Develop Reference

How do I get events for QListWidgetItem becoming visible in PyQT5

I'm using PyQT5 and currently have a QListWidgetItem that has a custom icon of an image thumbnail.
class ThumbWidget(QListWidgetItem):
def __init__(self, filename: str, database):
QListWidgetItem.__init__(self)
self.filename = filename
self.database = database
self.setText(basename(self.filename))
standard_file_icon = QWidget().style().standardIcon(QStyle.SP_FileIcon)
self.setIcon(standard_file_icon)
self.setSizeHint(QSize(THUMB_WIDTH, THUMB_HEIGHT + FILENAME_MARGIN))
def __str__(self):
return f'Thumbnail for {self.filename}'
def load_thumb(self):
metadata = self.database.file_metadata(self.filename)
img_thumb = metadata['thumb']
if img_thumb:
img = QPixmap()
img.loadFromData(img_thumb, 'JPEG')
self.setIcon(QIcon(img))
As you can see, it starts off using a SP_FileIcon by default and loads in a Thumbnail. Currently this happens in the QListWidget using a thread to load all the thumbnails at once.
class MediaBrowser(QListWidget):
def __init__(self, database: Database, viewtab, dir_path):
QListWidget.__init__(self)
self.log = logging.getLogger('mediahug')
self.database = database
self.viewtab = viewtab
self.current_directory = dir_path
# self.current_file_widgets = []
self.thumb_loader_thread = None
...
...
...
def thumb_load_progress(self, msg):
self.log.debug(msg)
if msg == 'thumb-load':
self.viewtab.scan_label_action.setVisible(True)
self.viewtab.scan_thumb_progress_action.setVisible(True)
elif msg == 'thumb-finish':
self.log.debug('Thumb Scan Finished. Hiding Progressbar')
self.viewtab.scan_label_action.setVisible(False)
self.viewtab.scan_thumb_progress_action.setVisible(False)
elif type(msg) == float:
self.viewtab.scan_thumb_progress.setValue(int(msg * 100))
else:
self.log.warning(f'Unknown thumb loader progress message {msg}')
def load_files(self, dir_path):
if self.thumb_loader_thread and self.thumb_loader_thread.isRunning():
self.log.info('Killing Previous Thumbnail Loading Thread')
self.thumb_loader_thread.requestInterruption()
self.thumb_loader_thread.wait(sys.maxsize)
self.log.info('Previous Thumbnail Thread Done')
self.clear()
# Load New File widgets
onlyfiles = [f for f in listdir(dir_path) if isfile(join(dir_path, f))]
for f in onlyfiles:
vid = join(dir_path, f)
self.log.debug(f"Creating File/Thumb Widget {vid}")
self.addItem(ThumbWidget(vid, self.database))
self.thumb_loader_thread = ThumbLoaderThread(self.all_files(), dir_path)
self.thumb_loader_thread.signal.connect(self.thumb_load_progress)
self.thumb_loader_thread.start()
This can take a long time and load a lot of thumbnails for large collections. I would like to ditch that thread entirely and instead, load the thumbnails lazily/more efficiently. The QListWidget gets wrapped inside of a QScrollArea. Is there any means, either via the QListWidget widget or within the QListWidgetItem, to receive events when a particular list item comes into view and opportunistically load the thumbnail at that point? I've looked through the API and can't seem to find anything.

PyQt5: QProgressBar will not update

I have an application where one of its functions is to use pytube to download YouTube videos. Everything works perfectly except for updating the QProgressBar with the download progress. Please see below code:
import pytube
import PyQt5.QtWidgets as QtWidgets
import PyQt5.QtCore as QtCore
class Worker(QtCore.QObject):
finished = QtCore.pyqtSignal()
progress = QtCore.pyqtSignal(str, int, int)
def __init__(self, url, save_path, fname):
super(Worker, self).__init__()
self.url = url
self.save_path = save_path
self.fname = fname
self.perc_dl = 0
self.download_video()
def run(self):
if self.perc_dl < 100:
self.progress.emit('Downloading: {}%'.format(str(self.perc_dl)), int(self.perc_dl), 100)
print(self.perc_dl)
else:
self.progress.emit('Done!', 100, 100)
self.finished.emit()
def download_video(self):
yt = pytube.YouTube(self.url, on_progress_callback=self.progress_function)
stream = yt.streams.filter(progressive=True, file_extension='mp4').get_highest_resolution()
stream.download(output_path=self.save_path, filename=self.fname)
def progress_function(self, stream, chunk, bytes_remaining):
curr = stream.filesize - bytes_remaining
per_downloaded = round((curr / stream.filesize) * 100, 1)
self.perc_dl = per_downloaded
self.run()
class DownloadFromYT(QtWidgets.QDialog):
def __init__(self, url, save_path, fname):
super(DownloadFromYT, self).__init__()
self.url = url
self.save_path = save_path
self.fname = fname
self.vLayoutMaster = QtWidgets.QVBoxLayout()
self.hLayout = QtWidgets.QHBoxLayout()
self.hLayout.setAlignment(QtCore.Qt.AlignRight)
self.label = QtWidgets.QLabel()
self.label.setText('Downloading video')
self.pBar = QtWidgets.QProgressBar()
self.pBar.setInvertedAppearance(True)
self.pBar.setTextVisible(True)
self.pBar.setFixedWidth(200)
self.pBar.setAlignment(QtCore.Qt.AlignCenter)
self.pBar.setMaximum(100)
self.pBar.setFormat('Downloading: ')
self.noButton = QtWidgets.QPushButton('No')
self.noButton.setFixedWidth(50)
self.noButton.hide()
self.yesButton = QtWidgets.QPushButton('Yes')
self.yesButton.setFixedWidth(50)
self.yesButton.hide()
self.vLayoutMaster.addWidget(self.label)
self.vLayoutMaster.addSpacing(10)
self.vLayoutMaster.addWidget(self.pBar)
self.vLayoutMaster.addSpacing(20)
self.hLayout.addWidget(self.noButton)
self.hLayout.addWidget(self.yesButton)
self.vLayoutMaster.addLayout(self.hLayout)
# Signals / slots
self.noButton.clicked.connect(self.reject)
self.yesButton.clicked.connect(self.accept)
# Widget
self.setLayout(self.vLayoutMaster)
self.setWindowTitle('Downloading')
self.setFixedSize(250, 100)
self.show()
# Init download
self.run_thread(url, save_path, fname)
def run_thread(self, url, save_path, fname):
self.thrd = QtCore.QThread()
self.worker = Worker(url, save_path, fname)
self.worker.moveToThread(self.thrd)
self.thrd.start()
self.thrd.started.connect(self.worker.run)
self.worker.finished.connect(self.thrd.quit)
self.worker.finished.connect(self.worker.deleteLater)
self.worker.progress.connect(self.show_progress)
self.thrd.finished.connect(self.thrd.deleteLater)
def show_progress(self, label, n, total):
self.pBar.setFormat(label)
self.pBar.setMaximum(total)
self.pBar.setValue(n)
QtCore.QCoreApplication.processEvents()
if label == 'Done!':
self.thrd.quit()
self.noButton.show()
self.yesButton.show()
self.label.setText('Video has been downloaded. Would you like to set the chosen\n'
'file path as the "Local file" path?')
I have used this basic structure in other parts of my application to display and update a progress bar with no issues, however for some reason here, self.pBar refuses to update when the progress signal is emitted from the Worker class. As you can see, I have a print() statement in the run method to check that the code is actually entering that if block and periodically printing out the download progress to the console, which it is. The application updates when the thread has finished running, so I get the final, completely filled progress bar, but in between the start and end the progress bar does not update as expected.
Any help would be greatly appreciated!

The problem seems to be that despite all your effort to wire up all that thread-worker components correctly, you are still running self.download_video() in the main (UI) thread. And therefore it is blocking refreshing of the UI. If you want to run in in the secondary thread, you must start it in Worker.run() function and not in the Worker constructor. If you wire up all threading correctly, then you should not need to call processEvents() at all to refresh UI.
If you are unsure about the thread in which the download function runs, print the thread ID in your print function and compare it to thread id of the main UI thread. Have a look at https://doc.qt.io/qt-5/qthread.html#currentThread

Running a function when a widget window is brought to the front?

I'm building a gui front-end for a project I've been working on, and I'm having trouble figuring out this specific aspect of PyQT. Long ago there was a post that I had that I think would've solved the problem but I can't quite find it.
Regardless, I have the following files, main.py and playlistcreator.py respectively:
(main.py)
import getpass
import playlistcreator
import os
import sys
import sip
sip.setapi('QString', 2)
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
# Window class
class Window(QWidget):
def __init__(self): # constructor for Window (passes "self" -aka Window- to __init__ to initialize it)
super(Window, self).__init__() # inherits from QMainWindow
self.setGeometry(50, 50, 300, 150) # Set window dimensions
self.setWindowTitle("Google Music Playlist Transfer") # Set window title
self.setWindowIcon(QIcon('gmusic.png')) # Set window icon
self.login = QWidget() # login widget ("front page")
self.processing = QWidget() # on successful login - being processing data
self.file_inputs = QWidget() # after processing, ask user where they would like to store data
# call functions
self.loginUI()
self.processingUI()
self.file_inputsUI()
# create stacked widget and add layouts to stack
self.Stack = QStackedWidget(self)
self.Stack.addWidget(self.login)
self.Stack.addWidget(self.processing)
self.Stack.addWidget(self.file_inputs)
main_box = QHBoxLayout(self)
main_box.addWidget(self.Stack)
self.setLayout(main_box)
self.show()
def loginUI(self):
# Set email field
self.email = QLineEdit()
self.email.setMaxLength(110)
self.email.setAlignment(Qt.AlignLeft)
# Set password field
self.pwd = QLineEdit()
self.pwd.setAlignment(Qt.AlignLeft)
self.pwd.setEchoMode(QLineEdit.Password)
# Form layout
form_layout = QFormLayout()
form_layout.addRow("Email: ", self.email)
form_layout.addRow("Password: ", self.pwd)
# Login button
self.login_btn = QPushButton("Login", self) # login button
self.login_btn.clicked.connect(self.process_login) # tell button what to do
self.login_btn.resize(self.login_btn.sizeHint())
# Quit button
self.quit_btn = QPushButton("Exit", self) # exit button
self.quit_btn.clicked.connect(self.close_application) # tell button what to do
# Error label layout
self.error_layout = QHBoxLayout()
# Button box layout
button_box = QHBoxLayout()
button_box.addStretch(1)
button_box.addWidget(self.login_btn)
button_box.addWidget(self.quit_btn)
# input layout (main layout for "home")
input_box = QVBoxLayout()
input_box.addLayout(self.error_layout)
input_box.addLayout(form_layout)
input_box.addLayout(button_box)
self.login.setLayout(input_box)
def processingUI(self):
# setup layout
layout = QHBoxLayout()
# alert user that we're grabbing track data
self.progress_label = QLabel("Grabbing tracks from Google Music. . .")
self.progress_label.setStyleSheet("color: rgb(0, 100, 0);")
layout.addWidget(self.progress_label)
# Get users list of "thumbs up" tracks from Google Music
# set layout
favorite_tracks = self.get_tracks
self.processing.setLayout(layout)
def file_inputsUI(self):
layout = QFormLayout()
# Set text field for directory
self.dir_textbox = QTextEdit(self)
# Add textbox to layout
layout.addRow("Music Directory: ", self.dir_textbox)
self.file_inputs.setLayout(layout)
def close_application(self):
confirm = QMessageBox.question(self, 'Exit Confirmation',
"Are you sure you want to exit?",
QMessageBox.Yes | QMessageBox.No)
if confirm == QMessageBox.Yes:
sys.exit()
else:
pass
def process_login(self):
email_input = str(self.email.text())
pwd_input = str(self.pwd.text())
login_successful = playlistcreator.login(email_input, pwd_input)
if login_successful:
self.Stack.setCurrentIndex(1)
else:
self.error_label = QLabel("Please check your email/password!")
self.error_label.setStyleSheet("color: rgb(255, 0, 0);")
self.error_layout.addWidget(self.error_label)
def get_tracks(self):
tracks = playlistcreator.get_favorite_tracks()
print("You have ", len(tracks), " favorite tracks!")
return tracks
# def open_dir_dialog(self):
# directory = QFileDialog.getExistingDirectory(self, 'Select USB Drive Location')
# self.myTextBox.setText(fileName)
def main():
# Create an PyQT5 application object.
app = QApplication(sys.argv)
GUI = Window()
sys.exit(app.exec_())
# # Input Music Directory
# music_dir = input("Please put the path to your music folder: ")
# list_of_paths = playlistcreator.findmp3(music_dir, favorite_tracks)
# # Input playlist file save location
# playlist_path = input("Where would you like to save the playlist?: ")
# playlist_name = input("What would you like to name the playlist? ")
# playlist_name += ".m3u8"
# # Testing appending file extension to string
# playlistcreator.addtoplaylist(list_of_paths, playlist_path, playlist_name)
# playlistcreator.logout()
main()
(playlistcreator.py)
import os
from gmusicapi import Mobileclient
from mutagen.easyid3 import EasyID3
api = Mobileclient()
songCount = 0
favorite_files_path = []
logged_in = False
def login(email, password):
library = []
if "#" not in email:
email += "#gmail.com"
logged_in = api.login(email, password, Mobileclient.FROM_MAC_ADDRESS)
return logged_in
def get_favorite_tracks():
print("Getting songs from Google Music. . .")
library = api.get_all_songs()
print("There are", len(library), "items in your music library")
good_songs = [song for song in library if song['rating'] == '5']
print("You have", len(good_songs), "favorite tracks!")
return good_songs
def logout():
api.logout()
def findmp3(rootFolder, favoriteTracks):
print("Searching for favorite tracks. . .")
for directory, subdirectory, files in os.walk(rootFolder, topdown=False): # for all files in directory
global songCount
global favorite_files_path
for mp3 in files: # for files in
if mp3.endswith(".mp3"): # if file ends with .mp3
file_path = os.path.join(directory, mp3) # concatenate to create full path
try:
file_tags = EasyID3(file_path) # grab file tags from mp3 file
except:
file_tags = EasyID3() # create tags if none are found
file_tags.save(file_path) # save file to have new tags
if "title" in file_tags:
fileTitle = file_tags["title"][0] # TIT2 = corresponding tag in mutagen for song title
else:
fileTitle = "None"
if "artist" in file_tags:
fileArtist = file_tags["artist"][0] # TPE = corresponding tag in mutagen for artist
else:
fileArtist = "None"
if "album" in file_tags:
fileAlbum = file_tags["album"][0] # TALB = corresponding tag in mutagen for album
else:
fileAlbum = "None"
for track in favoriteTracks:
gMusicTitle = track["title"]
gMusicArtist = track["artist"]
gMusicAlbum = track["album"]
if fileTitle in gMusicTitle and fileArtist in gMusicArtist and fileAlbum in gMusicAlbum: # if file tags (artist, album, title) match gMusic tags
songCount += 1
if songCount == 1:
print("Found 1 song")
else:
print("Found", songCount, "songs") # print updated count of found tracks
favorite_files_path.append(file_path) # add all found files to a list (via their paths)
break # break out of "for track in favorite tracks"
return favorite_files_path
def addtoplaylist(paths, playlist_path, playlist_name):
# Open file (or create if it does not exist)
# change to given directory
try:
os.chdir(playlist_path)
except Exception as err:
print(err)
# open file - if it does not exist, create it
with open(playlist_name, 'a+', encoding="UTF-8") as playlistFile:
print("Adding tracks...", end="")
for track in paths:
print(".", end="")
playlistFile.write(track + '\n')
playlistFile.close()
The problem I've been running into is when the user logs in they hit the processingUI window (which states that the program is grabbing all their tracks from Google) but it doesn't actually seem to be running the get_tracks() method (which is what actually gets the user's tracks from Google), as the program hangs there and doesn't do anything.
I've tested the program without a GUI using straight command line, and it works flawlessly, but I'm not sure what the issue is with the GUI - do I need to thread the execution to start when the proper "window" is brought to the front?

Q Network Access manager in pyQt Python (Segmentation Fault Core Dumped)

i have developed an application using pyQt in python and using a web browser and a table to show the headers coming with the browser request.
here is my code:-
import sys
from PyQt4.QtGui import QApplication, QTableWidget, QTableWidgetItem
from PyQt4.QtCore import QUrl
from PyQt4.QtWebKit import QWebView, QWebPage
from PyQt4.QtGui import QGridLayout, QLineEdit, QWidget, QHeaderView
from PyQt4.QtNetwork import QNetworkAccessManager, QNetworkRequest
class RequestsTable(QTableWidget):
header = ["url", "status", "content-type","cookies","user_agent"]
def __init__(self):
super(RequestsTable, self).__init__()
self.setColumnCount(5)
self.setHorizontalHeaderLabels(self.header)
header = self.horizontalHeader()
header.setStretchLastSection(True)
def update(self, data):
last_row = self.rowCount()
next_row = last_row + 1
self.setRowCount(next_row)
for col, dat in enumerate(data, 0):
if not dat:
continue
self.setItem(last_row, col, QTableWidgetItem(dat))
class Manager(QNetworkAccessManager):
def __init__(self, table):
QNetworkAccessManager.__init__(self)
self.finished.connect(self._finished)
self.table = table
def _finished(self, reply):
user_agent = str(reply.request().rawHeader("User-Agent"))
headers = reply.rawHeaderPairs()
headers = {str(k):str(v) for k,v in headers}
content_type = headers.get("Content-Type")
url = reply.url().toString()
status = reply.attribute(QNetworkRequest.HttpStatusCodeAttribute)
status, ok = status.toInt()
cookies = headers.get("Set-Cookie")
self.table.update([url, str(status), content_type,cookies,user_agent])
if __name__ == "__main__":
app = QApplication(sys.argv)
grid = QGridLayout()
browser = QWebView()
browser.load(QUrl("http://www.indiatimes.com/"))
def on_html_available():
page = QWebPage()
page.setNetworkAccessManager(manager)
# problem is here
browser.setPage(page)
# if i dont use above line then it don't show any error but the headers don't get append in the table but if i use the above line it shows me the error segmentation fault
browser.loadFinished.connect(on_html_available)
requests_table = RequestsTable()
manager = Manager(requests_table)
grid.addWidget(browser, 3, 0)
grid.addWidget(requests_table, 4, 0)
main_frame = QWidget()
main_frame.setLayout(grid)
main_frame.show()
sys.exit(app.exec_())
but the above code is showing me the error
"core dumped segmentation fault"?
what may be the problem ? please help me in resolving this issue.

Its showing this error because you are again setting the browser's page on html finished, which is wrong, to access network access manager you should first take the manager then set the manager with page and then set the browser page. let me know if you don't get this.

Refresh QTextEdit in PyQt

Im writing a PyQt app that takes some input in one widget, and then processes some text files.
What ive got at the moment is when the user clicks the "process" button a seperate window with a QTextEdit in it pops up, and ouputs some logging messages.
On Mac OS X this window is refreshed automatically and you cna see the process.
On Windows, the window reports (Not Responding) and then once all the proccessing is done, the log output is shown. Im assuming I need to refresh the window after each write into the log, and ive had a look around at using a timer. etc, but havnt had much luck in getting it working.
Below is the source code. It has two files, GUI.py which does all the GUI stuff and MOVtoMXF that does all the processing.
GUI.py
import os
import sys
import MOVtoMXF
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class Form(QDialog):
def process(self):
path = str(self.pathBox.displayText())
if(path == ''):
QMessageBox.warning(self, "Empty Path", "You didnt fill something out.")
return
xmlFile = str(self.xmlFileBox.displayText())
if(xmlFile == ''):
QMessageBox.warning(self, "No XML file", "You didnt fill something.")
return
outFileName = str(self.outfileNameBox.displayText())
if(outFileName == ''):
QMessageBox.warning(self, "No Output File", "You didnt do something")
return
print path + " " + xmlFile + " " + outFileName
mov1 = MOVtoMXF.MOVtoMXF(path, xmlFile, outFileName, self.log)
self.log.show()
rc = mov1.ScanFile()
if( rc < 0):
print "something happened"
#self.done(0)
def __init__(self, parent=None):
super(Form, self).__init__(parent)
self.log = Log()
self.pathLabel = QLabel("P2 Path:")
self.pathBox = QLineEdit("")
self.pathBrowseB = QPushButton("Browse")
self.pathLayout = QHBoxLayout()
self.pathLayout.addStretch()
self.pathLayout.addWidget(self.pathLabel)
self.pathLayout.addWidget(self.pathBox)
self.pathLayout.addWidget(self.pathBrowseB)
self.xmlLabel = QLabel("FCP XML File:")
self.xmlFileBox = QLineEdit("")
self.xmlFileBrowseB = QPushButton("Browse")
self.xmlLayout = QHBoxLayout()
self.xmlLayout.addStretch()
self.xmlLayout.addWidget(self.xmlLabel)
self.xmlLayout.addWidget(self.xmlFileBox)
self.xmlLayout.addWidget(self.xmlFileBrowseB)
self.outFileLabel = QLabel("Save to:")
self.outfileNameBox = QLineEdit("")
self.outputFileBrowseB = QPushButton("Browse")
self.outputLayout = QHBoxLayout()
self.outputLayout.addStretch()
self.outputLayout.addWidget(self.outFileLabel)
self.outputLayout.addWidget(self.outfileNameBox)
self.outputLayout.addWidget(self.outputFileBrowseB)
self.exitButton = QPushButton("Exit")
self.processButton = QPushButton("Process")
self.buttonLayout = QHBoxLayout()
#self.buttonLayout.addStretch()
self.buttonLayout.addWidget(self.exitButton)
self.buttonLayout.addWidget(self.processButton)
self.layout = QVBoxLayout()
self.layout.addLayout(self.pathLayout)
self.layout.addLayout(self.xmlLayout)
self.layout.addLayout(self.outputLayout)
self.layout.addLayout(self.buttonLayout)
self.setLayout(self.layout)
self.pathBox.setFocus()
self.setWindowTitle("MOVtoMXF")
self.connect(self.processButton, SIGNAL("clicked()"), self.process)
self.connect(self.exitButton, SIGNAL("clicked()"), self, SLOT("reject()"))
self.ConnectButtons()
class Log(QTextEdit):
def __init__(self, parent=None):
super(Log, self).__init__(parent)
self.timer = QTimer()
self.connect(self.timer, SIGNAL("timeout()"), self.updateText())
self.timer.start(2000)
def updateText(self):
print "update Called"
AND MOVtoMXF.py
import os
import sys
import time
import string
import FileUtils
import shutil
import re
class MOVtoMXF:
#Class to do the MOVtoMXF stuff.
def __init__(self, path, xmlFile, outputFile, edit):
self.MXFdict = {}
self.MOVDict = {}
self.path = path
self.xmlFile = xmlFile
self.outputFile = outputFile
self.outputDirectory = outputFile.rsplit('/',1)
self.outputDirectory = self.outputDirectory[0]
sys.stdout = OutLog( edit, sys.stdout)
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)
self.edit.insertPlainText( m )
if self.color:
self.edit.setTextColor(tc)
if self.out:
self.out.write(m)
self.edit.show()
If any other code is needed (i think this is all that is needed) then just let me know.
Any Help would be great.
Mark

It looks like your are running an external program, capturing its output into a QTextEdit. I didn't see the code of Form.process, but I am guessing on windows your function waits for the external program to finish, then quickly dumps everything to the QTextEdit.
If your interface really is waiting for the other process to finish, then it will hang in the manner you describe. You'll need to look at subprocess or perhaps even popen to get the program's output in a "non-blocking" manner.
The key to avoiding "(Not Responding)" is to call QApplication.processEvents a few times every few seconds. The QTimer is not going to help in this case, because if Qt cannot process its events, it cannot call any signal handlers.