🚀 Launch 1.0.0+4

android/app/src/main/AndroidManifest.xml

@@ -1,6 +1,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <application
-        android:label="simple_math_calc"
+        android:label="SimpleMathCalc"
         android:name="${applicationName}"
         android:icon="@mipmap/launcher_icon">
         <activity

lib/calculator.dart

@@ -0,0 +1,539 @@
+// === 在 abstract class Expr 中添加声明 ===
+import 'dart:math' show sqrt, cos, sin, tan;
+
+abstract class Expr {
+  Expr simplify();
+
+  /// 新增：对表达式进行“求值/数值化”——尽可能把可算的部分算出来
+  Expr evaluate();
+
+  @override
+  String toString();
+
+  MulExpr operator *(Expr other) => MulExpr(this, other);
+  AddExpr operator +(Expr other) => AddExpr(this, other);
+  SubExpr operator -(Expr other) => SubExpr(this, other);
+  DivExpr operator /(Expr other) => DivExpr(this, other);
+}
+
+// === IntExpr ===
+class IntExpr extends Expr {
+  final int value;
+  IntExpr(this.value);
+
+  @override
+  Expr simplify() => this;
+
+  @override
+  Expr evaluate() => this;
+
+  @override
+  String toString() => value.toString();
+}
+
+// === DoubleExpr ===
+class DoubleExpr extends Expr {
+  final double value;
+  DoubleExpr(this.value);
+
+  @override
+  Expr simplify() => this;
+
+  @override
+  Expr evaluate() => this;
+
+  @override
+  String toString() => value.toString();
+}
+
+// === FractionExpr.evaluate ===
+class FractionExpr extends Expr {
+  final int numerator;
+  final int denominator;
+
+  FractionExpr(this.numerator, this.denominator) {
+    if (denominator == 0) throw Exception("分母不能为0");
+  }
+
+  @override
+  Expr simplify() {
+    int g = _gcd(numerator.abs(), denominator.abs());
+    int n = numerator ~/ g;
+    int d = denominator ~/ g;
+
+    // 分母负数转移到分子
+    if (d < 0) {
+      n = -n;
+      d = -d;
+    }
+
+    if (d == 1) return IntExpr(n); // 化简成整数
+    return FractionExpr(n, d);
+  }
+
+  @override
+  Expr evaluate() => simplify();
+
+  @override
+  String toString() => "$numerator/$denominator";
+}
+
+// === AddExpr.evaluate: 把可算的合并（整数、分数、以及同类 sqrt 项） ===
+class AddExpr extends Expr {
+  final Expr left, right;
+  AddExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator + r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.value * r.denominator + r.numerator,
+        r.denominator,
+      ).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(
+        l.numerator + r.value * l.denominator,
+        l.denominator,
+      ).simplify();
+    }
+
+    return AddExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    // 纯整数相加 -> 整数
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value + r.value);
+    }
+
+    // 分数相加 / 分数与整数相加
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator + r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.value * r.denominator + r.numerator,
+        r.denominator,
+      ).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(
+        l.numerator + r.value * l.denominator,
+        l.denominator,
+      ).simplify();
+    }
+
+    // 合并同类的 sqrt 项: a*sqrt(X) + b*sqrt(X) = (a+b)*sqrt(X)
+    var a = _asSqrtTerm(l);
+    var b = _asSqrtTerm(r);
+    if (a != null && b != null && a.inner.toString() == b.inner.toString()) {
+      return MulExpr(IntExpr(a.coef + b.coef), SqrtExpr(a.inner)).simplify();
+    }
+
+    return AddExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left + $right)";
+}
+
+// === SubExpr.evaluate 类似 AddExpr，但做减法 ===
+class SubExpr extends Expr {
+  final Expr left, right;
+  SubExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value - r.value);
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator - r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    return SubExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value - r.value);
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator - r.numerator * l.denominator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.value * r.denominator - r.numerator,
+        r.denominator,
+      ).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(
+        l.numerator - r.value * l.denominator,
+        l.denominator,
+      ).simplify();
+    }
+
+    // 处理同类 sqrt 项: a*sqrt(X) - b*sqrt(X) = (a-b)*sqrt(X)
+    var a = _asSqrtTerm(l);
+    var b = _asSqrtTerm(r);
+    if (a != null && b != null && a.inner.toString() == b.inner.toString()) {
+      return MulExpr(IntExpr(a.coef - b.coef), SqrtExpr(a.inner)).simplify();
+    }
+
+    return SubExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left - $right)";
+}
+
+// === MulExpr.evaluate ===
+class MulExpr extends Expr {
+  final Expr left, right;
+  MulExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is IntExpr && l.value == 1) return r;
+    if (r is IntExpr && r.value == 1) return l;
+    if (l is IntExpr && l.value == -1) return SubExpr(IntExpr(0), r).simplify();
+    if (r is IntExpr && r.value == -1) return SubExpr(IntExpr(0), l).simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value * r.value);
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator * r.value, l.denominator).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.numerator, r.denominator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.numerator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+    if (l is SqrtExpr && r is FractionExpr) {
+      return FractionExpr(1, r.denominator).simplify() *
+          MulExpr(l, IntExpr(r.numerator)).simplify();
+    }
+
+    return MulExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    if (l is IntExpr && l.value == 1) return r;
+    if (r is IntExpr && r.value == 1) return l;
+    if (l is IntExpr && l.value == -1) return SubExpr(IntExpr(0), r).simplify();
+    if (r is IntExpr && r.value == -1) return SubExpr(IntExpr(0), l).simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return IntExpr(l.value * r.value);
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator * r.value, l.denominator).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.numerator, r.denominator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.numerator,
+        l.denominator * r.denominator,
+      ).simplify();
+    }
+
+    // sqrt * sqrt: sqrt(a)*sqrt(a) = a
+    if (l is SqrtExpr &&
+        r is SqrtExpr &&
+        l.inner.toString() == r.inner.toString()) {
+      return l.inner.simplify();
+    }
+
+    // int * sqrt -> 保留形式，之后 simplify() 再处理约分
+    if ((l is IntExpr && r is SqrtExpr) || (l is SqrtExpr && r is IntExpr)) {
+      return MulExpr(l, r).simplify();
+    }
+
+    return MulExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left * $right)";
+}
+
+// === DivExpr.evaluate ===
+class DivExpr extends Expr {
+  final Expr left, right;
+  DivExpr(this.left, this.right);
+
+  @override
+  Expr simplify() {
+    var l = left.simplify();
+    var r = right.simplify();
+
+    if (l is IntExpr && r is IntExpr) {
+      return FractionExpr(l.value, r.value).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator, l.denominator * r.value).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.denominator, r.numerator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator,
+        l.denominator * r.numerator,
+      ).simplify();
+    }
+    if (l is MulExpr &&
+        l.left is IntExpr &&
+        l.right is SqrtExpr &&
+        r is IntExpr) {
+      int coeff = (l.left as IntExpr).value;
+      int denom = r.value;
+      int g = _gcd(coeff.abs(), denom.abs());
+      return MulExpr(
+        IntExpr(coeff ~/ g),
+        DivExpr(l.right, IntExpr(denom ~/ g)).simplify(),
+      ).simplify();
+    }
+    return DivExpr(l, r);
+  }
+
+  @override
+  Expr evaluate() {
+    var l = left.evaluate();
+    var r = right.evaluate();
+
+    if (l is IntExpr && r is IntExpr) {
+      return FractionExpr(l.value, r.value).simplify();
+    }
+    if (l is FractionExpr && r is IntExpr) {
+      return FractionExpr(l.numerator, l.denominator * r.value).simplify();
+    }
+    if (l is IntExpr && r is FractionExpr) {
+      return FractionExpr(l.value * r.denominator, r.numerator).simplify();
+    }
+    if (l is FractionExpr && r is FractionExpr) {
+      return FractionExpr(
+        l.numerator * r.denominator,
+        l.denominator * r.numerator,
+      ).simplify();
+    }
+
+    // handle (k * sqrt(X)) / d 约分
+    if (l is MulExpr &&
+        l.left is IntExpr &&
+        l.right is SqrtExpr &&
+        r is IntExpr) {
+      int coeff = (l.left as IntExpr).value;
+      int denom = r.value;
+      int g = _gcd(coeff.abs(), denom.abs());
+      return MulExpr(
+        IntExpr(coeff ~/ g),
+        DivExpr(l.right, IntExpr(denom ~/ g)).evaluate(),
+      ).evaluate();
+    }
+
+    return DivExpr(l, r);
+  }
+
+  @override
+  String toString() => "($left / $right)";
+}
+
+// === SqrtExpr.evaluate ===
+class SqrtExpr extends Expr {
+  final Expr inner;
+  SqrtExpr(this.inner);
+
+  @override
+  Expr simplify() {
+    var i = inner.simplify();
+    if (i is IntExpr) {
+      int n = i.value;
+      int root = sqrt(n).floor();
+      if (root * root == n) {
+        return IntExpr(root); // 完全平方数
+      }
+      // 尝试拆分 sqrt，比如 sqrt(8) = 2*sqrt(2)
+      for (int k = root; k > 1; k--) {
+        if (n % (k * k) == 0) {
+          return MulExpr(
+            IntExpr(k),
+            SqrtExpr(IntExpr(n ~/ (k * k))),
+          ).simplify();
+        }
+      }
+    }
+    return SqrtExpr(i);
+  }
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      int n = i.value;
+      int root = sqrt(n).floor();
+      if (root * root == n) return IntExpr(root);
+      // 拆平方因子并返回 k * sqrt(remain)
+      for (int k = root; k > 1; k--) {
+        if (n % (k * k) == 0) {
+          return MulExpr(
+            IntExpr(k),
+            SqrtExpr(IntExpr(n ~/ (k * k))),
+          ).evaluate();
+        }
+      }
+    }
+    return SqrtExpr(i);
+  }
+
+  @override
+  String toString() => "sqrt($inner)";
+}
+
+// === CosExpr ===
+class CosExpr extends Expr {
+  final Expr inner;
+  CosExpr(this.inner);
+
+  @override
+  Expr simplify() => CosExpr(inner.simplify());
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      return DoubleExpr(cos(i.value.toDouble()));
+    }
+    if (i is FractionExpr) {
+      return DoubleExpr(cos(i.numerator / i.denominator));
+    }
+    if (i is DoubleExpr) {
+      return DoubleExpr(cos(i.value));
+    }
+    return CosExpr(i);
+  }
+
+  @override
+  String toString() => "cos($inner)";
+}
+
+// === SinExpr ===
+class SinExpr extends Expr {
+  final Expr inner;
+  SinExpr(this.inner);
+
+  @override
+  Expr simplify() => SinExpr(inner.simplify());
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      return DoubleExpr(sin(i.value.toDouble()));
+    }
+    if (i is FractionExpr) {
+      return DoubleExpr(sin(i.numerator / i.denominator));
+    }
+    if (i is DoubleExpr) {
+      return DoubleExpr(sin(i.value));
+    }
+    return SinExpr(i);
+  }
+
+  @override
+  String toString() => "sin($inner)";
+}
+
+// === TanExpr ===
+class TanExpr extends Expr {
+  final Expr inner;
+  TanExpr(this.inner);
+
+  @override
+  Expr simplify() => TanExpr(inner.simplify());
+
+  @override
+  Expr evaluate() {
+    var i = inner.evaluate();
+    if (i is IntExpr) {
+      return DoubleExpr(tan(i.value.toDouble()));
+    }
+    if (i is FractionExpr) {
+      return DoubleExpr(tan(i.numerator / i.denominator));
+    }
+    if (i is DoubleExpr) {
+      return DoubleExpr(tan(i.value));
+    }
+    return TanExpr(i);
+  }
+
+  @override
+  String toString() => "tan($inner)";
+}
+
+// === 辅助：识别 a * sqrt(X) 形式 ===
+class _SqrtTerm {
+  final int coef;
+  final Expr inner;
+  _SqrtTerm(this.coef, this.inner);
+}
+
+_SqrtTerm? _asSqrtTerm(Expr e) {
+  if (e is SqrtExpr) return _SqrtTerm(1, e.inner);
+  if (e is MulExpr) {
+    // 可能为 Int * Sqrt or Sqrt * Int
+    if (e.left is IntExpr && e.right is SqrtExpr) {
+      return _SqrtTerm((e.left as IntExpr).value, (e.right as SqrtExpr).inner);
+    }
+    if (e.right is IntExpr && e.left is SqrtExpr) {
+      return _SqrtTerm((e.right as IntExpr).value, (e.left as SqrtExpr).inner);
+    }
+  }
+  return null;
+}
+
+/// 辗转相除法求 gcd
+int _gcd(int a, int b) => b == 0 ? a : _gcd(b, a % b);

lib/parser.dart

@@ -0,0 +1,111 @@
+import 'package:simple_math_calc/calculator.dart';
+
+class Parser {
+  final String input;
+  int pos = 0;
+
+  Parser(this.input);
+
+  bool get isEnd => pos >= input.length;
+  String get current => isEnd ? '' : input[pos];
+
+  void eat() => pos++;
+
+  void skipSpaces() {
+    while (!isEnd && input[pos] == ' ') {
+      eat();
+    }
+  }
+
+  Expr parse() => parseAdd();
+
+  Expr parseAdd() {
+    var expr = parseMul();
+    skipSpaces();
+    while (!isEnd && (current == '+' || current == '-')) {
+      var op = current;
+      eat();
+      var right = parseMul();
+      expr = op == '+' ? AddExpr(expr, right) : SubExpr(expr, right);
+      skipSpaces();
+    }
+    return expr;
+  }
+
+  Expr parseMul() {
+    var expr = parseAtom();
+    skipSpaces();
+    while (!isEnd && (current == '*' || current == '/')) {
+      var op = current;
+      eat();
+      var right = parseAtom();
+      if (op == '*') {
+        expr = MulExpr(expr, right);
+      } else {
+        expr = DivExpr(expr, right);
+      }
+      skipSpaces();
+    }
+    return expr;
+  }
+
+  Expr parseAtom() {
+    skipSpaces();
+    if (current == '(') {
+      eat();
+      var expr = parse();
+      if (current != ')') throw Exception("缺少 )");
+      eat();
+      return expr;
+    }
+
+    if (input.startsWith("sqrt", pos)) {
+      pos += 4;
+      if (current != '(') throw Exception("sqrt 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("sqrt 缺少 )");
+      eat();
+      return SqrtExpr(inner);
+    }
+
+    if (input.startsWith("cos", pos)) {
+      pos += 3;
+      if (current != '(') throw Exception("cos 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("cos 缺少 )");
+      eat();
+      return CosExpr(inner);
+    }
+
+    if (input.startsWith("sin", pos)) {
+      pos += 3;
+      if (current != '(') throw Exception("sin 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("sin 缺少 )");
+      eat();
+      return SinExpr(inner);
+    }
+
+    if (input.startsWith("tan", pos)) {
+      pos += 3;
+      if (current != '(') throw Exception("tan 缺少 (");
+      eat();
+      var inner = parse();
+      if (current != ')') throw Exception("tan 缺少 )");
+      eat();
+      return TanExpr(inner);
+    }
+
+    // 解析整数
+    var buf = '';
+    while (!isEnd && RegExp(r'\d').hasMatch(current)) {
+      buf += current;
+      eat();
+    }
+    if (buf.isEmpty) throw Exception("无法解析: $current");
+    return IntExpr(int.parse(buf));
+  }
+}

lib/screens/calculator_home_page.dart

@@ -1,9 +1,9 @@
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
-import 'package:google_fonts/google_fonts.dart';
 import 'package:latext/latext.dart';
 import 'package:simple_math_calc/models/calculation_step.dart';
 import 'package:simple_math_calc/solver.dart';
+import 'package:fl_chart/fl_chart.dart';
+import 'package:math_expressions/math_expressions.dart' as math_expressions;
 import 'dart:math';
 
 class CalculatorHomePage extends StatefulWidget {
@@ -20,25 +20,141 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
 
   CalculationResult? _result;
   bool _isLoading = false;
-  bool _isInputFocused = false;
+  double _zoomFactor = 1.0;
 
   @override
   void initState() {
     super.initState();
     _focusNode = FocusNode();
-    _focusNode.addListener(() {
-      setState(() {
-        _isInputFocused = _focusNode.hasFocus;
-      });
-    });
+    _controller.addListener(_onTextChanged);
   }
 
   @override
   void dispose() {
+    _controller.removeListener(_onTextChanged);
     _focusNode.dispose();
     super.dispose();
   }
 
+  void _onTextChanged() {
+    setState(() {});
+  }
+
+  /// 生成函数图表的点
+  List<FlSpot> _generatePlotPoints(String expression, double zoomFactor) {
+    try {
+      // 如果是方程，取左边作为函数
+      String functionExpr = expression;
+      if (expression.contains('=')) {
+        functionExpr = expression.split('=')[0].trim();
+      }
+
+      // 如果表达式不包含 x，返回空列表
+      if (!functionExpr.contains('x') && !functionExpr.contains('X')) {
+        return [];
+      }
+
+      // 预处理表达式，确保格式正确
+      functionExpr = functionExpr.replaceAll(' ', '');
+
+      // 在数字和变量之间插入乘号
+      functionExpr = functionExpr.replaceAllMapped(
+        RegExp(r'(\d)([a-zA-Z])'),
+        (match) => '${match.group(1)}*${match.group(2)}',
+      );
+
+      // 在变量和数字之间插入乘号 (如 x2 -> x*2)
+      functionExpr = functionExpr.replaceAllMapped(
+        RegExp(r'([a-zA-Z])(\d)'),
+        (match) => '${match.group(1)}*${match.group(2)}',
+      );
+
+      // 解析表达式
+      final parser = math_expressions.ShuntingYardParser();
+      final expr = parser.parse(functionExpr);
+
+      // 创建变量 x
+      final x = math_expressions.Variable('x');
+
+      // 根据缩放因子动态调整范围和步长
+      final range = 10.0 * zoomFactor;
+      final step = max(0.05, 0.2 / zoomFactor); // 缩放时步长更小，放大时步长更大
+
+      // 生成点
+      List<FlSpot> points = [];
+      for (double i = -range; i <= range; i += step) {
+        try {
+          final context = math_expressions.ContextModel()
+            ..bindVariable(x, math_expressions.Number(i));
+          final evaluator = math_expressions.RealEvaluator(context);
+          final y = evaluator.evaluate(expr);
+
+          if (y.isFinite && !y.isNaN) {
+            points.add(FlSpot(i, y.toDouble()));
+          }
+        } catch (e) {
+          // 跳过无法计算的点
+          continue;
+        }
+      }
+
+      // 如果没有足够的点，返回空列表
+      if (points.length < 2) {
+        debugPrint('Generated ${points.length} dots');
+        return [];
+      }
+
+      // 排序点按 x 值
+      points.sort((a, b) => a.x.compareTo(b.x));
+
+      debugPrint(
+        'Generated ${points.length} dots with zoom factor $zoomFactor',
+      );
+      return points;
+    } catch (e) {
+      debugPrint('Error generating plot points: $e');
+      return [];
+    }
+  }
+
+  /// 计算图表的数据范围
+  ({double minX, double maxX, double minY, double maxY}) _calculateChartBounds(
+    List<FlSpot> points,
+    double zoomFactor,
+  ) {
+    if (points.isEmpty) {
+      return (
+        minX: -10 * zoomFactor,
+        maxX: 10 * zoomFactor,
+        minY: -50 * zoomFactor,
+        maxY: 50 * zoomFactor,
+      );
+    }
+
+    double minX = points.first.x;
+    double maxX = points.first.x;
+    double minY = points.first.y;
+    double maxY = points.first.y;
+
+    for (final point in points) {
+      minX = min(minX, point.x);
+      maxX = max(maxX, point.x);
+      minY = min(minY, point.y);
+      maxY = max(maxY, point.y);
+    }
+
+    // 添加边距
+    final xPadding = (maxX - minX) * 0.1;
+    final yPadding = (maxY - minY) * 0.1;
+
+    return (
+      minX: minX - xPadding,
+      maxX: maxX + xPadding,
+      minY: minY - yPadding,
+      maxY: maxY + yPadding,
+    );
+  }
+
   void _solveEquation() {
     if (_controller.text.isEmpty) {
       return;
@@ -69,21 +185,23 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
     }
   }
 
-  void _insertSymbol(String symbol) {
-    final text = _controller.text;
-    final selection = _controller.selection;
-    final newText = text.replaceRange(selection.start, selection.end, symbol);
-    _controller.text = newText;
-    _controller.selection = TextSelection.collapsed(
-      offset: selection.start + symbol.length,
-    );
+  void _zoomIn() {
+    setState(() {
+      _zoomFactor = (_zoomFactor * 0.8).clamp(0.1, 10.0);
+    });
+  }
+
+  void _zoomOut() {
+    setState(() {
+      _zoomFactor = (_zoomFactor * 1.25).clamp(0.1, 10.0);
+    });
   }
 
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: const Text('方程与表达式计算器'),
+        title: const Text('计算器'),
         centerTitle: false,
         leading: const Icon(Icons.calculate_outlined),
       ),
@@ -105,12 +223,10 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
                       floatingLabelAlignment: FloatingLabelAlignment.center,
                       hintText: '例如: 2x^2 - 8x + 6 = 0',
                     ),
-                    keyboardType: kIsWeb
-                        ? TextInputType.numberWithOptions(
-                            signed: true,
-                            decimal: true,
-                          )
-                        : TextInputType.number,
+                    keyboardType: TextInputType.numberWithOptions(
+                      signed: true,
+                      decimal: true,
+                    ),
                     onSubmitted: (_) => _solveEquation(),
                   ),
                 ),
@@ -128,7 +244,6 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
                 ? const Center(child: Text('请输入方程开始计算'))
                 : buildResultView(_result!),
           ),
-          if (_isInputFocused) _buildToolbar(),
         ],
       ),
     );
@@ -239,155 +354,107 @@ class _CalculatorHomePageState extends State<CalculatorHomePage> {
             ),
           ),
         ),
+        const SizedBox(height: 16),
+        Card(
+          child: Padding(
+            padding: const EdgeInsets.all(16.0),
+            child: Column(
+              children: [
+                Row(
+                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                  children: [
+                    Padding(
+                      padding: const EdgeInsets.only(left: 4),
+                      child: Text(
+                        '函数图像',
+                        style: Theme.of(context).textTheme.titleMedium,
+                      ),
+                    ),
+                    Row(
+                      mainAxisAlignment: MainAxisAlignment.center,
+                      children: [
+                        IconButton(
+                          onPressed: _zoomIn,
+                          icon: Icon(Icons.zoom_in),
+                          tooltip: '放大',
+                          padding: EdgeInsets.zero,
+                          visualDensity: VisualDensity.compact,
+                        ),
+                        IconButton(
+                          onPressed: _zoomOut,
+                          icon: Icon(Icons.zoom_out),
+                          tooltip: '缩小',
+                          padding: EdgeInsets.zero,
+                          visualDensity: VisualDensity.compact,
+                        ),
+                      ],
+                    ),
+                  ],
+                ),
+                const SizedBox(height: 24),
+                SizedBox(
+                  height: 340,
+                  child: Builder(
+                    builder: (context) {
+                      final points = _generatePlotPoints(
+                        _controller.text,
+                        _zoomFactor,
+                      );
+                      final bounds = _calculateChartBounds(points, _zoomFactor);
+
+                      return LineChart(
+                        LineChartData(
+                          gridData: FlGridData(show: true),
+                          titlesData: FlTitlesData(
+                            leftTitles: AxisTitles(
+                              sideTitles: SideTitles(
+                                showTitles: true,
+                                reservedSize: 40,
+                              ),
+                            ),
+                            bottomTitles: AxisTitles(
+                              sideTitles: SideTitles(
+                                showTitles: true,
+                                reservedSize: 30,
+                              ),
+                            ),
+                            topTitles: AxisTitles(
+                              sideTitles: SideTitles(showTitles: false),
+                            ),
+                            rightTitles: AxisTitles(
+                              sideTitles: SideTitles(showTitles: false),
+                            ),
+                          ),
+                          borderData: FlBorderData(
+                            show: true,
+                            border: Border.all(
+                              color: Theme.of(context).colorScheme.outline,
+                            ),
+                          ),
+                          lineBarsData: [
+                            LineChartBarData(
+                              spots: points,
+                              isCurved: true,
+                              color: Theme.of(context).colorScheme.primary,
+                              barWidth: 3,
+                              belowBarData: BarAreaData(show: false),
+                              dotData: FlDotData(show: false),
+                            ),
+                          ],
+                          minX: bounds.minX,
+                          maxX: bounds.maxX,
+                          minY: bounds.minY,
+                          maxY: bounds.maxY,
+                        ),
+                      );
+                    },
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
       ],
     );
   }
-
-  Widget _buildToolbar() {
-    return Material(
-      elevation: 8,
-      child: Padding(
-        padding: const EdgeInsets.symmetric(horizontal: 8.0, vertical: 8),
-        child: Column(
-          mainAxisSize: MainAxisSize.min,
-          children: [
-            Row(
-              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-              spacing: 8,
-              children: [
-                Expanded(
-                  child: Tooltip(
-                    message: '左括号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('('),
-                      child: Text('(', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '右括号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol(')'),
-                      child: Text(')', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '幂符号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('^'),
-                      child: Text('^', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '平方',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('^2'),
-                      child: Text('²', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '未知数',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('x'),
-                      child: Text('x', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '未知数二号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('y'),
-                      child: Text('y', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-              ],
-            ),
-            const SizedBox(height: 8),
-            Row(
-              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-              spacing: 8,
-              children: [
-                Expanded(
-                  child: Tooltip(
-                    message: '加法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('+'),
-                      child: Text('+', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '减法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('-'),
-                      child: Text('-', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '乘法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('*'),
-                      child: Text('*', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '除法',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('/'),
-                      child: Text('/', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '小数点',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('.'),
-                      child: Text('.', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-                Expanded(
-                  child: Tooltip(
-                    message: '等于号',
-                    child: FilledButton.tonal(
-                      onPressed: () => _insertSymbol('='),
-                      child: Text('=', style: GoogleFonts.robotoMono()),
-                    ),
-                  ),
-                ),
-              ],
-            ),
-            if (!kIsWeb) const SizedBox(height: 8),
-            if (!kIsWeb)
-              Row(
-                children: [
-                  Expanded(
-                    child: FilledButton.icon(
-                      icon: const Icon(Icons.keyboard_hide),
-                      onPressed: () => _focusNode.unfocus(),
-                      label: Text('收起键盘'),
-                    ),
-                  ),
-                ],
-              ),
-          ],
-        ),
-      ),
-    );
-  }
 }

pubspec.lock

@@ -1,6 +1,22 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  _fe_analyzer_shared:
+    dependency: transitive
+    description:
+      name: _fe_analyzer_shared
+      sha256: da0d9209ca76bde579f2da330aeb9df62b6319c834fa7baae052021b0462401f
+      url: "https://pub.dev"
+    source: hosted
+    version: "85.0.0"
+  analyzer:
+    dependency: transitive
+    description:
+      name: analyzer
+      sha256: "974859dc0ff5f37bc4313244b3218c791810d03ab3470a579580279ba971a48d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.7.1"
   ansicolor:
     dependency: transitive
     description:
@@ -57,6 +73,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.4"
+  cli_config:
+    dependency: transitive
+    description:
+      name: cli_config
+      sha256: ac20a183a07002b700f0c25e61b7ee46b23c309d76ab7b7640a028f18e4d99ec
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.0"
   cli_util:
     dependency: transitive
     description:
@@ -81,6 +105,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.19.1"
+  convert:
+    dependency: transitive
+    description:
+      name: convert
+      sha256: b30acd5944035672bc15c6b7a8b47d773e41e2f17de064350988c5d02adb1c68
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.2"
+  coverage:
+    dependency: transitive
+    description:
+      name: coverage
+      sha256: "5da775aa218eaf2151c721b16c01c7676fbfdd99cebba2bf64e8b807a28ff94d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.15.0"
   crypto:
     dependency: transitive
     description:
@@ -105,6 +145,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.8"
+  equatable:
+    dependency: transitive
+    description:
+      name: equatable
+      sha256: "567c64b3cb4cf82397aac55f4f0cbd3ca20d77c6c03bedbc4ceaddc08904aef7"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.7"
   fake_async:
     dependency: transitive
     description:
@@ -121,6 +169,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.4"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      sha256: a3b4f84adafef897088c160faf7dfffb7696046cb13ae90b508c2cbc95d3b8d4
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.1"
+  fl_chart:
+    dependency: "direct main"
+    description:
+      name: fl_chart
+      sha256: "00b74ae680df6b1135bdbea00a7d1fc072a9180b7c3f3702e4b19a9943f5ed7d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.66.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -176,14 +240,30 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  frontend_server_client:
+    dependency: transitive
+    description:
+      name: frontend_server_client
+      sha256: f64a0333a82f30b0cca061bc3d143813a486dc086b574bfb233b7c1372427694
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.0.0"
+  glob:
+    dependency: transitive
+    description:
+      name: glob
+      sha256: c3f1ee72c96f8f78935e18aa8cecced9ab132419e8625dc187e1c2408efc20de
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.3"
   go_router:
     dependency: "direct main"
     description:
       name: go_router
-      sha256: f02fd7d2a4dc512fec615529824fdd217fecb3a3d3de68360293a551f21634b3
+      sha256: eb059dfe59f08546e9787f895bd01652076f996bcbf485a8609ef990419ad227
       url: "https://pub.dev"
     source: hosted
-    version: "14.8.1"
+    version: "16.2.1"
   google_fonts:
     dependency: "direct main"
     description:
@@ -208,6 +288,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.5.0"
+  http_multi_server:
+    dependency: transitive
+    description:
+      name: http_multi_server
+      sha256: aa6199f908078bb1c5efb8d8638d4ae191aac11b311132c3ef48ce352fb52ef8
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.2.2"
   http_parser:
     dependency: transitive
     description:
@@ -224,6 +312,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.5.4"
+  io:
+    dependency: transitive
+    description:
+      name: io
+      sha256: dfd5a80599cf0165756e3181807ed3e77daf6dd4137caaad72d0b7931597650b
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.5"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      sha256: "53385261521cc4a0c4658fd0ad07a7d14591cf8fc33abbceae306ddb974888dc"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.7.2"
   json_annotation:
     dependency: transitive
     description:
@@ -312,6 +416,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.16.0"
+  mime:
+    dependency: transitive
+    description:
+      name: mime
+      sha256: "41a20518f0cb1256669420fdba0cd90d21561e560ac240f26ef8322e45bb7ed6"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.0"
   nested:
     dependency: transitive
     description:
@@ -320,6 +432,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.0"
+  node_preamble:
+    dependency: transitive
+    description:
+      name: node_preamble
+      sha256: "6e7eac89047ab8a8d26cf16127b5ed26de65209847630400f9aefd7cd5c730db"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.2"
+  package_config:
+    dependency: transitive
+    description:
+      name: package_config
+      sha256: f096c55ebb7deb7e384101542bfba8c52696c1b56fca2eb62827989ef2353bbc
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.0"
   path:
     dependency: transitive
     description:
@@ -408,6 +536,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.8"
+  pool:
+    dependency: transitive
+    description:
+      name: pool
+      sha256: "20fe868b6314b322ea036ba325e6fc0711a22948856475e2c2b6306e8ab39c2a"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.1"
   posix:
     dependency: transitive
     description:
@@ -424,11 +560,75 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "6.1.5+1"
+  pub_semver:
+    dependency: transitive
+    description:
+      name: pub_semver
+      sha256: "5bfcf68ca79ef689f8990d1160781b4bad40a3bd5e5218ad4076ddb7f4081585"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.0"
+  rational:
+    dependency: "direct main"
+    description:
+      name: rational
+      sha256: cb808fb6f1a839e6fc5f7d8cb3b0a10e1db48b3be102de73938c627f0b636336
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.3"
+  shelf:
+    dependency: transitive
+    description:
+      name: shelf
+      sha256: e7dd780a7ffb623c57850b33f43309312fc863fb6aa3d276a754bb299839ef12
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.2"
+  shelf_packages_handler:
+    dependency: transitive
+    description:
+      name: shelf_packages_handler
+      sha256: "89f967eca29607c933ba9571d838be31d67f53f6e4ee15147d5dc2934fee1b1e"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.2"
+  shelf_static:
+    dependency: transitive
+    description:
+      name: shelf_static
+      sha256: c87c3875f91262785dade62d135760c2c69cb217ac759485334c5857ad89f6e3
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.3"
+  shelf_web_socket:
+    dependency: transitive
+    description:
+      name: shelf_web_socket
+      sha256: "3632775c8e90d6c9712f883e633716432a27758216dfb61bd86a8321c0580925"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.0"
   sky_engine:
     dependency: transitive
     description: flutter
     source: sdk
     version: "0.0.0"
+  source_map_stack_trace:
+    dependency: transitive
+    description:
+      name: source_map_stack_trace
+      sha256: c0713a43e323c3302c2abe2a1cc89aa057a387101ebd280371d6a6c9fa68516b
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.2"
+  source_maps:
+    dependency: transitive
+    description:
+      name: source_maps
+      sha256: "190222579a448b03896e0ca6eca5998fa810fda630c1d65e2f78b3f638f54812"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.10.13"
   source_span:
     dependency: transitive
     description:
@@ -469,6 +669,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.2.2"
+  test:
+    dependency: "direct dev"
+    description:
+      name: test
+      sha256: "65e29d831719be0591f7b3b1a32a3cda258ec98c58c7b25f7b84241bc31215bb"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.26.2"
   test_api:
     dependency: transitive
     description:
@@ -477,6 +685,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.7.6"
+  test_core:
+    dependency: transitive
+    description:
+      name: test_core
+      sha256: "80bf5a02b60af04b09e14f6fe68b921aad119493e26e490deaca5993fef1b05a"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.6.11"
   tuple:
     dependency: transitive
     description:
@@ -605,6 +821,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "15.0.2"
+  watcher:
+    dependency: transitive
+    description:
+      name: watcher
+      sha256: "5bf046f41320ac97a469d506261797f35254fa61c641741ef32dacda98b7d39c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.3"
   web:
     dependency: transitive
     description:
@@ -613,6 +837,30 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.1"
+  web_socket:
+    dependency: transitive
+    description:
+      name: web_socket
+      sha256: "34d64019aa8e36bf9842ac014bb5d2f5586ca73df5e4d9bf5c936975cae6982c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.1"
+  web_socket_channel:
+    dependency: transitive
+    description:
+      name: web_socket_channel
+      sha256: d645757fb0f4773d602444000a8131ff5d48c9e47adfe9772652dd1a4f2d45c8
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.3"
+  webkit_inspection_protocol:
+    dependency: transitive
+    description:
+      name: webkit_inspection_protocol
+      sha256: "87d3f2333bb240704cd3f1c6b5b7acd8a10e7f0bc28c28dcf14e782014f4a572"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.1"
   xdg_directories:
     dependency: transitive
     description:

pubspec.yaml

@@ -16,7 +16,7 @@ publish_to: "none" # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 1.0.0+3
+version: 1.0.0+4
 
 environment:
   sdk: ^3.9.2
@@ -37,8 +37,10 @@ dependencies:
   math_expressions: ^3.1.0
   latext: ^0.5.1
   google_fonts: ^6.3.1
-  go_router: ^14.2.0
-  url_launcher: ^6.3.0
+  go_router: ^16.2.1
+  url_launcher: ^6.3.2
+  rational: ^2.2.3
+  fl_chart: ^0.66.1
 
 dev_dependencies:
   flutter_test:
@@ -52,6 +54,7 @@ dev_dependencies:
   flutter_lints: ^6.0.0
   flutter_native_splash: ^2.4.6
   flutter_launcher_icons: ^0.14.4
+  test: ^1.26.2
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec

test/calculator_test.dart

@@ -0,0 +1,104 @@
+import 'package:simple_math_calc/parser.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('整数', () {
+    test('加法', () {
+      var expr = Parser("2 + 3").parse();
+      expect(expr.evaluate().toString(), "5");
+    });
+
+    test('乘法', () {
+      var expr = Parser("4 * 5").parse();
+      expect(expr.evaluate().toString(), "20");
+    });
+  });
+
+  group('分数', () {
+    test('简单分数', () {
+      var expr = Parser("1/2").parse();
+      expect(expr.evaluate().toString(), "1/2");
+    });
+
+    test('分数加法', () {
+      var expr = Parser("1/2 + 3/4").parse();
+      expect(expr.evaluate().toString().replaceAll(' ', ''), "5/4");
+    });
+
+    test('分数与整数相乘', () {
+      var expr = Parser("2 * 3/4").parse();
+      expect(expr.evaluate().toString(), "3/2");
+    });
+  });
+
+  group('开平方', () {
+    test('完全平方数', () {
+      var expr = Parser("sqrt(9)").parse();
+      expect(expr.evaluate().toString(), "3");
+    });
+
+    test('非完全平方数', () {
+      var expr = Parser("sqrt(8)").parse();
+      expect(expr.simplify().toString().replaceAll(' ', ''), "(2*sqrt(2))");
+    });
+  });
+
+  group('组合表达式', () {
+    test('sqrt + 整数', () {
+      var expr = Parser("2 + sqrt(9)").parse();
+      expect(expr.simplify().toString().replaceAll(' ', ''), "(2+3)");
+    });
+
+    test('分数 + sqrt', () {
+      var expr = Parser("sqrt(8)/4 + 1/2").parse();
+      expect(
+        expr.evaluate().toString().replaceAll(' ', ''),
+        "((sqrt(2)/2)+1/2)",
+      );
+    });
+  });
+
+  group('加减除优先级', () {
+    test('减法', () {
+      var expr = Parser("5 - 2").parse();
+      expect(expr.evaluate().toString(), "3");
+    });
+
+    test('除法', () {
+      var expr = Parser("6 / 3").parse();
+      expect(expr.evaluate().toString(), "2");
+    });
+
+    test('加法和乘法优先级', () {
+      var expr = Parser("1 + 2 * 3").parse();
+      expect(expr.evaluate().toString(), "7");
+    });
+
+    test('加减混合', () {
+      var expr = Parser("10 - 3 + 2").parse();
+      expect(expr.evaluate().toString(), "9");
+    });
+
+    test('括号优先级', () {
+      var expr = Parser("(1 + 2) * 3").parse();
+      expect(expr.evaluate().toString(), "9");
+    });
+  });
+
+  group('三角函数', () {
+    test('cos(0)', () {
+      var expr = Parser("cos(0)").parse();
+      expect(expr.evaluate().toString(), "1.0");
+    });
+
+    test('sin(0)', () {
+      var expr = Parser("sin(0)").parse();
+      expect(expr.evaluate().toString(), "0.0");
+    });
+
+    test('tan(0)', () {
+      var expr = Parser("tan(0)").parse();
+      expect(expr.evaluate().toString(), "0.0");
+    });
+  });
+}

test/core_test.dart

@@ -0,0 +1,62 @@
+import 'package:test/test.dart';
+import 'package:simple_math_calc/calculator.dart';
+import 'package:simple_math_calc/parser.dart';
+
+void main() {
+  group('解析器测试', () {
+    test('简单加法', () {
+      final parser = Parser('2 + 3');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '5');
+    });
+
+    test('乘法和加法优先级', () {
+      final parser = Parser('2 + 3 * 4');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '14');
+    });
+
+    test('括号优先级', () {
+      final parser = Parser('(2 + 3) * 4');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '20');
+    });
+
+    test('除法', () {
+      final parser = Parser('10 / 2');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '5');
+    });
+
+    test('平方根', () {
+      final parser = Parser('sqrt(9)');
+      final expr = parser.parse();
+      final result = expr.evaluate();
+      expect(result.toString(), '3');
+    });
+  });
+
+  group('计算器测试', () {
+    test('分数简化', () {
+      final fraction = FractionExpr(4, 8);
+      final simplified = fraction.simplify();
+      expect(simplified.toString(), '1/2');
+    });
+
+    test('分数加法', () {
+      final expr = AddExpr(FractionExpr(1, 2), FractionExpr(1, 4));
+      final result = expr.evaluate();
+      expect(result.toString(), '3/4');
+    });
+
+    test('分数乘法', () {
+      final expr = MulExpr(FractionExpr(1, 2), FractionExpr(2, 3));
+      final result = expr.evaluate();
+      expect(result.toString(), '1/3');
+    });
+  });
+}

test/solver_test.dart

@@ -0,0 +1,109 @@
+import 'package:flutter/widgets.dart';
+import 'package:test/test.dart';
+import 'package:simple_math_calc/solver.dart';
+
+void main() {
+  group('求解器测试', () {
+    final solver = SolverService();
+
+    test('简单表达式求值', () {
+      final result = solver.solve('2 + 3 * 4');
+      expect(result.finalAnswer, contains('14'));
+    });
+
+    test('简单方程求解', () {
+      final result = solver.solve('2x + 3 = 7');
+      expect(result.finalAnswer, contains('x = 2'));
+    });
+
+    test('二次方程求解', () {
+      final result = solver.solve('x^2 - 5x + 6 = 0');
+      debugPrint(result.finalAnswer);
+      expect(
+        result.finalAnswer.contains('x_1 = 2') &&
+            result.finalAnswer.contains('x_2 = 3'),
+        true,
+      );
+    });
+
+    test('三角函数求值', () {
+      final result = solver.solve('sin(30)');
+      debugPrint(result.finalAnswer);
+      expect(result.finalAnswer.contains(r'\frac{1}{2}'), true);
+    });
+
+    test('带括号的复杂表达式', () {
+      final result = solver.solve('(2 + 3) * 4');
+      expect(result.finalAnswer, contains('20'));
+    });
+
+    test('括号展开的二次方程', () {
+      final result = solver.solve('(x+8)(x+1)=-12');
+      debugPrint('Result for (x+8)(x+1)=-12: ${result.finalAnswer}');
+      // 这个方程应该被识别为一元二次方程，正确解应该是 x = -4 或 x = -5
+      expect(
+        result.steps.any((step) => step.title == '整理方程'),
+        true,
+        reason: '方程应被识别为一元二次方程并进行整理',
+      );
+      expect(
+        (result.finalAnswer.contains('-4') &&
+                result.finalAnswer.contains('-5')) ||
+            result.finalAnswer.contains('x = -4') ||
+            result.finalAnswer.contains('x = -5'),
+        true,
+      );
+    });
+
+    test('二次方程根的简化', () {
+      final result = solver.solve('x^2 - 4x - 5 = 0');
+      debugPrint('Result for x^2 - 4x - 5 = 0: ${result.finalAnswer}');
+      // 这个方程的根应该是 x = (4 ± √(16 + 20))/2 = (4 ± √36)/2 = (4 ± 6)/2
+      // 所以 x1 = (4 + 6)/2 = 5, x2 = (4 - 6)/2 = -1
+      expect(
+        (result.finalAnswer.contains('x_1 = 5') &&
+                result.finalAnswer.contains('x_2 = -1')) ||
+            (result.finalAnswer.contains('x_1 = -1') &&
+                result.finalAnswer.contains('x_2 = 5')),
+        true,
+        reason: '方程 x^2 - 4x - 5 = 0 的根应该被正确简化',
+      );
+    });
+
+    test('二次方程精确度改进', () {
+      final result = solver.solve('x^2 - 2x - 1 = 0');
+      debugPrint('Result for x^2 - 2x - 1 = 0: ${result.finalAnswer}');
+      // 这个方程的根应该是 x = (2 ± √(4 + 4))/2 = (2 ± √8)/2 = (2 ± 2√2)/2 = 1 ± √2
+      // 验证结果包含正确的根格式
+      expect(
+        result.finalAnswer.contains('x_1') &&
+            result.finalAnswer.contains('x_2'),
+        true,
+        reason: '方程应该有两个根',
+      );
+      expect(
+        result.finalAnswer.contains('1 +') ||
+            result.finalAnswer.contains('1 -'),
+        true,
+        reason: '根应该以 1 ± √2 的形式出现',
+      );
+    });
+
+    test('无实数解的二次方程', () {
+      final result = solver.solve('x(55-3x+2)=300');
+      debugPrint('Result for x(55-3x+2)=300: ${result.finalAnswer}');
+      // 这个方程展开后为 -3x² + 57x - 300 = 0，判别式为负数，应该无实数解
+      expect(
+        result.steps.any((step) => step.formula.contains('无实数解')),
+        true,
+        reason: '方程应该被识别为无实数解',
+      );
+      expect(
+        result.finalAnswer.contains('x_1') &&
+            result.finalAnswer.contains('x_2'),
+        true,
+        reason: '应该提供复数根',
+      );
+    });
+  });
+}

test_expand.dart

@@ -0,0 +1,21 @@
+import 'lib/solver.dart';
+
+void main() {
+  final solver = SolverService();
+
+  // Test the problematic case
+  final input = '(x+8)(x+1)=-12';
+  print('Input: $input');
+
+  try {
+    final result = solver.solve(input);
+    print('Result: ${result.finalAnswer}');
+    print('Steps:');
+    for (final step in result.steps) {
+      print('Step ${step.stepNumber}: ${step.title}');
+      print('  Formula: ${step.formula}');
+    }
+  } catch (e) {
+    print('Error: $e');
+  }
+}