使用PySimpleGUI+Pytube时遇AttributeError：'list'对象无'streams'属性

问题描述 #

我是Python纯新手，之前运行无GUI的Python程序都正常。现在尝试做一个带GUI的YouTube下载器，运行时出现错误：AttributeError: 'list' object has no attribute 'streams'，我的代码如下：

import PySimpleGUI as sg
from pytube import YouTube
import os

sg.theme('Reddit')
choices = ("MP3", "MP4")
yt = YouTube

layout = [[sg.Text("Enter URL:"), sg.Input(key='-URL-')],
          [sg.Listbox(choices, size=(8, len(choices)), key='-CHOICES-')],
          [sg.Submit(button_color="green"), sg.Cancel(button_color="red")]]

window = sg.Window("YouTube Downloader", layout)

while True:
    event, values = window.read()
    if event in (sg.WIN_CLOSED, 'Cancel'):
        break
    elif event == 'Submit':
        yt = [values['-URL-']]
        filetype = [values['-CHOICES-']]
if "-URL-" == choices[1]:
    yt = yt.streams.get_highest_resolution()
    datatype = '.mp4'
else:
    yt = yt.streams.get_audio_only()
    datatype = '.mp3'

destination = "C:\\Users\\Maintain\\Desktop\\testfolder"
out_file = yt.download(output_path=destination)
base, ext = os.path.splitext(out_file)
new_file = base + datatype
os.rename(out_file, new_file)

sg.popup(yt.title + "has been successfully downloaded.")

window.close()

错误原因 #

• 错误将yt赋值为列表：yt = [values['-URL-']]这行把yt变成了包含URL的列表，而非pytube.YouTube实例，导致无法调用streams属性
• filetype获取错误：sg.Listbox返回的values['-CHOICES-']本身是列表，额外套[]后变成列表的列表，无法正确判断文件类型
• 判断逻辑完全错误：if "-URL-" == choices[1]:的条件毫无意义，应该判断选中的文件类型
• 代码缩进错误：下载逻辑未放在Submit事件块内，会在窗口关闭后执行，且此时yt可能未正确初始化

修正后的代码 #

import PySimpleGUI as sg
from pytube import YouTube
import os

sg.theme('Reddit')
choices = ("MP3", "MP4")

layout = [[sg.Text("Enter URL:"), sg.Input(key='-URL-')],
          [sg.Listbox(choices, size=(8, len(choices)), key='-CHOICES-')],
          [sg.Submit(button_color="green"), sg.Cancel(button_color="red")]]

window = sg.Window("YouTube Downloader", layout)

while True:
    event, values = window.read()
    if event in (sg.WIN_CLOSED, 'Cancel'):
        break
    elif event == 'Submit':
        # 创建YouTube实例，而非列表
        yt = YouTube(values['-URL-'])
        # 获取选中的文件类型，Listbox返回列表，取第一个选中项
        if not values['-CHOICES-']:
            sg.popup("请选择下载类型！")
            continue
        filetype = values['-CHOICES-'][0]
        
        # 根据选中类型获取对应流
        if filetype == "MP4":
            stream = yt.streams.get_highest_resolution()
            datatype = '.mp4'
        else:
            stream = yt.streams.get_audio_only()
            datatype = '.mp3'
        
        # 下载文件
        destination = "C:\\Users\\Maintain\\Desktop\\testfolder"
        out_file = stream.download(output_path=destination)
        base, ext = os.path.splitext(out_file)
        new_file = base + datatype
        os.rename(out_file, new_file)
        
        # 弹窗提示下载完成
        sg.popup(f"{yt.title} has been successfully downloaded.")

window.close()

修正说明 #

• 删除无用的yt = YouTube代码，在Submit事件中正确创建YouTube实例
• 正确获取Listbox选中的文件类型，增加未选择类型的提示
• 修正判断条件，根据选中的MP3/MP4获取对应流
• 将所有下载逻辑缩进至Submit事件块内，确保点击提交后才执行
• 优化弹窗提示的字符串拼接方式，避免遗漏空格
• 新增流变量stream，避免覆盖yt实例，方便后续获取视频标题

内容的提问来源于stack exchange，提问作者additionalman