trjhtr

I wrote a small program which downloads song or video from the given youtube link.
I used pytube library https://github.com/nficano/pytube and for GUI (Tkinter).

from pytube import YouTube
import tkinter as tk
from tkinter import ttk
from tkinter import filedialog
import re
import threading

"""Program downloads song or video
from youtube page using pytube library
more info about pytube 
can be found here: https://github.com/nficano/pytube
GUI created with tkinter"""



# Main class where user inputs and choose available options
class MainApplication(tk.Frame):

 def __init__(self, master=None, *args, **kwargs):
 tk.Frame.__init__(self, master)
 self.master = master

 self.master.state("zoomed")

 # Window layout
 self.master.grid_rowconfigure(0, weight=2)
 self.master.grid_columnconfigure(0, weight=1)

 # Youtube link label
 self.youtubeLinkLabel = ttk.Label(self.master, text="Please copy the youtube link: ", font=("Agency FB", 30))
 self.youtubeLinkLabel.grid()

 # Youtube entry where user inputs the youtube link
 self.youtubeEntryVar = tk.StringVar()
 self.youtubeEntry = ttk.Entry(self.master, width=50, textvariable=self.youtubeEntryVar)
 self.youtubeEntry.grid(pady=(0,100))

 # Entry error label if user inputs incorrect 
 # link the label will say wrong link
 # checkYoutubeLink function
 self.youtubeEntryError = tk.Label(self.master, text="", font=("Agency FB", 20))
 self.youtubeEntryError.grid(pady=(0,30))

 # Asking where to save file label
 self.youtubeFileLocationLabel = ttk.Label(self.master, text="Please choose folder where to download file: ", font=("Agency FB", 30))
 self.youtubeFileLocationLabel.grid()

 # Button to open directory
 # command = self.openDirectory
 self.youtubeFileLocationEntry = ttk.Button(self.master, text="Directory", command=self.openDirectory)
 self.youtubeFileLocationEntry.grid(pady=(20,40))

 # Entry label if user don`t choose directory
 # openDirectory func
 self.fileLocationLabelError = tk.Label(self.master, text="", font=("Agency FB", 20))
 self.fileLocationLabelError.grid()

 # What to download MP3 or MP4 label
 self.youtubeChooseLabel = ttk.Label(self.master, text="Please choose what to download: ", font=("Agency FB", 30))
 self.youtubeChooseLabel.grid()

 # RadioButton with two choices: MP3 or MP4
 downloadChoices = [("Song MP3", 1), ("Video MP4", 2)]
 self.ChoicesVar = tk.StringVar()
 self.ChoicesVar.set(1)
 for text, mode in downloadChoices:
 self.youtubeChoices = ttk.Radiobutton(self.master, text=text, variable=self.ChoicesVar, value=mode).grid()

 # Download button which at first checks if
 # youtube link is correct then checks if Directory
 # were chosen and if both is correct then start to 
 # download the file
 self.nextButton = ttk.Button(self.master, text="Download", width=10, command=self.checkYoutubeLink)
 self.nextButton.grid(pady=(180,80))

 # This func opens the directory and
 # checks if user chose directory or not
 # if not the proper message is displayed
 # if yes then directory is shown on gui
 def openDirectory(self):

 self.FolderName = filedialog.askdirectory()

 if(len(self.FolderName) > 1):
 self.fileLocationLabelError.config(text=self.FolderName, fg="green")
 return True
 else:
 self.fileLocationLabelError.config(text="Please choose folder!", fg="red")

 # This func checks if youtube link is correct with regex
 # And checks if directory was chosen
 # if both is correct the it proceeds with downloading the file
 def checkYoutubeLink(self):

 matchYoutubeLink = re.match('^https://www.youtube.com/.*', self.youtubeEntryVar.get())

 if(not matchYoutubeLink):
 self.youtubeEntryError.config(text="Wrong youtube link!", fg="red")

 elif(not self.openDirectory):
 self.fileLocationLabelError.config(text="Please choose folder!", fg="red")

 elif(matchYoutubeLink) and self.openDirectory:
 self.downloadWindow()

 # Func hides the MainApplication window and goes to the SecondPage window
 # 3 arguments are passed to the next class window
 def downloadWindow(self):

 self.newWindow = tk.Toplevel(self.master)
 self.master.withdraw()
 self.app = SecondPage(self.newWindow, self.youtubeEntryVar.get(), self.FolderName, self.ChoicesVar.get())



# This class shows downloading process
class SecondPage(tk.Frame):
 def __init__(self, master, youtubeEntry, folderName, ChoicesVar):

 tk.Frame.__init__(self, master)
 self.master = master

 self.master.state("zoomed")

 self.master.grid_rowconfigure(0, weight=0)
 self.master.grid_columnconfigure(0, weight=1)

 self.youtubeEntry = youtubeEntry 
 self.FolderLocation = folderName
 self.ChoicesVar = ChoicesVar


 # describe pytube with yt
 self.yt = YouTube(self.youtubeEntry)

 # Here we are checking what user chose
 # song or video to download
 if(self.ChoicesVar == "1"):
 self.video_type = self.yt.streams.filter(only_audio = True).first()
 self.MaxfileSize = self.video_type.filesize

 elif(self.ChoicesVar == "2"):
 self.video_type = self.yt.streams.first()
 self.MaxfileSize = self.video_type.filesize

 # Loading label
 self.loadingLabel = ttk.Label(self.master, text="Loading...", font=("Agency FB", 30))
 self.loadingLabel.grid(pady=(100,0))

 # loading precent label which must show % donwloaded
 self.loadingPercent = tk.Label(self.master, text="0", fg="green", font=("Agency FB", 30))
 self.loadingPercent.grid(pady=(30,30))

 # indeterminate progress bar
 self.progressbar = ttk.Progressbar(self.master, orient="horizontal", length=500, mode='indeterminate')
 self.progressbar.grid(pady=(50,0))
 self.progressbar.start() 

 # I use threads here to call both functions because otherwise
 # one function downloads the file and only then shows the gui window
 # to solve this issue i used threads
 threading.Thread(target=self.yt.register_on_progress_callback(self.show_progress_bar)).start()

 # call Download file func
 threading.Thread(target=self.DownloadFile).start()

 # This function checks what user chose MP3 or MP4
 # and downloads the file
 def DownloadFile(self):
 if(self.ChoicesVar == "1"):
 self.yt.streams.filter(only_audio=True).first().download(self.FolderLocation)
 elif(self.ChoicesVar == "2"):
 self.yt.streams.first().download(self.FolderLocation)

 # This function show the progress in %
 # when 100% is reached then gui outputs
 # the chosen folder location
 # file title
 # file size in MB
 def show_progress_bar(self, stream=None, chunk=None, file_handle=None, bytes_remaining=None):

 # loadingPercent label configure value %
 percentCount = float("%0.2f"% (100 - (100*(bytes_remaining/self.MaxfileSize))))

 if(percentCount < 100):
 self.loadingPercent.config(text=str(percentCount)+"%")

 else:
 # When 100% is reached then forget loading
 # labels and progress bar
 self.progressbar.stop()

 self.loadingLabel.grid_forget()
 self.loadingPercent.grid_forget()
 self.progressbar.grid_forget()

 # finished label
 self.downloadFinished = ttk.Label(self.master, text="Finished", font=("Agency FB", 30))
 self.downloadFinished.grid(pady=(150,0))

 # Folder location label
 self.downloadLocation = ttk.Label(self.master, text=self.FolderLocation, font=("Agency FB", 30))
 self.downloadLocation.grid(pady=(50,0))

 # Title label
 self.downloadedFileTitle = ttk.Label(self.master, text=self.yt.title, font=("Agency FB", 30))
 self.downloadedFileTitle.grid(pady=(50,0))

 # Label shows MB count 
 MB = float("%0.2f"% (self.MaxfileSize/1000000))
 self.downloadedFileSize = ttk.Label(self.master, text=(str(MB) + "MB"), font=("Agency FB", 30))
 self.downloadedFileSize.grid(pady=(50,0))

 # Exit button
 self.Exit_button = ttk.Button(self.master, text="Exit", command=quit)
 self.Exit_button.grid(pady=(200,0))


if __name__ == "__main__":

 root = tk.Tk()
 root.title("Youtube program")
 app = MainApplication(root)
 root.mainloop()

Questions:

1. In the MainApplication I have 60 lines of various widgets is there any convention to divide widgets to make code more readable? At this moment I am writing another program and there I will have 150-200 lines of various widgets on the main page.


2. When user write something in the ttk.Entry I want to check if input is correct or not and go to the next Frame if correct. I wrote exactly that and it works fine, but perhaps is there are easier solution/convention?

I know that naming convention in this program is incorrect I will change that.
Any other thoughts/opinions is much appreciated, Thanks.