PySimpleGUI Listbox动态更新时滚动条位置保持策略

import queue
from threading import Thread
from time import sleep

import PySimpleGUI as sg

numbers_queue = queue.Queue()

# 后台线程函数：持续生成数字并放入队列
def add_number_to_list(numbers_queue):
    list_nums = []
    for i in range(0, 20):
        sleep(0.5) # 模拟耗时操作
        list_nums.append(i)
        numbers_queue.put(list_nums) # 将当前列表状态放入队列

# 定义窗口布局
layout = [
    [sg.Text("PySimpleGUI Listbox 滚动条示例")],
    [sg.Button("开始生成数据", key="Start")],
    [sg.Listbox(values=[], enable_events=True, size=(40, 10), key="-NUMBERS-")]
]

window = sg.Window(title="Listbox 滚动条测试", layout=layout, margins=(50, 50))

# 事件循环
while True:
    event, values = window.read(timeout=100) # 短暂超时，以便处理队列数据

    if event == sg.WIN_CLOSED:
        break
    if event == "Start":
        # 启动后台线程
        numbers_thread = Thread(target=add_number_to_list, args=(numbers_queue,), daemon=True)
        numbers_thread.start()

    # 从队列中获取最新数据并更新Listbox
    try:
        list_of_numbers = numbers_queue.get_nowait()
    except queue.Empty:
        list_of_numbers = [] # 队列为空时，保持当前列表不变

    if list_of_numbers:
        # 每次更新时，滚动条都会跳回顶部
        window["-NUMBERS-"].update(list_of_numbers)

window.close()

if list_of_numbers:
    # 直接将列表长度作为 scroll_to_index 的值
    # PySimpleGUI 会智能地将滚动条定位到显示最后一个元素的位置
    window["-NUMBERS-"].update(list_of_numbers, scroll_to_index=len(list_of_numbers))

import queue
from threading import Thread
from time import sleep

import PySimpleGUI as sg

numbers_queue = queue.Queue()

def add_number_to_list(numbers_queue):
    """后台线程函数：持续生成数字并放入队列"""
    list_nums = []
    for i in range(0, 50): # 生成更多数据以更好地观察滚动效果
        sleep(0.2) # 缩短延迟，加快数据生成速度
        list_nums.append(f"Item {i:03d}") # 格式化字符串，更易读
        numbers_queue.put(list_nums) # 将当前列表状态放入队列
    return

# 定义窗口布局
layout = [
    [sg.Text("PySimpleGUI Listbox 动态滚动示例", font=('Helvetica', 14))],
    [sg.Button("开始生成数据", key="Start", size=(15, 1))],
    [sg.Listbox(values=[], enable_events=True, size=(40, 15), key="-NUMBERS-", font=('Consolas', 10))] # 调整大小和字体
]

window = sg.Window(title="Listbox 滚动条优化", layout=layout, margins=(50, 50))

# 事件循环
while True:
    event, values = window.read(timeout=100) # 短暂超时，以便处理队列数据

    if event == sg.WIN_CLOSED:
        break
    if event == "Start":
        # 确保只启动一个线程，避免重复生成数据
        # 检查是否有名为 "numbers_generator" 的线程正在运行
        if not any(t.is_alive() and t.name == "numbers_generator" for t in Thread.__subclasses__()):
            numbers_thread = Thread(target=add_number_to_list, args=(numbers_queue,), daemon=True, name="numbers_generator")
            numbers_thread.start()

    # 优化：仅当队列非空时才尝试获取数据并更新Listbox
    if not numbers_queue.empty():
        list_of_numbers = numbers_queue.get_nowait()
        if list_of_numbers: # 确保列表不为空，防止空列表更新导致显示问题
            # 计算最后一个元素的索引，并更新Listbox，同时保持滚动条位置
            # 使用 len(list_of_numbers) 作为 scroll_to_index 更为通用和简洁
            window["-NUMBERS-"].update(list_of_numbers, scroll_to_index=len(list_of_numbers))

window.close()