2017-01-25 16 views
2

Я сейчас нахожусь this учебник по потоковому в PyQt (код от here). Как было написано в PyQt4 (и Python2), я адаптировал код для работы с PyQt5 и Python3.PyQt5: объект не имеет атрибута 'connect'

Вот файл графического интерфейса (newdesign.py):

# -*- coding: utf-8 -*- 

# Form implementation generated from reading ui file 'threading_design.ui' 
# 
# Created by: PyQt5 UI code generator 5.6 
# 
# WARNING! All changes made in this file will be lost! 

from PyQt5 import QtCore, QtGui, QtWidgets 

class Ui_MainWindow(object): 
    def setupUi(self, MainWindow): 
     MainWindow.setObjectName("MainWindow") 
     MainWindow.resize(526, 373) 

     self.centralwidget = QtWidgets.QWidget(MainWindow) 
     self.centralwidget.setObjectName("centralwidget") 
     self.verticalLayout = QtWidgets.QVBoxLayout(self.centralwidget) 
     self.verticalLayout.setObjectName("verticalLayout") 
     self.subreddits_input_layout = QtWidgets.QHBoxLayout() 
     self.subreddits_input_layout.setObjectName("subreddits_input_layout") 
     self.label_subreddits = QtWidgets.QLabel(self.centralwidget) 
     self.label_subreddits.setObjectName("label_subreddits") 
     self.subreddits_input_layout.addWidget(self.label_subreddits) 
     self.edit_subreddits = QtWidgets.QLineEdit(self.centralwidget) 
     self.edit_subreddits.setObjectName("edit_subreddits") 
     self.subreddits_input_layout.addWidget(self.edit_subreddits) 
     self.verticalLayout.addLayout(self.subreddits_input_layout) 
     self.label_submissions_list = QtWidgets.QLabel(self.centralwidget) 
     self.label_submissions_list.setObjectName("label_submissions_list") 
     self.verticalLayout.addWidget(self.label_submissions_list) 
     self.list_submissions = QtWidgets.QListWidget(self.centralwidget) 
     self.list_submissions.setBatchSize(1) 
     self.list_submissions.setObjectName("list_submissions") 
     self.verticalLayout.addWidget(self.list_submissions) 
     self.progress_bar = QtWidgets.QProgressBar(self.centralwidget) 
     self.progress_bar.setProperty("value", 0) 
     self.progress_bar.setObjectName("progress_bar") 
     self.verticalLayout.addWidget(self.progress_bar) 
     self.buttons_layout = QtWidgets.QHBoxLayout() 
     self.buttons_layout.setObjectName("buttons_layout") 
     self.btn_stop = QtWidgets.QPushButton(self.centralwidget) 
     self.btn_stop.setEnabled(False) 
     self.btn_stop.setObjectName("btn_stop") 
     self.buttons_layout.addWidget(self.btn_stop) 
     self.btn_start = QtWidgets.QPushButton(self.centralwidget) 
     self.btn_start.setObjectName("btn_start") 
     self.buttons_layout.addWidget(self.btn_start) 
     self.verticalLayout.addLayout(self.buttons_layout) 
     MainWindow.setCentralWidget(self.centralwidget) 

     self.retranslateUi(MainWindow) 
     QtCore.QMetaObject.connectSlotsByName(MainWindow) 

    def retranslateUi(self, MainWindow): 
     _translate = QtCore.QCoreApplication.translate 
     MainWindow.setWindowTitle(_translate("MainWindow", "Threading Tutorial - nikolak.com ")) 
     self.label_subreddits.setText(_translate("MainWindow", "Subreddits:")) 
     self.edit_subreddits.setPlaceholderText(_translate("MainWindow", "python,programming,linux,etc (comma separated)")) 
     self.label_submissions_list.setText(_translate("MainWindow", "Submissions:")) 
     self.btn_stop.setText(_translate("MainWindow", "Stop")) 
     self.btn_start.setText(_translate("MainWindow", "Start")) 

и основной сценарий (main.py):

from PyQt5 import QtWidgets 
from PyQt5.QtCore import QThread, pyqtSignal, QObject 
import sys 
import newdesign 
import urllib.request 
import json 
import time 


class getPostsThread(QThread): 
    def __init__(self, subreddits): 
     """ 
     Make a new thread instance with the specified 
     subreddits as the first argument. The subreddits argument 
     will be stored in an instance variable called subreddits 
     which then can be accessed by all other class instance functions 

     :param subreddits: A list of subreddit names 
     :type subreddits: list 
     """ 
     QThread.__init__(self) 
     self.subreddits = subreddits 

    def __del__(self): 
     self.wait() 

    def _get_top_post(self, subreddit): 
     """ 
     Return a pre-formatted string with top post title, author, 
     and subreddit name from the subreddit passed as the only required 
     argument. 

     :param subreddit: A valid subreddit name 
     :type subreddit: str 
     :return: A string with top post title, author, 
        and subreddit name from that subreddit. 
     :rtype: str 
     """ 
     url = "https://www.reddit.com/r/{}.json?limit=1".format(subreddit) 
     headers = {'User-Agent': '[email protected] tutorial code'} 
     request = urllib.request.Request(url, header=headers) 
     response = urllib.request.urlopen(request) 
     data = json.load(response) 
     top_post = data['data']['children'][0]['data'] 
     return "'{title}' by {author} in {subreddit}".format(**top_post) 

    def run(self): 
     """ 
     Go over every item in the self.subreddits list 
     (which was supplied during __init__) 
     and for every item assume it's a string with valid subreddit 
     name and fetch the top post using the _get_top_post method 
     from reddit. Store the result in a local variable named 
     top_post and then emit a pyqtSignal add_post(QString) where 
     QString is equal to the top_post variable that was set by the 
     _get_top_post function. 

     """ 
     for subreddit in self.subreddits: 
      top_post = self._get_top_post(subreddit) 
      self.emit(pyqtSignal('add_post(QString)'), top_post) 
      self.sleep(2) 


class ThreadingTutorial(QtWidgets.QMainWindow, newdesign.Ui_MainWindow): 
    """ 
    How the basic structure of PyQt GUI code looks and behaves like is 
    explained in this tutorial 
    http://nikolak.com/pyqt-qt-designer-getting-started/ 
    """ 

    def __init__(self): 
     super(self.__class__, self).__init__() 
     self.setupUi(self) 
     self.btn_start.clicked.connect(self.start_getting_top_posts) 

    def start_getting_top_posts(self): 
     # Get the subreddits user entered into an QLineEdit field 
     # this will be equal to '' if there is no text entered 
     subreddit_list = str(self.edit_subreddits.text()).split(',') 
     if subreddit_list == ['']: # since ''.split(',') == [''] we use that to check 
            # whether there is anything there to fetch from 
            # and if not show a message and abort 
      QtWidgets.QMessageBox.critical(self, "No subreddits", 
             "You didn't enter any subreddits.", 
             QtWidgets.QMessageBox.Ok) 
      return 
     # Set the maximum value of progress bar, can be any int and it will 
     # be automatically converted to x/100% values 
     # e.g. max_value = 3, current_value = 1, the progress bar will show 33% 
     self.progress_bar.setMaximum(len(subreddit_list)) 
     # Setting the value on every run to 0 
     self.progress_bar.setValue(0) 

     # We have a list of subreddits which we use to create a new getPostsThread 
     # instance and we pass that list to the thread 
     self.get_thread = getPostsThread(subreddit_list) 

     # Next we need to connect the events from that thread to functions we want 
     # to be run when those pyqtSignals get fired 

     # Adding post will be handeled in the add_post method and the pyqtSignal that 
     # the thread will emit is pyqtSignal("add_post(QString)") 
     # the rest is same as we can use to connect any pyqtSignal 
     self.connect(self.get_thread, pyqtSignal("add_post(QString)"), self.add_post) 

     # This is pretty self explanatory 
     # regardless of whether the thread finishes or the user terminates it 
     # we want to show the notification to the user that adding is done 
     # and regardless of whether it was terminated or finished by itself 
     # the finished pyqtSignal will go off. So we don't need to catch the 
     # terminated one specifically, but we could if we wanted. 
     self.connect(self.get_thread, pyqtSignal("finished()"), self.done) 

     # We have all the events we need connected we can start the thread 
     self.get_thread.start() 
     # At this point we want to allow user to stop/terminate the thread 
     # so we enable that button 
     self.btn_stop.setEnabled(True) 
     # And we connect the click of that button to the built in 
     # terminate method that all QThread instances have 
     self.btn_stop.clicked.connect(self.get_thread.terminate) 
     # We don't want to enable user to start another thread while this one is 
     # running so we disable the start button. 
     self.btn_start.setEnabled(False) 

    def add_post(self, post_text): 
     """ 
     Add the text that's given to this function to the 
     list_submissions QListWidget we have in our GUI and 
     increase the current value of progress bar by 1 

     :param post_text: text of the item to add to the list 
     :type post_text: str 
     """ 
     self.list_submissions.addItem(post_text) 
     self.progress_bar.setValue(self.progress_bar.value()+1) 

    def done(self): 
     """ 
     Show the message that fetching posts is done. 
     Disable Stop button, enable the Start one and reset progress bar to 0 
     """ 
     self.btn_stop.setEnabled(False) 
     self.btn_start.setEnabled(True) 
     self.progress_bar.setValue(0) 
     QtWidgets.QMessageBox.information(self, "Done!", "Done fetching posts!") 


def main(): 
    app = QtWidgets.QApplication(sys.argv) 
    form = ThreadingTutorial() 
    form.show() 
    app.exec_() 

if __name__ == '__main__': 
    main() 

Теперь я получаю следующее сообщение об ошибке:

AttributeError: 'ThreadingTutorial' object has no attribute 'connect'

Может ли кто-нибудь мне рассказать как это исправить? Любая помощь, как всегда, очень ценится.

ответ

3

Использование QObject.connect() и подобное в PyQt4 известен как «Старые сигналы типа», и is not supported in PyQt5 больше, он поддерживает только "New style signals", который уже в PyQt4 был рекомендуемым способом для подключения сигналов.

В PyQt5 вам необходимо непосредственно использовать методы связанного сигнала , например. вместо:

self.emit(pyqtSignal('add_post(QString)'), top_post) 
... 
self.connect(self.get_thread, pyqtSignal("add_post(QString)"), self.add_post) 
self.connect(self.get_thread, pyqtSignal("finished()"), self.done) 

использования:

self.add_post.emit(top_post) 
... 
self.get_thread.add_post.connect(self.add_post) 
self.get_thread.finished.connect(self.done) 

Однако для этой работы вам необходимо явно определить add_post сигнал на ваш getPostsThread первый, в противном случае вы получите сообщение об ошибке атрибута.

class getPostsThread(QThread): 
    add_post = pyqtSignal(str) 
    ... 

В PyQt4 со старыми сигналами типа при использовании сигнала он был automatically defined, это сейчас должно быть сделано явным образом.

+0

Большое спасибо за это очень хорошее объяснение! – dliv

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