Scrolling Text in PyQt?

Question

I'm trying to have text from feedparser scroll across the screen from right to left. I'm using PyQt5, I'm not sure how to go about adding this feature. What I want to display is below

import feedparser
sports = feedparser.parse('http://rssfeeds.usatoday.com/UsatodaycomSports-TopStories')
for e in sports['entries']:
news = (e.get('title', ''))

I'm looking for a continuous scrolling until all the news headlines are read and then the page is reloaded to get the most recent headlines or just reread whats already there. Thanks!

Answer 1

You can use QTimeLine to show a continously scrolling slice of the news in a label. I implemented it in a little gui to try, if other functions in the app are blocked while QTimeLine is running:

import feedparser
import sys
from PyQt5 import QtWidgets, QtCore

class MyWidget(QtWidgets.QWidget):
    def __init__(self, parent = None):
        QtWidgets.QWidget.__init__(self, parent)
        self.setGeometry(200, 200, 800, 600)
        self.textLabel = QtWidgets.QLabel('')               # label showing some text
        self.uButton = QtWidgets.QPushButton('upper Button')    
        self.lButton =  QtWidgets.QPushButton('lower Button')
        self.label = QtWidgets.QLabel('')                   # label showing the news
        self.label.setAlignment(QtCore.Qt.AlignRight)           # text starts on the right
        self.layout = QtWidgets.QVBoxLayout()
        self.layout.addWidget(self.textLabel)
        self.layout.addWidget(self.uButton)
        self.layout.addWidget(self.lButton)
        self.layout.addWidget(self.label)
        self.layout.setStretch(0, 3)
        self.layout.setStretch(1, 3)
        self.layout.setStretch(2, 3)
        self.layout.setStretch(3, 1)         
        self.setLayout(self.layout)

        self.timeLine = QtCore.QTimeLine()  
        self.timeLine.setCurveShape(QtCore.QTimeLine.LinearCurve)                   # linear Timeline
        self.timeLine.frameChanged.connect(self.setText)
        self.timeLine.finished.connect(self.nextNews)           
        self.signalMapper = QtCore.QSignalMapper(self)
        self.signalMapper.mapped[str].connect(self.setTlText)
        self.uButton.clicked.connect(self.signalMapper.map)
        self.signalMapper.setMapping(self.uButton, self.uButton.text())
        self.lButton.clicked.connect(self.signalMapper.map)
        self.signalMapper.setMapping(self.lButton, self.lButton.text())

        self.feed()

    def feed(self):
        fm = self.label.fontMetrics()
        self.nl = int(self.label.width()/fm.averageCharWidth())     # shown stringlength
        news = []
        sports = feedparser.parse('http://rssfeeds.usatoday.com/UsatodaycomSports-TopStories')
        for e in sports['entries']:
            news.append(e.get('title', ''))
        appendix = ' '*self.nl                      # add some spaces at the end
        news.append(appendix)
        delimiter = '      +++      '                   # shown between the messages
        self.news = delimiter.join(news)
        newsLength = len(self.news)                 # number of letters in news = frameRange 
        lps = 4                                 # letters per second 
        dur = newsLength*1000/lps               # duration until the whole string is shown in milliseconds                                          
        self.timeLine.setDuration(dur)
        self.timeLine.setFrameRange(0, newsLength) 
        self.timeLine.start()

    def setText(self, number_of_frame):   
        if number_of_frame < self.nl:
            start = 0
        else:
            start = number_of_frame - self.nl
        text = '{}'.format(self.news[start:number_of_frame])        
        self.label.setText(text)

    def nextNews(self):
        self.feed()                             # start again

    def setTlText(self, text):
        string = '{} pressed'.format(text)
        self.textLabel.setText(string)

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    widget = MyWidget()
    widget.show()
    sys.exit(app.exec_())

Add PySide2 version:

import feedparser
import sys
from PySide2 import QtWidgets, QtCore

class MyWidget(QtWidgets.QWidget):
    def __init__(self, parent = None):
        QtWidgets.QWidget.__init__(self, parent)
        self.setGeometry(200, 200, 800, 600)
        self.textLabel = QtWidgets.QLabel('')               # label showing some text
        self.uButton = QtWidgets.QPushButton('upper Button')    
        self.lButton =  QtWidgets.QPushButton('lower Button')
        self.label = QtWidgets.QLabel('')                   # label showing the news
        self.label.setAlignment(QtCore.Qt.AlignRight)           # text starts on the right
        self.layout = QtWidgets.QVBoxLayout()
        self.layout.addWidget(self.textLabel)
        self.layout.addWidget(self.uButton)
        self.layout.addWidget(self.lButton)
        self.layout.addWidget(self.label)
        self.layout.setStretch(0, 3)
        self.layout.setStretch(1, 3)
        self.layout.setStretch(2, 3)
        self.layout.setStretch(3, 1)         
        self.setLayout(self.layout)

        self.timeLine = QtCore.QTimeLine()  
        self.timeLine.setCurveShape(QtCore.QTimeLine.LinearCurve)                  # linear Timeline
        self.timeLine.frameChanged.connect(self.setText)
        self.timeLine.finished.connect(self.nextNews)           
        self.signalMapper = QtCore.QSignalMapper(self)
        self.signalMapper.mapped[str].connect(self.setTlText)
        self.uButton.clicked.connect(self.signalMapper.map)
        self.signalMapper.setMapping(self.uButton, self.uButton.text())
        self.lButton.clicked.connect(self.signalMapper.map)
        self.signalMapper.setMapping(self.lButton, self.lButton.text())

        self.feed()

    def feed(self):
        fm = self.label.fontMetrics()
        self.nl = int(self.label.width()/fm.averageCharWidth())     # shown stringlength
        news = []
        sports = feedparser.parse('http://rssfeeds.usatoday.com/UsatodaycomSports-TopStories')
        for e in sports['entries']:
            news.append(e.get('title', ''))
        appendix = ' '*self.nl                      # add some spaces at the end
        news.append(appendix)
        delimiter = '      +++      '                   # shown between the messages
        self.news = delimiter.join(news)
        newsLength = len(self.news)                 # number of letters in news = frameRange 
        lps = 4                                 # letters per second 
        dur = newsLength*1000/lps               # duration until the whole string is shown in milliseconds                                          
        self.timeLine.setDuration(dur)
        self.timeLine.setFrameRange(0, newsLength) 
        self.timeLine.start()

    def setText(self, number_of_frame):   
        if number_of_frame < self.nl:
            start = 0
        else:
            start = number_of_frame - self.nl
        text = '{}'.format(self.news[start:number_of_frame])        
        self.label.setText(text)

    def nextNews(self):
        self.feed()                             # start again

    def setTlText(self, text):
        string = '{} pressed'.format(text)
        self.textLabel.setText(string)

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    widget = MyWidget()
    widget.show()
    sys.exit(app.exec_())