输入金额')),
+        const SnackBar(content: Text('输入金额请大于0')),
       );
       return;
     }
@@ -101,7 +104,7 @@ class _RecordPageState extends State<RecordPage>
     Navigator.of(context).pop();
   }
 
-  /// 格式化显示金额
+  /// 显示金额
   String get _displayAmount {
     if (_pendingOperation != null ||
         _pendingValue != null ||
@@ -144,17 +147,18 @@ class _RecordPageState extends State<RecordPage>
   void _handleDelete() {
     setState(() {
       if (_inputValue != null) {
-        if(_inputValue!.length > 1){
+        if (_inputValue!.length > 1) {
           _inputValue = _inputValue!.substring(0, _inputValue!.length - 1);
-        }else{
+        } else {
           _inputValue = null;
         }
       } else if (_pendingOperation != null) {
         _pendingOperation = null;
       } else if (_pendingValue != null) {
-        if(_pendingValue!.length > 1){
+        if (_pendingValue!.length > 1) {
-          _pendingValue = _pendingValue!.substring(0, _pendingValue!.length - 1);
+          _pendingValue =
-        }else{
+              _pendingValue!.substring(0, _pendingValue!.length - 1);
+        } else {
           _pendingValue = null;
         }
       } else {
@@ -171,7 +175,6 @@ class _RecordPageState extends State<RecordPage>
       final newOperator = operator;
       _calculateResult();
 
-
       // 计算完成后，设置新的运算符
       setState(() {
         // 如果计算导致重置（结果为0），不添加新的运算符
@@ -181,7 +184,7 @@ class _RecordPageState extends State<RecordPage>
           _pendingOperation = newOperator;
         }
       });
-    } else if(_inputValue != null)  {
+    } else if (_inputValue != null) {
       // 正常设置运算符
       setState(() {
         _pendingOperation = operator;
@@ -195,22 +198,25 @@ class _RecordPageState extends State<RecordPage>
 
   /// 计算结果
   void _calculateResult() {
-    if (_pendingOperation != null &&
+
+    double result = 0;
+    if(_pendingValue == null && _inputValue== null){
+      return;
+    }
+    else if (_pendingOperation != null &&
         _pendingValue != null &&
         _inputValue != null) {
-      final currentValue = double.parse(_inputValue!);
-      double result;
     
       switch (_pendingOperation) {
         case '+':
-          result = double.parse(_pendingValue!) + currentValue;
+          result = (d(_pendingValue!) + d(_inputValue!)).toDouble();
           if (result == 0) {
             _resetToDefault();
             return;
           }
           break;
         case '-':
-          result = double.parse(_pendingValue!) - currentValue;
+          result = (d(_pendingValue!) - d(_inputValue!)).toDouble();
           if (result <= 0) {
             _resetToDefault();
             return;
@@ -219,15 +225,17 @@ class _RecordPageState extends State<RecordPage>
         default:
           return;
       }
+    } else {
+      result = double.parse(_inputValue ?? _pendingValue!);
+    } 
 
-      setState(() {
+    setState(() {
         // 格式化结果，去掉不必要的小数位
         _pendingValue = _formatNumberForDisplay(result);
         _amount = result;
         _pendingOperation = null;
         _inputValue = null;
       });
-    }
   }
 
   /// 重置到默认状态
@@ -260,6 +268,12 @@ class _RecordPageState extends State<RecordPage>
 
   /// 修改键盘按钮处理逻辑
   void _onKeyboardButtonPressed(String value) {
+    if (_inputBuffer.length >= 20 && value != '删除' && value != '保存'&& value != 'again'){
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('输入数字过大')),
+      );
+      return;
+    }
     switch (value) {
       case '删除':
         _handleDelete();

pubspec.yaml

@@ -35,6 +35,7 @@ dependencies:
   uuid: ^4.3.3  # 添加uuid包用于生成唯一ID
   sqflite: ^2.3.2  # 添加 SQLite 支持
   path: ^1.8.3     # 用于处理文件路径
+  decimal: ^3.0.0 # 处理计算精度
 
 
   # The following adds the Cupertino Icons font to your application.