如何在Tkinter中更新已有Label的背景色等属性而非新建组件

问题原因 #

• 每次调用display()方法都会重复创建新的Label组件叠加在原有位置，不会复用旧组件
• 创建Label时直接链式调用.grid()方法，由于grid()返回值为None，你无法通过变量获取到已创建的Label实例，自然无法修改原有组件属性

修改方案 #

我们新增一个字典存储所有已创建的Label实例，首次渲染时创建组件并存入字典，后续更新时直接从字典中取出对应实例修改属性即可，不需要重新调用display()新建组件。

完整修改后代码 #

from tkinter import *

class Information():
    def __init__(self, master):
        self.master = master
        self.load_dict_label()
        # 新增字典存储已创建的Label实例，键和配置字典的键保持一致
        self.label_dict = {}
        self.display()

    def display(self):
        for key in self.location_and_condition_label:
            cfg = self.location_and_condition_label[key]
            if key not in self.label_dict:
                # 首次调用时创建Label，拆分创建和grid调用，保存Label实例
                lb = Label(self.master, font=("Courier", 14), text=cfg["text"], bg=cfg["color"])
                lb.grid(row=cfg["row"], column=cfg["column"], padx=5, pady=5)
                self.label_dict[key] = lb
            else:
                # 已存在的组件直接更新属性，不会新建
                self.label_dict[key].config(text=cfg["text"], bg=cfg["color"])

    def load_dict_label(self):
        color = "red"
        self.location_and_condition_label = {
            "0000": {"column": 0, "row": 0, "text": "5:00", "color": color},
            "0001": {"column": 1, "row": 0, "text": "Getting up", "color": color},
            "0002": {"column": 2, "row": 0, "text": "Wash face", "color": color},
            "0003": {"column": 3, "row": 0, "text": "Get dress", "color": color},
            "0004": {"column": 0, "row": 1, "text": "6:00", "color": color},
            "0005": {"column": 1, "row": 1, "text": "Drink coffee", "color": color},
            "0006": {"column": 2, "row": 1, "text": "Read  newspaper", "color": color},
            "0007": {"column": 0, "row": 2, "text": "7:00", "color": color},
            "0008": {"column": 1, "row": 2, "text": "Turn on tv", "color": color},
            "0009": {"column": 2, "row": 2, "text": "Drink coffee", "color": color},
            "0010": {"column": 3, "row": 2, "text": "Wake the child", "color": color},
            "0011": {"column": 4, "row": 2, "text": "Organize the\n child", "color": color},
            "0012": {"column": 5, "row": 2, "text": "Make us \nbreakfast", "color": color},
            "0013": {"column": 0, "row": 3, "text": "8:00", "color": color},
            "0014": {"column": 1, "row": 3, "text": "To go \nto work", "color": color},
            "0015": {"column": 2, "row": 3, "text": "Say hello to\neveryone", "color": color},
            "0016": {"column": 0, "row": 4, "text": "9:00", "color": color},
            "0017": {"column": 1, "row": 4, "text": "Make a morning\ncall", "color": color},
            "0018": {"column": 2, "row": 4, "text": "Start working", "color": color},
            "0019": {"column": 3, "row": 4, "text": "Drink coffee", "color": color}
        }

    def update_label(self):
        # 更新配置字典
        self.location_and_condition_label["0010"]["color"] = "green"
        # 直接修改已有Label的背景色，不需要新建组件
        self.label_dict["0010"].config(bg="green")
        # 如果有批量修改多个Label的需求，也可以直接调用self.display()，不会重复创建组件

class MainPanel():
    def __init__(self, master):
        self._master = master
        self._master.configure(background="#929591")
        self._nformation = Information(self._master)
        self.running = True

    def run(self):
        if self.running == True:
            self._nformation.update_label()
            # 修改一次后把running设为False，避免重复触发更新
            self.running = False
        # 优化回调引用，避免依赖全局app变量
        self._master.after(5000, self.run)

if __name__ == "__main__":
    root = Tk()
    app = MainPanel(root)
    root.after(5000, app.run)
    root.mainloop()

内容的提问来源于stack exchange，提问作者Yovel