Python Tkinter Text Widget with Auto＆Custom Scroll

Question

我编写了一个简单的基于Tkinter的Python应用程序，该应用程序从串行连接中读取文本并将其添加到窗口中，特别是文本窗口。

经过很多调整和一些非常奇怪的例外，这个工程。然后我添加了自动滚动功能：

self.text.insert(END, str(parsed_line)) 
self.text.yview(END) 

这些行在一个线程中运行。从串行连接读取线程块时，将行分割，然后将所有行添加到小部件。

这也适用。然后我想允许用户滚动，这应该禁用自动滚动，直到用户滚动回到底部。

我发现这个 Stop Text widget from scrolling when content is changed 这似乎是相关的。特别是，我试图从DuckAssasin的评论代码：

if self.myWidgetScrollbar.get() == 1.0: 
    self.myWidget.yview(END) 

我也试过.get()[1]这实际上是我想要的元素（底部位置）。然而，这崩溃，但有以下例外：

Traceback (most recent call last): 
    File "transformer-gui.py", line 119, in run 
    pos = self.scrollbar.get()[1] 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 2809, in get 
    return self._getdoubles(self.tk.call(self._w, 'get')) 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 1028, in _getdoubles 
    return tuple(map(getdouble, self.tk.splitlist(string))) 
ValueError: invalid literal for float(): None 

看起来好像tkinter某处返回None然后被解析为一个浮点数。我在某处读过，例如如果请求的位置不可见，文本的索引方法有时会返回无。

希望有人能帮我解决这个问题！

[编辑]

好吧，我已经组建了一个演示脚本，可以重现这个问题我的Win XP的机器上：

import re,sys,time 
from Tkinter import * 
import Tkinter 
import threading 
import traceback 


class ReaderThread(threading.Thread): 
    def __init__(self, text, scrollbar): 
     print "Thread init" 
     threading.Thread.__init__(self) 
     self.text = text 
     self.scrollbar = scrollbar 
     self.running = True 

    def stop(self): 
     print "Stopping thread" 
     running = False 

    def run(self): 
     print "Thread started" 
     time.sleep(5) 
     i = 1 
     try: 
      while(self.running): 
       # emulating delay when reading from serial interface 
       time.sleep(0.05) 
       line = "the quick brown fox jumps over the lazy dog\n" 

       curIndex = "1.0" 
       lowerEdge = 1.0 
       pos = 1.0 

       # get cur position 
       pos = self.scrollbar.get()[1] 

       # Disable scrollbar 
       self.text.configure(yscrollcommand=None, state=NORMAL) 

       # Add to text window 
       self.text.insert(END, str(line)) 
       startIndex = repr(i) + ".0" 
       curIndex = repr(i) + ".end" 

       # Perform colorization 
       if i % 6 == 0: 
        self.text.tag_add("warn", startIndex, curIndex) 
       elif i % 6 == 1: 
        self.text.tag_add("debug", startIndex, curIndex)        
       elif i % 6 == 2: 
        self.text.tag_add("info", startIndex, curIndex)       
       elif i % 6 == 3: 
        self.text.tag_add("error", startIndex, curIndex)        
       elif i % 6 == 4: 
        self.text.tag_add("fatal", startIndex, curIndex)        
       i = i + 1 

       # Enable scrollbar 
       self.text.configure(yscrollcommand=self.scrollbar.set, state=DISABLED) 

       # Auto scroll down to the end if scroll bar was at the bottom before 
       # Otherwise allow customer scrolling       

       if pos == 1.0: 
        self.text.yview(END) 

       #if(lowerEdge == 1.0): 
       # print "is lower edge!" 
       #self.text.see(curIndex) 
       #else: 
       # print "Customer scrolling", lowerEdge 

       # Get current scrollbar position before inserting 
       #(upperEdge, lowerEdge) = self.scrollbar.get() 
       #print upperEdge, lowerEdge 

       #self.text.update_idletasks() 
     except Exception as e: 
      traceback.print_exc(file=sys.stdout) 
      print "Exception in receiver thread, stopping..." 
      pass 
     print "Thread stopped" 


class Transformer: 
    def __init__(self): 
     pass 

    def start(self): 
     """starts to read linewise from self.in_stream and parses the read lines""" 
     count = 1 
     root = Tk() 
     root.title("Tkinter Auto-Scrolling Test") 
     topPane = PanedWindow(root, orient=HORIZONTAL) 
     topPane.pack(side=TOP, fill=X) 
     lowerPane = PanedWindow(root, orient=VERTICAL) 

     scrollbar = Scrollbar(root) 
     scrollbar.pack(side=RIGHT, fill=Y) 
     text = Text(wrap=WORD, yscrollcommand=scrollbar.set) 
     scrollbar.config(command=text.yview) 
     # Color definition for log levels 
     text.tag_config("debug",foreground="gray50") 
     text.tag_config("info",foreground="green") 
     text.tag_config("warn",foreground="orange") 
     text.tag_config("error",foreground="red") 
     text.tag_config("fatal",foreground="#8B008B") 
     # set default color 
     text.config(background="black", foreground="gray"); 
     text.pack(expand=YES, fill=BOTH)   

     lowerPane.add(text) 
     lowerPane.pack(expand=YES, fill=BOTH) 

     t = ReaderThread(text, scrollbar) 
     print "Starting thread" 
     t.start() 

     try: 
      root.mainloop() 
     except Exception as e: 
      print "Exception in window manager: ", e 

     t.stop() 
     t.join() 


if __name__ == "__main__": 
    try: 
     trans = Transformer() 
     trans.start() 
    except Exception as e: 
     print "Error: ", e 
     sys.exit(1)  

我让这个素文字的运行，并开始上下滚动和一段时间后，我得到了很多总是不同的例外，如：

.\source\testtools\device-log-transformer>python tkinter-autoscroll.py 
Thread init 
Starting thread 
Thread started 
Traceback (most recent call last): 
    File "tkinter-autoscroll.py", line 59, in run 
    self.text.configure(yscrollcommand=self.scrollbar.set, state=DISABLED) 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 1202, in configure 
Stopping thread 
    return self._configure('configure', cnf, kw) 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 1193, in _configure 
    self.tk.call(_flatten((self._w, cmd)) + self._options(cnf)) 
TclError: invalid command name ".14762592" 
Exception in receiver thread, stopping... 
Thread stopped 

.\source\testtools\device-log-transformer>python tkinter-autoscroll.py 
Thread init 
Starting thread 
Thread started 
Stopping thread 
Traceback (most recent call last): 
    File "tkinter-autoscroll.py", line 35, in run 
    pos = self.scrollbar.get()[1] 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 2809, in get 
    return self._getdoubles(self.tk.call(self._w, 'get')) 
TclError: invalid command name ".14762512" 
Exception in receiver thread, stopping... 
Thread stopped 

.\source\testtools\device-log-transformer>python tkinter-autoscroll.py 
Thread init 
Starting thread 
Thread started 
Traceback (most recent call last): 
    File "tkinter-autoscroll.py", line 65, in run 
    self.text.yview(END) 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 3156, in yview 
    self.tk.call((self._w, 'yview') + what) 
Stopping threadTclError: invalid command name ".14762592" 

Exception in receiver thread, stopping... 
Thread stopped 

.\source\testtools\device-log-transformer>python tkinter-autoscroll.py 
Thread init 
Starting thread 
Thread started 
Traceback (most recent call last): 
    File "tkinter-autoscroll.py", line 35, in run 
    pos = self.scrollbar.get()[1] 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 2809, in get 
    return self._getdoubles(self.tk.call(self._w, 'get')) 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 1028, in _getdoubles 
    return tuple(map(getdouble, self.tk.splitlist(string))) 
ValueError: invalid literal for float(): None 
Exception in receiver thread, stopping... 
Thread stopped 
Stopping thread 

.\source\testtools\device-log-transformer>python tkinter-autoscroll.py 
Thread init 
Starting thread 
Thread started 
Traceback (most recent call last): 
    File "tkinter-autoscroll.py", line 53, in run 
    self.text.tag_add("error", startIndex, curIndex) 
    File "C:\Python26\lib\lib-tk\Tkinter.py", line 3057, in tag_add 
    (self._w, 'tag', 'add', tagName, index1) + args) 
TclError: bad option "261.0": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, pe 
er, replace, scan, search, see, tag, window, xview, or yview 
Exception in receiver thread, stopping... 
Thread stopped 

我希望这有助于你帮我:)

个

谢谢，

/J

Answer 1

OK，

基于由小白oddy提出宝贵的建议，我能够通过使用Tkinter.generate_event()方法来产生异步事件和队列传递信息重写示例脚本。

每次从流中读取一行（由常量字符串和延迟模拟），我将行追加到队列中（因为不支持将事件传递给事件方法AFAIK），然后创建一个新事件。

事件回调方法从队列中检索消息并将其添加到文本窗口。这是有效的，因为这种方法是从Tkinter主循环调用的，因此它不会干扰其他工作。

下面是脚本：再次

import re,sys,time 
from Tkinter import * 
import Tkinter 
import threading 
import traceback 
import Queue 


class ReaderThread(threading.Thread): 
    def __init__(self, root, queue): 
     print "Thread init" 
     threading.Thread.__init__(self) 
     self.root = root 
     self.running = True 
     self.q = queue 

    def stop(self): 
     print "Stopping thread" 
     running = False 

    def run(self): 
     print "Thread started" 
     time.sleep(5) 

     try: 
      while(self.running): 
       # emulating delay when reading from serial interface 
       time.sleep(0.05) 
       curline = "the quick brown fox jumps over the lazy dog\n" 

       try: 
        self.q.put(curline) 
        self.root.event_generate('<<AppendLine>>', when='tail') 
       # If it failed, the window has been destoyed: over 
       except TclError as e: 
        print e 
        break 

     except Exception as e: 
      traceback.print_exc(file=sys.stdout) 
      print "Exception in receiver thread, stopping..." 
      pass 
     print "Thread stopped" 


class Transformer: 
    def __init__(self): 
     self.q = Queue.Queue() 
     self.lineIndex = 1 
     pass 

    def appendLine(self, event): 
     line = self.q.get_nowait() 

     if line == None: 
      return 

     i = self.lineIndex 
     curIndex = "1.0" 
     lowerEdge = 1.0 
     pos = 1.0 

     # get cur position 
     pos = self.scrollbar.get()[1] 

     # Disable scrollbar 
     self.text.configure(yscrollcommand=None, state=NORMAL) 

     # Add to text window 
     self.text.insert(END, str(line)) 
     startIndex = repr(i) + ".0" 
     curIndex = repr(i) + ".end" 

     # Perform colorization 
     if i % 6 == 0: 
      self.text.tag_add("warn", startIndex, curIndex) 
     elif i % 6 == 1: 
      self.text.tag_add("debug", startIndex, curIndex)        
     elif i % 6 == 2: 
      self.text.tag_add("info", startIndex, curIndex)       
     elif i % 6 == 3: 
      self.text.tag_add("error", startIndex, curIndex)        
     elif i % 6 == 4: 
      self.text.tag_add("fatal", startIndex, curIndex)        
     i = i + 1 

     # Enable scrollbar 
     self.text.configure(yscrollcommand=self.scrollbar.set, state=DISABLED) 

     # Auto scroll down to the end if scroll bar was at the bottom before 
     # Otherwise allow customer scrolling       

     if pos == 1.0: 
      self.text.yview(END) 

     self.lineIndex = i 

    def start(self): 
     """starts to read linewise from self.in_stream and parses the read lines""" 
     count = 1 
     self.root = Tk() 
     self.root.title("Tkinter Auto-Scrolling Test")# 
     self.root.bind('<<AppendLine>>', self.appendLine) 
     self.topPane = PanedWindow(self.root, orient=HORIZONTAL) 
     self.topPane.pack(side=TOP, fill=X) 
     self.lowerPane = PanedWindow(self.root, orient=VERTICAL) 

     self.scrollbar = Scrollbar(self.root) 
     self.scrollbar.pack(side=RIGHT, fill=Y) 
     self.text = Text(wrap=WORD, yscrollcommand=self.scrollbar.set) 
     self.scrollbar.config(command=self.text.yview) 
     # Color definition for log levels 
     self.text.tag_config("debug",foreground="gray50") 
     self.text.tag_config("info",foreground="green") 
     self.text.tag_config("warn",foreground="orange") 
     self.text.tag_config("error",foreground="red") 
     self.text.tag_config("fatal",foreground="#8B008B") 
     # set default color 
     self.text.config(background="black", foreground="gray"); 
     self.text.pack(expand=YES, fill=BOTH)  

     self.lowerPane.add(self.text) 
     self.lowerPane.pack(expand=YES, fill=BOTH) 

     t = ReaderThread(self.root, self.q) 
     print "Starting thread" 
     t.start() 

     try: 
      self.root.mainloop() 
     except Exception as e: 
      print "Exception in window manager: ", e 

     t.stop() 
     t.join() 


if __name__ == "__main__": 
    try: 
     trans = Transformer() 
     trans.start() 
    except Exception as e: 
     print "Error: ", e 
     sys.exit(1)  

感谢大家谁贡献您的帮助！

Answer 2

这很难说究竟发生了什么事情，但你有没有考虑过使用一个队列？

from Tkinter import * 
import time, Queue, thread 

def simulate_input(queue): 
    for i in range(100): 
     info = time.time() 
     queue.put(info) 
     time.sleep(0.5) 

class Demo: 
    def __init__(self, root, dataQueue): 
     self.root = root 
     self.dataQueue = dataQueue 

     self.text = Text(self.root, height=10) 
     self.scroller = Scrollbar(self.root, command=self.text.yview) 
     self.text.config(yscrollcommand=self.scroller.set) 
     self.text.tag_config('newline', background='green') 
     self.scroller.pack(side='right', fill='y') 
     self.text.pack(fill='both', expand=1) 

     self.root.after_idle(self.poll) 

    def poll(self): 
     try: 
      data = self.dataQueue.get_nowait() 
     except Queue.Empty: 
      pass 
     else: 
      self.text.tag_remove('newline', '1.0', 'end') 
      position = self.scroller.get() 
      self.text.insert('end', '%s\n' %(data), 'newline')    
      if (position[1] == 1.0): 
       self.text.see('end') 
     self.root.after(1000, self.poll) 

q = Queue.Queue() 
root = Tk() 
app = Demo(root, q) 

worker = thread.start_new_thread(simulate_input, (q,)) 
root.mainloop() 

Answer 3

关于您的演示脚本。

你正在从非GUI线程做GUI的东西。这往往会造成问题。

看到：http://www.effbot.org/zone/tkinter-threads.htm