23.1 项目目标

在第22章的记账本基础上，新增以下功能：

1. 收支饼图：显示收入与支出的比例
2. 收支趋势折线图：按日期统计每日收支变化
3. 按钮操作：点击按钮即可弹出图表窗口

23.2 需要的库

pip install matplotlib

Tkinter + matplotlib 结合时，需要使用 FigureCanvasTkAgg 进行嵌入。

23.3 核心代码实现

下面是在第22章 BudgetApp 基础上 新增图表功能 的完整代码：

import tkinter as tk
from tkinter import ttk, messagebox
import sqlite3
from datetime import datetime
import matplotlib.pyplot as plt
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

class BudgetApp:
    def __init__(self, root):
        self.root = root
        self.root.title("记账本（带图表）")
        self.root.geometry("750x550")

        # 连接数据库
        self.conn = sqlite3.connect("budget.db")
        self.cursor = self.conn.cursor()
        self.create_table()

        # 输入区
        frame_input = tk.Frame(self.root)
        frame_input.pack(pady=10)

        tk.Label(frame_input, text="日期(YYYY-MM-DD):").grid(row=0, column=0, padx=5)
        self.entry_date = tk.Entry(frame_input)
        self.entry_date.grid(row=0, column=1, padx=5)
        self.entry_date.insert(0, datetime.now().strftime("%Y-%m-%d"))

        tk.Label(frame_input, text="类别:").grid(row=0, column=2, padx=5)
        self.combo_type = ttk.Combobox(frame_input, values=["收入", "支出"], width=8)
        self.combo_type.grid(row=0, column=3, padx=5)
        self.combo_type.current(0)

        tk.Label(frame_input, text="金额:").grid(row=0, column=4, padx=5)
        self.entry_amount = tk.Entry(frame_input, width=10)
        self.entry_amount.grid(row=0, column=5, padx=5)

        tk.Label(frame_input, text="备注:").grid(row=0, column=6, padx=5)
        self.entry_note = tk.Entry(frame_input, width=15)
        self.entry_note.grid(row=0, column=7, padx=5)

        tk.Button(frame_input, text="添加记录", command=self.add_record).grid(row=0, column=8, padx=10)

        # 表格区
        self.tree = ttk.Treeview(self.root, columns=("id", "date", "type", "amount", "note"), show="headings")
        self.tree.heading("id", text="ID")
        self.tree.heading("date", text="日期")
        self.tree.heading("type", text="类别")
        self.tree.heading("amount", text="金额")
        self.tree.heading("note", text="备注")

        self.tree.column("id", width=50, anchor="center")
        self.tree.column("date", width=100, anchor="center")
        self.tree.column("type", width=80, anchor="center")
        self.tree.column("amount", width=80, anchor="center")
        self.tree.column("note", width=200, anchor="w")

        self.tree.pack(fill=tk.BOTH, expand=True, padx=10, pady=10)

        # 操作按钮
        frame_btn = tk.Frame(self.root)
        frame_btn.pack(pady=5)

        tk.Button(frame_btn, text="删除记录", command=self.delete_record).pack(side=tk.LEFT, padx=10)
        tk.Button(frame_btn, text="统计收支", command=self.show_summary).pack(side=tk.LEFT, padx=10)
        tk.Button(frame_btn, text="收支饼图", command=self.show_pie_chart).pack(side=tk.LEFT, padx=10)
        tk.Button(frame_btn, text="收支趋势图", command=self.show_line_chart).pack(side=tk.LEFT, padx=10)

        # 初始加载数据
        self.load_records()

    def create_table(self):
        self.cursor.execute("""
        CREATE TABLE IF NOT EXISTS records (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            date TEXT,
            type TEXT,
            amount REAL,
            note TEXT
        )
        """)
        self.conn.commit()

    def add_record(self):
        date = self.entry_date.get()
        type_ = self.combo_type.get()
        try:
            amount = float(self.entry_amount.get())
        except ValueError:
            messagebox.showerror("错误", "金额必须是数字")
            return
        note = self.entry_note.get()

        self.cursor.execute("INSERT INTO records (date, type, amount, note) VALUES (?, ?, ?, ?)",
                            (date, type_, amount, note))
        self.conn.commit()
        self.load_records()

        self.entry_amount.delete(0, tk.END)
        self.entry_note.delete(0, tk.END)

    def load_records(self):
        for row in self.tree.get_children():
            self.tree.delete(row)

        self.cursor.execute("SELECT * FROM records ORDER BY date DESC")
        for row in self.cursor.fetchall():
            self.tree.insert("", tk.END, values=row)

    def delete_record(self):
        selected = self.tree.selection()
        if not selected:
            messagebox.showwarning("提示", "请选择要删除的记录")
            return

        record_id = self.tree.item(selected[0])["values"][0]
        self.cursor.execute("DELETE FROM records WHERE id=?", (record_id,))
        self.conn.commit()
        self.load_records()

    def show_summary(self):
        self.cursor.execute("SELECT type, SUM(amount) FROM records GROUP BY type")
        result = self.cursor.fetchall()

        income = sum(r[1] for r in result if r[0] == "收入")
        expense = sum(r[1] for r in result if r[0] == "支出")

        messagebox.showinfo("统计结果", f"总收入: {income} 元\n总支出: {expense} 元\n结余: {income - expense} 元")

    def show_pie_chart(self):
        self.cursor.execute("SELECT type, SUM(amount) FROM records GROUP BY type")
        result = self.cursor.fetchall()

        if not result:
            messagebox.showwarning("提示", "没有数据可显示")
            return

        labels = [r[0] for r in result]
        amounts = [r[1] for r in result]

        fig, ax = plt.subplots()
        ax.pie(amounts, labels=labels, autopct="%1.1f%%", startangle=90)
        ax.set_title("收支比例")

        # 在新窗口中嵌入图表
        win = tk.Toplevel(self.root)
        win.title("收支饼图")
        canvas = FigureCanvasTkAgg(fig, master=win)
        canvas.draw()
        canvas.get_tk_widget().pack(fill=tk.BOTH, expand=True)

    def show_line_chart(self):
        self.cursor.execute("SELECT date, type, SUM(amount) FROM records GROUP BY date, type ORDER BY date")
        result = self.cursor.fetchall()

        if not result:
            messagebox.showwarning("提示", "没有数据可显示")
            return

        dates = sorted(set(r[0] for r in result))
        income_data = []
        expense_data = []

        for d in dates:
            income = sum(r[2] for r in result if r[0] == d and r[1] == "收入")
            expense = sum(r[2] for r in result if r[0] == d and r[1] == "支出")
            income_data.append(income)
            expense_data.append(expense)

        fig, ax = plt.subplots()
        ax.plot(dates, income_data, marker="o", label="收入")
        ax.plot(dates, expense_data, marker="o", label="支出")
        ax.set_title("收支趋势图")
        ax.set_xlabel("日期")
        ax.set_ylabel("金额")
        ax.legend()
        plt.xticks(rotation=45)

        win = tk.Toplevel(self.root)
        win.title("收支趋势图")
        canvas = FigureCanvasTkAgg(fig, master=win)
        canvas.draw()
        canvas.get_tk_widget().pack(fill=tk.BOTH, expand=True)

    def __del__(self):
        self.conn.close()

if __name__ == "__main__":
    root = tk.Tk()
    app = BudgetApp(root)
    root.mainloop()

23.4 功能演示

1. 收支饼图：显示收入和支出的占比。
2. 收支趋势图：按日期统计每天的收入与支出，折线显示变化趋势。
3. 图表在 新窗口 中显示，不影响主界面操作。

23.5 可扩展功能

• 添加 月份筛选，只显示某月的图表
• 使用 条形图 显示各类别支出占比
• 导出图表为 PNG / PDF

23.6 小结

本章我们让记账本应用更直观：

• 通过 matplotlib + Tkinter 实现了收支饼图和趋势折线图
• 学会了在 Tkinter 界面中嵌入 matplotlib 图表
• 为应用增加了数据可视化功能，使财务数据一目了然