CODEWITHSUNDEEP
pythonpyqtqmlpyqt5python-3.6
ImRaphael
ImRaphael

Reputation: 206

PyQt load function on startup (qml loader)

Hi i have the following problem :

this is my working code 

import sys
from PyQt5.QtCore import QObject, QUrl, Qt
from PyQt5.QtWidgets import QApplication
from PyQt5.QtQml import QQmlApplicationEngine
import os
import vlc
from time import sleep

# define VLC instance
instance = vlc.Instance()

# Define VLC player
instance = vlc.Instance('--input-repeat=-1', '--fullscreen')

player = instance.media_player_new()


list_test = []
list_name = []


def prepare_url(url):

media = instance.media_new(url)
    player.set_media(media)


if __name__ == "__main__":
os.environ["QT_QUICK_CONTROLS_STYLE"] = "Material"
app = QApplication(sys.argv)

engine = QQmlApplicationEngine()
ctx = engine.rootContext()
ctx.setContextProperty("main", engine)
engine.load('SimpleQML.qml')

win = engine.rootObjects()[0]
win.show()
button = win.findChild(QObject, "playBtn")


def myFunction():
    print("A fine piece of text")



button.clicked.connect(myFunction)  # works on click
myFunction() #works with out clicking

sys.exit(app.exec_())

Now i would like to expand on that by doing the following code :

import sys
from PyQt5.QtCore import QObject, QUrl, Qt
from PyQt5.QtWidgets import QApplication
from PyQt5.QtQml import QQmlApplicationEngine
import os
import vlc
from time import sleep

# define VLC instance
instance = vlc.Instance()

# Define VLC player
instance = vlc.Instance('--input-repeat=-1', '--fullscreen')

player = instance.media_player_new()


list_test = []
list_name = []


def prepare_url(url):

media = instance.media_new(url)

player.set_media(media)


if __name__ == "__main__":
os.environ["QT_QUICK_CONTROLS_STYLE"] = "Material"
app = QApplication(sys.argv)

engine = QQmlApplicationEngine()
ctx = engine.rootContext()
ctx.setContextProperty("main", engine)
engine.load('SimpleQML.qml')

win = engine.rootObjects()[0]
win.show()
button = win.findChild(QObject, "playBtn")
comboBox = win.findChild(QObject, "comboBox")

def myFunction():
    print("das")

def list_fill():
    with open("config/stations.txt") as f:
        content = f.readlines()
        content = [x.strip() for x in content]
        list_t = [item.split("|")[0] for item in content if item]
        list_n = [item.split("|")[1] for item in content if item]
        del list_test[:]
        del list_name[:]
        comboBox.clear()
        for x in list_t:
            list_test.append(x)
        for x in list_n:
            list_name.append(x)

        addItems(list_name)

button.clicked.connect(myFunction)  # works too
myFunction()
list_fill()  #calling this crashes program
sys.exit(app.exec_())

and at the very end this is the error 

    das
Traceback (most recent call last):
 File "/home/flea/Desktop/quick qt/main.py", line 65, in <module>
  list_fill()
 File "/home/flea/Desktop/quick qt/main.py", line 55, in list_fill
 comboBox.clear()
AttributeError: 'QObject' object has no attribute 'clear'

i tried to do ti with hardcoded list, but list is not the problem, for some reason my combo box is not recognized by python.I am not sure what is the problem here. I can load my button and add a click event to it, (which works), but i cant add list to my comboBox.

here is my Qml

 import QtQuick 2.10
import QtQuick.Controls 2.1
import QtQuick.Window 2.2
import QtQuick.Controls.Material 2.3



ApplicationWindow {
id: applicationWindow
Material.theme: Material.Light
title: qsTr("Test Invoke")

width: 600
height: 500

Row {
    id: row
    width: 200
    height: 400
    anchors.left: parent.left
    anchors.leftMargin: 5
    anchors.top: parent.top
    anchors.topMargin: 5

    Button{
        id: playBtn


        objectName: "playBtn"
        text : "Play"
        checked: false
        padding: 6
        rightPadding: 8
        font.wordSpacing: 0
        font.pointSize: 10
        font.family: "Times New Roman"
        topPadding: 4
        highlighted: true
        Material.accent: Material.Red



    }

    Button {
        id: stopBtn
        objectName: "stopBtn"
        text: qsTr("Stop")
        anchors.left: playBtn.right
        anchors.leftMargin: 5
    }

    Button {
        id: stfBtn
        text: qsTr("Save")
        objectName: "stfBtn"
        anchors.left: stopBtn.right
        anchors.leftMargin: 5
    }

    Button {
        id: minimize
        objectName: "minBtn"
        text: qsTr("Min")
        anchors.left: stfBtn.right
        anchors.leftMargin: 5
    }
}

Column {
    id: column
    x: 135
    y: 100
    width: 200
    height: 400

    TextField {
        objectName: "nameText"
        id: nameText
        width: 300
        text: qsTr("")
    }

    TextField {
        objectName: "urlText"
        id: urlText
        width: 300
        text: qsTr("")
    }

    ComboBox {
        objectName: "comboBox"
        id: comboBox
        width: 200
    }
}

Slider {
    id: slide
    objectName: "slider"
    x: 160
    y: 311
    value: 0.5
}




}

Upvotes: 1

Views: 1444

Answers (1)

eyllanesc
eyllanesc

Reputation: 244202

It is not a good nor maintainable over time to instantiate an object created in QML from Python or C++.

The appropriate thing is to create an object in Python or C++ and send it to QML, and then create qproperties and slots that allow interacting with the QML.

In your case, I guess that list_fill tries to add data to the ComboBox, but the ComboBox does not have a clear method, so if you want to clean it, just pass it an empty list, or in your case pass it the new list.

On the other hand it is not elegant to call show(), it is best to set the visible property of ApplicationWindow to true.

main.py

import sys
import os

from PyQt5.QtCore import QObject, QUrl, Qt, pyqtSlot, pyqtSignal, pyqtProperty
from PyQt5.QtWidgets import QApplication
from PyQt5.QtQml import QQmlApplicationEngine

import vlc

# define VLC instance
instance = vlc.Instance()

# Define VLC player
instance = vlc.Instance('--input-repeat=-1', '--fullscreen')

player = instance.media_player_new()


list_test = []
list_name = []

def prepare_url(url):
    media = instance.media_new(url)
    player.set_media(media)

class Manager(QObject):
    stationsChanged = pyqtSignal()
    currentStationChanged = pyqtSignal()
    def __init__(self):
        QObject.__init__(self)
        self.m_stations = []
        self.m_currentStation = ""
        self.currentStationChanged.connect(self.on_currentStationChanged)

    @pyqtProperty(str, notify=currentStationChanged)
    def currentStation(self):
        return self.m_currentStation

    @currentStation.setter
    def currentStation(self, val):
        if self.m_currentStation == val:
            return
        self.m_currentStation = val
        self.currentStationChanged.emit()

    @pyqtProperty(list, notify=stationsChanged)
    def stations(self):
        return self.m_stations

    @stations.setter
    def stations(self, val):
        if self.m_stations == val:
            return
        self.m_stations = val[:]
        self.stationsChanged.emit()

    @pyqtSlot()
    def play(self):
        print("play", self.currentStation)

    @pyqtSlot()
    def stop(self):
        print("stop")

    @pyqtSlot()
    def on_currentStationChanged(self):
        print(self.currentStation)

    def list_fill(self):
        l = []
        with open("config/stations.txt") as f:
            content = f.readlines()
            content = [x.strip() for x in content]
            list_t = [item.split("|")[0] for item in content if item]
            list_n = [item.split("|")[1] for item in content if item]
            l += list_t + list_n
        self.stations = l



if __name__ == "__main__":
    os.environ["QT_QUICK_CONTROLS_STYLE"] = "Material"
    app = QApplication(sys.argv)

    engine = QQmlApplicationEngine()
    manager = Manager()
    ctx = engine.rootContext()
    ctx.setContextProperty("Manager", manager)
    engine.load('main.qml')
    if not engine.rootObjects():
        sys.exit(-1)
    manager.list_fill()
    sys.exit(app.exec_())

main.qml

import QtQuick 2.10
import QtQuick.Controls 2.1
import QtQuick.Window 2.2
import QtQuick.Controls.Material 2.3

ApplicationWindow {
    id: applicationWindow
    Material.theme: Material.Light
    title: qsTr("Test Invoke")
    visible: true

    width: 600
    height: 500

    Row {
        id: row
        width: 200
        height: 400
        anchors.left: parent.left
        anchors.leftMargin: 5
        anchors.top: parent.top
        anchors.topMargin: 5

        Button{
            id: playBtn
            text : "Play"
            checked: false
            padding: 6
            rightPadding: 8
            font.wordSpacing: 0
            font.pointSize: 10
            font.family: "Times New Roman"
            topPadding: 4
            highlighted: true
            Material.accent: Material.Red
            onClicked: Manager.play()
        }

        Button {
            id: stopBtn
            text: qsTr("Stop")
            anchors.left: playBtn.right
            anchors.leftMargin: 5
            onClicked: Manager.stop()
        }

        Button {
            id: stfBtn
            text: qsTr("Save")
            objectName: "stfBtn"
            anchors.left: stopBtn.right
            anchors.leftMargin: 5
        }

        Button {
            id: minimize
            objectName: "minBtn"
            text: qsTr("Min")
            anchors.left: stfBtn.right
            anchors.leftMargin: 5
        }
    }

    Column {
        id: column
        x: 135
        y: 100
        width: 200
        height: 400

        TextField {
            id: nameText
            width: 300
            text: qsTr("")
        }

        TextField {
            id: urlText
            width: 300
            text: qsTr("")
        }

        ComboBox {
            id: comboBox
            width: 200
            model: Manager.stations
            onCurrentTextChanged: Manager.currentStation = currentText
        }
    }

    Slider {
        id: slider
        x: 160
        y: 311
        value: 0.5
    }
}

The advantage of this implementation is that you can modify the design and logic part independently. If you pass an object through setContextProperty it will be visible in all .qml files. With your previous approach you were going to have problems if you were going to have many .qml

Upvotes: 1

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