Tkinter窗口甚至不响应线程

Question

I'm building a simple GUI with TKinter in Python. I have a browse button that browses files on a computer and open the selected file. When the file is selected a function called to open the file and start reading it. However, after I click the button, the window doesn't respond anymore. When I searched I found that this is because TKinter is single threaded, and the main gui thread may get stuck with some tasks, but even after I've used some simple threading the window still freezes.

Here is a sample code of what I'm doing,

   import threading


from Tkinter import *
from PyQt4 import *
from tkFileDialog import askopenfilename
import numpy as np
import xlrd

global columnList

def open_file (file_name):
    #fileName=input ("Enter file name (example.dat)")
    #colCount= input ("Enter number of columns in the file")

    try:
        workbook = xlrd.open_workbook(file_name)
        sheet=workbook.sheet_by_index(0)
        columns = []
        for i in range (0,sheet.ncols-1):
           columns.append(np.array (sheet.col_values(i,1))) # make a list, each index has a numpy array that represnts a column.
           if (i!=0):
               columns[i]= columns[i].astype(np.float)
        #Preprocessing depth:
        m= columns [0]
        for i in range (m.shape[0]):
            m[i]= m[i]*2 +1

        m=m.astype(np.int)
        columns[0]=m

        print( sheet.row_values(0,sheet.ncols) )
        # removing nans:
        index=input("enter the column index to interpolate: ")
        m= columns [index]
        for i in range (m.shape[0]-1, -1, -1):
            if (np.isnan(m[i])):
                m=np.delete(m,i)
                columns[0]=np.delete(columns[0],i)
                columns [index]= np.delete(columns[index],i)

    except IOError:
        print ("The specified file was not found")

    return columns [0], columns [index]


class Interface:
    def __init__(self, master):
        #frame= Frame (master)
        #frame.grid (sticky=Y)

        self.title= Label(master,text="Kriging Missing data Imputation", fg="blue", font=("Helvetica", 18))
        self.select_file= Label (master, text="Select the file that contains the data (must be an excel file): ", font=("Helvetica", 12))


        self.title.grid (row=1, column=5, columnspan= 4, pady= (20,0))
        self.select_file.grid (row=3, column=1, sticky=W, pady=(20,0), padx=(5,2))
        self.browse_button= Button (master, text="Browse", command=self.browser, font=("Helvetica", 12), width=12)
        self.browse_button.grid (row=3, column=3, pady=(20,0))

        self.varColumn= StringVar(master)
        self.varColumn.set("depth")
        self.columnLabel= Label(master,text="Select a column to process", font=("Helvetica", 12))

        self.columnList= OptionMenu (master, self.varColumn,"nan", "?", "*")

        self.columnLabel.grid (row=5, column=1, pady=(20,0), sticky=W, padx=(5,0))
        self.columnList.grid(row=5, column= 3, pady= (20,0))


        self.missing_label= Label(master, text="Select missing data indicator: ", font=("Helvetica", 12))
        self.var = StringVar (master)
        self.var.set("nan")
        self.menu= OptionMenu (master, self.var,"nan", "?", "*")

        self.missing_label.grid (row=7, column=1, padx=(5,2), pady= (20,0), sticky=W)
        self.menu.grid(row=7, column=3, pady= (20,0))

        self.extrapolate= Label (master, text="Select a range for extrapolation (max=800): ", font=("Helvetica", 12))
        self.max_extra= Entry (master)

        self.extrapolate.grid (row=9, column=1, padx=(5,2), pady= (20,0),  sticky=W)
        self.max_extra.grid (row=9, column=3, pady=(20,0))

        self.a_label= Label (master, text="enter the value of a (range): ", font=("Helvetica", 12))
        self.a_value= Entry (master)

        self.a_label.grid (row=11, column=1, padx=(5,2), pady=(20,0),  sticky=W)
        self.a_value.grid (row=11, column=3,  pady=(20,0))


        self.start_button= Button (master, text="Start", font=("Helvetica", 12), width=12)
        self.pause_button= Button (master, text= "Pause", font=("Helvetica", 12),width=12)
        self.stop_button= Button (master, text="stop", font=("Helvetica", 12),width=12)

        self.start_button.grid (row=13, column=1, pady=(30,0) )
        self.pause_button.grid (row=13, column=2, pady=(30,0))
        self.stop_button.grid (row=13, column=3, pady=(30,0))



    def browser (self):
        filename = askopenfilename()
        x,v= threading.Thread (target=open_file(filename))
        #open_file(filename)
        # we must then send the file name to the function that  reads it somehow.

window= Tk () #main window.
starter= Interface (window)


window.mainloop() #keep the window open until the user decides to close it.

I've read that Tkinter is not thread safe, and I maybe using some threading in some other functions, so how can I solve the problem of freezing with using threading? Or, shall I use another GUI builder like PyQt4?

Any help is appreciated.

Thanks.

Answer 1

You don't use a thread. You are calling open_file and try to start with its return-value a new thread. You have to use the function as an argument, and not call it:

th = threading.Thread(target=open_file, args=(filename,))
th.start()

The next point is, that threads have no return value. When the thread finished, your browser -function has finished long before. So you cannot get the return values x and v . If you want to communicate between threads and GUI you have to use queues and a separate event loop with, which checks the queue and calls itself again with after .

Even Qt is not thread-safe in the way, that some thread can change the GUI. But it has the signal-slot-concept, which replaces queues for communication in a much more convenient way.