from tkinter import *from tkinter.ttk import *import timeimport threadingimport requestsfrom bs4 import BeautifulSoupurl3 = 'http://stackoverflow.com/questions/31241112/blocking-tkinter-interface-until-thread-finishes-its-task'class Interface:    def __init__(self, master):        self.mutex = threading.Lock()        self.m_list = []        self.master = master        self.browse_button= Button (master, text="Browse", command=self.browser)        self.browse_button.pack()        # Create an indeterminate progressbar here but don't pack it.        # Change the maximum to change speed. Smaller == faster.        self.progressbar = Progressbar(mode="indeterminate", maximum=20)    def browser (self):        self.start = time.time()        # set up thread to do work in        self.thread = threading.Thread(target=self.read_file, args=("filename",))        # disable the button        self.browse_button.config(state="disabled")        # show the progress bar        self.progressbar.pack()        # change the cursor        self.master.config(cursor="wait")        # force Tk to update        self.master.update()        # start the thread and progress bar        self.thread.start()        self.progressbar.start()        # check in 50 milliseconds if the thread has finished        self.master.after(50, self.check_completed)    def check_completed(self):        if self.thread.is_alive():            # if the thread is still alive check again in 50 milliseconds            self.master.after(50, self.check_completed)        else:            # if thread has finished stop and reset everything            self.progressbar.stop()            self.progressbar.pack_forget()            self.browse_button.config(state="enabled")            self.master.config(cursor="")            self.master.update()            # Call method to do rest of work, like displaying the info.            self.display_file()    def read_file (self, filename):        # time.sleep(7)  # actually do the read here        self.mutex.acquire()        try:            resp = requests.get(url3)            soup = BeautifulSoup(resp.content, 'html.parser')            for link in soup.select('a'):                self.m_list.append(link.get('href'))        finally:            self.mutex.release()    def display_file(self):        new_list = []        for i in self.m_list:            # print type(i) # unicode            new_list.append(str(i).strip('\n'))        self.cp(new_list)    def cp(self, new_list):        tp = Toplevel(self.master)        text = Text(tp)        text.pack()        text.insert(1.0, '\n'.join(new_list))        print time.time() - self.startwindow = Tk()starter = Interface(window)window.mainloop()