I've been having difficulty with my PySide program for a few days now. I don't think the problem is incredibly difficult because there are answer out there. Problem I have is none of them seem to work for me.
I want to 'listen' to the file objects stdout and stderr and output the contents to QText Edit widget while my PySide program is running. Now, I already realise this question (or something similar) has been asked before on here but like I said, can't get it to work for me for some reason and most other solutions out there are based on the one that I can't get working, so a very frustrating last few days for me. This solution (OutLog), is included in my code snippet below, just in case one of you guys can see a botched implementation on my part.
Things to remember:
1 I'm doing this on Windows 7(duuuh, da, da, duh)
2 I'm using eclipse and running it from inside the IDE(duh, da, da, duh, DUUUUH: It would be really handy if the suggestions worked with either commandline or an IDE)
3 I really just want to duplicate the output of stdout and stderr to the widget while the program runs. For this to happen line-by-line would be a dream but even if it all comes out as a chunk at the end of a loop or something, that would be fab.
4 Oh, and also regarding OutLog, could somebody tell me how, if self.out is set to 'None' in the init, this class can actually work? I mean, self.out is always a NoneType object, right???
Any help would be appreciated, even if it's just pointers to where I could find more information. I've been trying to build my own solution (I'm a bit of a sadist that way) but I've found it hard to find relevant info on how these objects work to do that.
Anyway, whine over. Here's my code:
#!/usr/bin/env python
import sys
import logging
import system_utilities
log = logging.getLogger()
log.setLevel("DEBUG")
log.addHandler(system_utilities.SystemLogger())
import matplotlib
matplotlib.use("Qt4Agg")
matplotlib.rcParams["backend.qt4"] = "PySide"
import subprocess
import plot_widget
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
from PySide import QtCore, QtGui
class MainWindow(QtGui.QMainWindow):
"""This is the main window class and displays the primary UI when launched.
Inherits from QMainWindow.
"""
def __init__(self):
"""Init function.
"""
super(MainWindow, self).__init__()
self.x = None
self.y = None
self.data_plot = None
self.plot_layout = None
self.terminal = None
self.setup_plot()
self.setup_interface()
def setup_plot(self):
"""Member function to setup the graph window in the main UI.
"""
#Create a PlotWidget object
self.data_plot = plot_widget.PlotWidget()
#Create a BoxLayout element to hold PlotWidget
self.plot_layout = QtGui.QVBoxLayout()
self.plot_layout.addWidget(self.data_plot)
def setup_interface(self):
"""Member function to instantiate and build the composite elements of the
UI."""
#Main widget houses layout elements (Layout cannot be placed directly in a QMainWindow).
central_widget = QtGui.QWidget()
test_splitter = QtGui.QSplitter(QtCore.Qt.Vertical)
button_splitter = QtGui.QSplitter(QtCore.Qt.Horizontal)
#UI BoxLayout elements
central_layout = QtGui.QVBoxLayout()
#button_layout = QtGui.QHBoxLayout()
#UI PushButton elements
exit_button = QtGui.QPushButton("Close")
run_button = QtGui.QPushButton("Run...")
#UI Text output
self.editor = QtGui.QTextEdit()
self.editor.setReadOnly(True)
self.terminal = QtGui.QTextBrowser()
self.terminal.setReadOnly(True)
#UI PushButton signals
run_button.clicked.connect(self.run_c_program)
run_button.clicked.connect(self.data_plot.redraw_plot)
exit_button.clicked.connect(QtCore.QCoreApplication.instance().quit)
#Build the UI from composite elements
central_layout.addLayout(self.plot_layout)
central_layout.addWidget(self.editor)
button_splitter.addWidget(run_button)
button_splitter.addWidget(exit_button)
test_splitter.addWidget(button_splitter)
test_splitter.addWidget(self.terminal)
test_splitter.setCollapsible(1, True)
central_layout.addWidget(test_splitter)
central_widget.setLayout(central_layout)
self.setCentralWidget(central_widget)
self.show()
class OutLog:
def __init__(self, edit, out=None, color=None):
"""(edit, out=None, color=None) -> can write stdout, stderr to a
QTextEdit.
edit = QTextEdit
out = alternate stream ( can be the original sys.stdout )
color = alternate color (i.e. color stderr a different color)
"""
self.edit = edit
self.out = None
self.color = color
def write(self, m):
if self.color:
tc = self.edit.textColor()
self.edit.setTextColor(self.color)
self.edit.moveCursor(QtGui.QTextCursor.End)
log.debug("this is m {}".format(m))
self.edit.insertPlainText( m )
if self.color:
self.edit.setTextColor(tc)
if self.out:
self.out.write(m)
def main():
app = QtGui.QApplication(sys.argv)
log.debug("Window starting.")
window = MainWindow()
sys.stdout = OutLog(window.terminal, sys.stdout)
sys.stderr = OutLog(window.terminal, sys.stderr, QtGui.QColor(255,0,0))
window.show()
sys.exit(app.exec_())
log.info("System shutdown.")
if __name__ == '__main__':
main()
"Help me Obi-Wan..."
Thanks in advance guys (and gals :-))
It seems that all you need to do is override sys.stderr and sys.stdout with a wrapper object that emits a signal whenever output is written.
Below is a demo script that should do more or less what you want. Note that the wrapper class does not restore sys.stdout/sys.stderr from sys.__stdout__/sys.__stderr__, because the latter objects may not be same as the ones that were orignally replaced.
PyQt5:
import sys
from PyQt5 import QtWidgets, QtGui, QtCore
class OutputWrapper(QtCore.QObject):
outputWritten = QtCore.pyqtSignal(object, object)
def __init__(self, parent, stdout=True):
super().__init__(parent)
if stdout:
self._stream = sys.stdout
sys.stdout = self
else:
self._stream = sys.stderr
sys.stderr = self
self._stdout = stdout
def write(self, text):
self._stream.write(text)
self.outputWritten.emit(text, self._stdout)
def __getattr__(self, name):
return getattr(self._stream, name)
def __del__(self):
try:
if self._stdout:
sys.stdout = self._stream
else:
sys.stderr = self._stream
except AttributeError:
pass
class Window(QtWidgets.QMainWindow):
def __init__(self):
super().__init__( )
widget = QtWidgets.QWidget(self)
layout = QtWidgets.QVBoxLayout(widget)
self.setCentralWidget(widget)
self.terminal = QtWidgets.QTextBrowser(self)
self._err_color = QtCore.Qt.red
self.button = QtWidgets.QPushButton('Test', self)
self.button.clicked.connect(self.handleButton)
layout.addWidget(self.terminal)
layout.addWidget(self.button)
stdout = OutputWrapper(self, True)
stdout.outputWritten.connect(self.handleOutput)
stderr = OutputWrapper(self, False)
stderr.outputWritten.connect(self.handleOutput)
def handleOutput(self, text, stdout):
color = self.terminal.textColor()
self.terminal.moveCursor(QtGui.QTextCursor.End)
self.terminal.setTextColor(color if stdout else self._err_color)
self.terminal.insertPlainText(text)
self.terminal.setTextColor(color)
def handleButton(self):
if QtCore.QTime.currentTime().second() % 2:
print('Printing to stdout...')
else:
print('Printing to stderr...', file=sys.stderr)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 300, 300, 200)
window.show()
sys.exit(app.exec_())
PyQt4:
import sys
from PyQt4 import QtGui, QtCore
class OutputWrapper(QtCore.QObject):
outputWritten = QtCore.pyqtSignal(object, object)
def __init__(self, parent, stdout=True):
QtCore.QObject.__init__(self, parent)
if stdout:
self._stream = sys.stdout
sys.stdout = self
else:
self._stream = sys.stderr
sys.stderr = self
self._stdout = stdout
def write(self, text):
self._stream.write(text)
self.outputWritten.emit(text, self._stdout)
def __getattr__(self, name):
return getattr(self._stream, name)
def __del__(self):
try:
if self._stdout:
sys.stdout = self._stream
else:
sys.stderr = self._stream
except AttributeError:
pass
class Window(QtGui.QMainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
widget = QtGui.QWidget(self)
layout = QtGui.QVBoxLayout(widget)
self.setCentralWidget(widget)
self.terminal = QtGui.QTextBrowser(self)
self._err_color = QtCore.Qt.red
self.button = QtGui.QPushButton('Test', self)
self.button.clicked.connect(self.handleButton)
layout.addWidget(self.terminal)
layout.addWidget(self.button)
stdout = OutputWrapper(self, True)
stdout.outputWritten.connect(self.handleOutput)
stderr = OutputWrapper(self, False)
stderr.outputWritten.connect(self.handleOutput)
def handleOutput(self, text, stdout):
color = self.terminal.textColor()
self.terminal.moveCursor(QtGui.QTextCursor.End)
self.terminal.setTextColor(color if stdout else self._err_color)
self.terminal.insertPlainText(text)
self.terminal.setTextColor(color)
def handleButton(self):
if QtCore.QTime.currentTime().second() % 2:
print('Printing to stdout...')
else:
sys.stderr.write('Printing to stderr...\n')
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 300, 300, 200)
window.show()
sys.exit(app.exec_())
NB:
Instances of the OutputWrapper should be created as early as possible, so as to ensure that other modules that need sys.stdout/sys.stderr (such as the logging module) use the wrapped versions wherever necessary.
self.out = None is probably a typo and should be self.out = out. That way, you can see anything that printed in the console as well. This is the first step to be sure that the code prints anything at all.
The next thing is that you need to realize which output you're redirecting. A subprocess get its own stdio, so no amount of redirection of the parent's stdout is going to have any effect.
Getting stdio correct with a subprocess isn't trivial. I suggest to start with subprocess.communicate() which gives you all the output as a single string. That's usually good enough.
Related
I'm a little stuck here. I've read lots of stack overflows threads but not getting any further on that topic.
My goal is to have a tinter GUI that at some point launches a function in a new Process and redirects every print in that function to the Guis Text widget. There a Pipes and Queues but im not to familiar with how to use them correctly. I have found a working solution here but that only applies to Python 3. Unfortunately I have to use Python 2.7...
Can anybody help?
my sample code:
from Tkinter import *
import multiprocessing as mp
import time
import sys
class Gui(object):
def __init__(self):
self.a=Tk()
b1=Button(self.a, text="Process 1", command=self.func)
b1.grid(row=0, column=0, pady=10, padx=10, sticky=SE)
self.messages=Text(
self.a, height=2.5, width=30, bg="light cyan", state=NORMAL)
self.messages.grid(row=1, column=0, columnspan=3)
sys.stdout = self.StdoutRedirector(self.messages)
sys.stderr = self.StdoutRedirector(self.messages)
self.a.mainloop()
class StdoutRedirector(object):
def __init__(self, text_widget):
self.output = text_widget
def write(self, string):
self.output.config(state=NORMAL)
self.output.update_idletasks()
self.output.insert('end', string)
self.output.see('end')
self.output.config(state=DISABLED)
def flush(self):
pass
def func(self):
print("test")
proc=mp.Process(target=go)
proc.start()
def go():
for i in range(0,10):
time.sleep((1))
print(i)
if __name__ == "__main__":
Gui()
The issue in your code is that you are changing the content of a tkinter widget outside of the mainloop, which is not possible. One solution I have found is to redirect the stdout and stderr to Queues and periodically read the content of these queues in the mainloop to update the text widget. The periodical reading is done using the method .after(<delay in ms>, <callback>).
from Tkinter import *
import multiprocessing as mp
import time
import sys
class StdoutRedirector(object):
def __init__(self, queue):
self.output = queue
def write(self, string):
self.output.put(string)
def flush(self):
pass
class Gui(object):
def __init__(self):
self.a=Tk()
b1 = Button(self.a, text="Process 1", command=self.func)
b1.grid(row=0, column=0, pady=10, padx=10, sticky=SE)
self.messages=Text(self.a, height=2.5, width=30, bg="light cyan",
state=NORMAL)
self.messages.grid(row=1, column=0, columnspan=3)
self.messages.tag_configure('error', foreground='red')
# queues to get the stdout and stderr
self.stdout = mp.Queue()
self.stderr = mp.Queue()
self.proc = None # process
self.a.mainloop()
def stdout_update(self):
self.messages.configure(state=NORMAL)
while not self.stdout.empty(): # display stdout
self.messages.insert('end', self.stdout.get(False))
while not self.stderr.empty(): # display stderr
self.messages.insert('end', self.stderr.get(False), 'error')
self.messages.configure(state=DISABLED)
if self.proc.is_alive(): # the process is not finished, schedule the next display update
self.a.after(100, self.stdout_update)
def func(self):
self.proc = mp.Process(target=go, args=(self.stdout, self.stderr))
self.proc.start()
self.stdout_update() # launch display update
def go(queue_out, queue_err):
# redirect stdout and stderr to queues
sys.stdout = StdoutRedirector(queue_out)
sys.stderr = StdoutRedirector(queue_err)
for i in range(0, 2):
time.sleep(1)
print(i)
1/0 # to test the stderr
if __name__ == "__main__":
Gui()
In my program i want to use key press event in list view.When i press the enter key then only my selected text will print..Can any one please tell me how to use key press event for list view.I tried with installEventFilter but this method showing non type error.
Given below is my code:
import sys
from PyQt4 import QtCore,QtGui
class List_View(QtGui.QMainWindow):
def __init__(self, parent=None):
super(List_View, self).__init__(parent)
self.listview = QtGui.QListView()
model = QtGui.QStandardItemModel(self.listview)
for i in ['linux', 'windows', 'mac os']:
model.appendRow(QtGui.QStandardItem(i))
self.listview.setModel(model)
self.listview.entered.connect(self.add_items)
widget = QtGui.QWidget()
self.setCentralWidget(widget)
vlay = QtGui.QVBoxLayout(widget)
vlay.addWidget(self.listview)
self.resize(400, 200)
def add_items(self):
pass #here i need to print particular item in list view
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
w = List_View()
w.show()
sys.exit(app.exec_())
I think you have not read the docs of the entered signal or you have not understood it, that signal only triggers when the mouse is on the item but for this you must activate the mouse tracking with self.listview.setMouseTracking(True)
A simple solution is to use a QShortcut:
import sys
from PyQt4 import QtCore,QtGui
class List_View(QtGui.QMainWindow):
def __init__(self, parent=None):
super(List_View, self).__init__(parent)
shorcut = QtGui.QShortcut(
QtGui.QKeySequence(QtCore.Qt.Key_Return),
self
)
shorcut.activated.connect(self.on_enter_pressed)
self.listview = QtGui.QListView()
model = QtGui.QStandardItemModel(self.listview)
for i in ['linux', 'windows', 'mac os']:
model.appendRow(QtGui.QStandardItem(i))
self.listview.setModel(model)
widget = QtGui.QWidget()
self.setCentralWidget(widget)
vlay = QtGui.QVBoxLayout(widget)
vlay.addWidget(self.listview)
self.resize(400, 200)
#QtCore.pyqtSlot()
def on_enter_pressed(self):
print("enter press")
ix = self.listview.selectionModel().currentIndex()
print(ix.data())
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
w = List_View()
w.show()
sys.exit(app.exec_())
Here is my sample code.When i click the ok button i need to change my cursor position to another line edit.How can i change my cursor position in the sample code.Can any one please help me.
Given below is my code:
import sys
from PyQt4 import QtGui
class Example(QtGui.QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
self.vbox = QtGui.QVBoxLayout()
self.le1 = QtGui.QLineEdit()
self.le2 = QtGui.QLineEdit()
self.le3 = QtGui.QLineEdit()
self.ok = QtGui.QPushButton("OK")
self.ok.clicked.connect(self.moving_position)
self.vbox.addWidget(self.le1)
self.vbox.addWidget(self.le2)
self.vbox.addWidget(self.le3)
self.vbox.addWidget(self.ok)
self.setLayout(self.vbox)
self.show()
def moving_position(self):
pass
#how to move cursor to next line edit
def main():
app = QtGui.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == '__main__':
main(
Give this a try: self.le1.setFocus()
I have a class called app.py within that class there's a method called print_raw_records_screen here's the part of the class and the method
app.py
#!/usr/bin/python
# -*- coding: utf-8 -*-
from Tkinter import *
from ttk import *
import os
import mftsession
class Example(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
self.parent = parent
self.filename = ""
self.initUI()
#defining a function that that receives the raw records from the mftsession.py and print it to the screen
#this script will be called by the mftsession.py in
#process_mftfile()
def print_raw_records_screen(self,records):
self.area.delete(1.0, "end")
self.area.insert('1.0',records)
def initUI(self):
self.parent.title("Mtf Analyzer")
#initializing and configuring menubar
menubar = Menu(self.parent)
self.parent.config(menu=menubar)
fileMenu = Menu(menubar)
fileMenu.add_command(label="Open file", command=self.fileOpen)
fileMenu.add_command(label="Exit", command=self.onExit)
menubar.add_cascade(label="File", menu=fileMenu)
#specify grid row and column spaces
self.pack(fill=BOTH, expand=True)
self.columnconfigure(1, weight=1)
self.columnconfigure(3, pad=7)
self.rowconfigure(3, weight=1)
self.rowconfigure(5, pad=7)
lbl = Label(self, text="File Name")
lbl.grid(row=1, column=0, sticky=W, pady=4, padx=5)
self.filename_area = Entry(self)
self.filename_area.grid(row=1, column=1, columnspan=5, padx=5, sticky=E+W+S+N)
analize_button = Button(self, text="Analize", command=self.processFile)
analize_button.grid(row=1, column=6, padx=5)
self.area = Text(self)
self.area.grid(row=2, column=1, columnspan=2, rowspan=4,
padx=5, sticky=E+W+S+N)
#configure the raw output view
def onExit(self):
self.quit()
#this function selects and opens the file to analize
def fileOpen(self):
from tkFileDialog import askopenfilename
Tk().withdraw()
self.filename = askopenfilename()
#populate the filename field
self.set( self.filename)
#do the processing of the file obtained. Populate the file NAME entry or
#send the filename to the analyzeMFT.py
def processFile(self):
arguments = "analyzeMFT.py -f "+self.filename+" -d --bodyfull -l -o "+self.filename+".csv"
os.system(arguments)
mftsession.MftSession.process_mft_file(self)
#get and set methods for the entry field
def get(self):
return self.filename_area.get()
def set(self, value):
self.filename_area.delete(0, END)
self.filename_area.insert(0,value)
def main():
root = Tk()
root.geometry("450x350+500+500")
app = Example(root)
root.mainloop()
if __name__ == '__main__':
main()
This method is called by another external script like this
mftsession.py
import csv
import json
import os
import sys
from optparse import OptionParser
import mft
import app
from Tkinter import *
from ttk import *
class MftSession:
"""Class to describe an entire MFT processing session"""
#staticmethod
def fmt_excel(date_str):
return '="{}"'.format(date_str)
#staticmethod
def fmt_norm(date_str):
return date_str
def __init__(self):
self.mft = {}
self.fullmft = {}
self.folders = {}
self.debug = False
self.mftsize = 0
def process_mft_file(self):
root = Tk()
appi = app.Example(root)
self.sizecheck()
self.build_filepaths()
# reset the file reading
self.num_records = 0
self.file_mft.seek(0)
raw_record = self.file_mft.read(1024)
if self.options.output is not None:
self.file_csv.writerow(mft.mft_to_csv(None, True, self.options))
while raw_record != "":
record = mft.parse_record(raw_record, self.options)
if self.options.debug:
print record
appi.print_raw_records_screen(raw_record ) #THIS FUNCTION WHILE INVOKED THIS WAY IS NOT WORKING
..........
The script analyzeMFT.py called by the app.py through the subrouting
#!/usr/bin/python
import sys
from os import path
def main():
session = mftsession.MftSession()
session.mft_options()
session.open_files()
session.process_mft_file()
if __name__ == '__main__':
if __package__ is None:
sys.path.append( path.dirname( path.dirname( path.abspath(__file__) ) ) )
import mftsession
main()
else:
import mftsession
main()
When called this way it prints nothing to the window, but when i invoke it for testing within its own class it prints the test
def print_raw_records_screen(self,records):
self.area.delete(1.0, "end")
self.area.insert('1.0', records)
and invoke like print_raw_records_screen("any test"): in the app.py
An image can tell alot. and summarize
What am i doing wrong? I sense it's the instantiation am doing wrong. I need diretions please
From what I can see here you have a few issues causing problems.
you are importing app.py on mftsession.py instead importing mftsession.py on app.py.
You are trying to use appi.print_raw_records_screen(raw_record) on a completely different instance of the Example() class with appi = app.Example(root) remove that part all together.
It is bad practice to importing inside a function. Import at the start of each py file.
There is so many things going on in your code I had to create a Minimal, Complete, and Verifiable example example of my own to illustrate the relation between files.
Here is a simple example of how the 2 files can interact and the way I think you are trying to do things.
Here I have created a main file called app.py:
from Tkinter import *
# You might need to import the py file with the package name as well.
# Change the package name to the package your python files are located in.
import PACKAGE_NAME.file_b
class Example(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
self.parent = parent
self.filename = ""
analize_button = Button(self.parent, text="Analize", command=self.processFile)
analize_button.pack()
self.area = Text(self.parent, height = 2, width = 40)
self.area.pack()
def print_raw_records_screen(self,records):
self.area.delete(1.0, "end")
self.area.insert('1.0',records)
def processFile(self):
PACKAGE_NAME.file_b.process_mft_file(self)
if __name__ == "__main__":
root = Tk()
app = Example(root)
root.mainloop()
Here I have created a file called file_b.py
from Tkinter import *
def process_mft_file(self):
record = "Some values assigned to a variable"
self.print_raw_records_screen(record)
The results look something like this:
Below is screenshot of the error. Why does it happen?
This is probably what you are trying to achieve. Although when posting to StackOverflow you should cut and paste your code into the question and not put it in a link, especially a link that is an image.
Few people will make the effort to help, if you make it difficult for them to do so.
import wx
class MyApp(wx.App):
def OnInit(self):
self.frame = MyFrame()
self.SetTopWindow(self.frame)
return True
class MyFrame(wx.Frame):
def __init__(self):
wx.Frame.__init__(self,None, title="Window", pos = (100,150), size =(250,200))
menu = wx.Menu()
menu.Append(1,'&About')
menu.AppendSeparator()
menu.Append(2,'E&xit')
menuBar = wx.MenuBar()
menuBar.Append(menu,'&File')
self.Bind(wx.EVT_MENU, self.OnAbout, id=1)
self.Bind(wx.EVT_MENU, self.OnExit, id=2)
self.SetMenuBar(menuBar)
self.Layout()
self.Show()
def OnExit(self, evt):
self.Destroy()
def OnAbout(self, evt):
print("This is MyFrame")
if __name__ == "__main__":
app = MyApp()
app.MainLoop()
I can't figure out how you even ran that code because your if __name__ == '__main__' and you main method are indented inside your myFrame class. Try out-indenting it I mean your end of code should be like:
def main():
app = myApp()
app.MainLoop()
if __name__ == '__main__':
main()
also, your naming convention is not pythonic.
Python recommends UpperCamelCase for class names, CAPITALIZED_WITH_UNDERSCORES for constants, and lowercase_separated_by_underscores for other names.