如何更新 Pyside2 GUI 上的进度条？

Question

我一直在尝试更新我的 GUI 上的进度条，但我不知道该怎么做......我提供的代码显示了进度更新 - 我只需要该值来更新我的 GUI 上的进度条也。 这是来自 Qt Creator 的 QML 文件。

主文件

import os
import sys
import time

from PySide2.QtGui import QGuiApplication
from PySide2.QtQml import QQmlApplicationEngine, qmlRegisterType
from PySide2.QtCore import QObject, Slot, Signal, QTimer, QUrl, QThread
from pathlib import Path

from multiprocessing.pool import ThreadPool

class MainWindow(QObject):
    def __init__(self):
        QObject.__init__(self)

    @Slot()
    def thread_progress(self):
        print("Worker")
        self.worker = Worker()
        self.thread = QThread()
        self.worker.moveToThread(self.thread)
        self.thread.start()
        self.worker.run()
        

class Worker(QObject):
    progress_value = Signal(float)

    @Slot()
    def run(self):
        self.progress = 0
        self.total = 100
        for i in range(0, self.total):
            self.update_progress()

    def update_progress(self):
        print(f"{self.progress} / {self.total}")
        self.progress += 1
        self.progress_value.emit(self.progress)
        time.sleep(1)

if __name__ == "__main__":
    app = QGuiApplication(sys.argv)
    engine = QQmlApplicationEngine()

    # Get Context
    main = MainWindow()
    engine.rootContext().setContextProperty("backend", main)
    # Set App Extra Info
    app.setOrganizationName("zardoss")
    app.setOrganizationDomain("N/A")

    engine.load(os.fspath(Path(__file__).resolve().parent / "main.qml"))
    if not engine.rootObjects():
        sys.exit(-1)
    sys.exit(app.exec_())

main.py 文件与 main.qml 文件连接。 GUI 有一个按钮、进度条和一个文本输入元素。 我只关心按下生成按钮后进度条会填满。 按下生成按钮后，您可以从控制台看到 1-100 的值正在填充，但它没有填充进度条，因为我不确定如何填充。

main.qml

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.15
import QtGraphicalEffects 1.15
import QtQuick.Shapes 1.15

Window {
    id: mainWindow
    width: 750
    height: 500
    visible: true
    color: "#00000000"

    // Remove title bar
    flags: Qt.Window | Qt.FramelessWindowHint

    // Properties
    property int windowStatus: 0
    property int windowMargin: 10

    title: qsTr("Progress Bar")
    Rectangle {
        id: bg
        color: "#2c313c"
        border.color: "#f12c313c"
        border.width: 1
        anchors.left: parent.left
        anchors.right: parent.right
        anchors.top: parent.top
        anchors.bottom: parent.bottom
        anchors.rightMargin: windowMargin
        anchors.leftMargin: windowMargin
        anchors.bottomMargin: windowMargin
        anchors.topMargin: windowMargin
        z:1

        Rectangle {
            id: appContainer
            height: 480
            color: "#00000000"
            anchors.left: parent.left
            anchors.right: parent.right
            anchors.top: parent.top
            anchors.bottom: parent.bottom
            anchors.rightMargin: 1
            anchors.leftMargin: 1
            anchors.bottomMargin: 1
            anchors.topMargin: 1

            Rectangle {
                id: content
                color: "#00000000"
                anchors.left: parent.left
                anchors.right: parent.right
                anchors.top: topBar.bottom
                anchors.bottom: parent.bottom
                anchors.topMargin: 0

                Button {
                    id: btnGenerate
                    x: 265
                    y: 44
                    width: 200
                    height: 50
                    text: "Generate"
                    anchors.verticalCenter: parent.verticalCenter
                    anchors.right: parent.right
                    anchors.horizontalCenterOffset: 0
                    anchors.horizontalCenter: parent.horizontalCenter
                    anchors.verticalCenterOffset: 165
//                    colorPressed: "#1e5425"
//                    colorMouseOver: "#42b852"
                    font.pointSize: 14
                    display: AbstractButton.TextBesideIcon
                    font.bold: false
//                    colorDefault: "#328a3f"
                    anchors.rightMargin: 250
                    onPressed: {
                        // backend.generate()
                        backend.thread_progress()
                    }
                }

                ProgressBar{
                    id: progressBar
                    x: 239
                    y: 64
                    visible: true
                    width: 661
                    height: 250
//                    text: "%"
                    anchors.verticalCenter: parent.verticalCenter
                    value: 0
                    //bgColor: "#00000/*000"
                    //dropShadowColor: "#20000000"
                    //samples: 16
                    anchors.verticalCenterOffset: -15
                    anchors.horizontalCenter: parent.horizontalCenter
                    
                }
            }
        }
    }
    DropShadow{
        anchors.fill: bg
        horizontalOffset: 0
        verticalOffset: 0
        radius: 10
        samples: 16
        color: "#80000000"
        source:bg
        z: 0
    }

    Connections{
        target: backend

        function onLinkValid(valid)  {
            if(valid === true)    {
                textField.textColor = "#00FF00"
            } else {
                textField.textColor = "#FF00FF"
            }
        }
    }
}

Answer 1

您的问题是具有进度值的信号未连接到 GUI 的任何元素。

在这种情况下，必须在与 ProgressBar 连接的 QML 暴露的 class 中创建一个信号，并且该信号必须从 Worker 的信号中接收信息。 另一方面，您不应直接调用“run()”方法，因为它将在调用它的线程中执行，在您的情况下是主线程，因此它将阻塞 GUI，而您必须调用它间接地用信号或使用QTimer。

import os
import sys
import time
from pathlib import Path

from PySide2.QtGui import QGuiApplication
from PySide2.QtQml import QQmlApplicationEngine
from PySide2.QtCore import QObject, Slot, Signal, QTimer, QUrl, QThread


class Backend(QObject):
    progress_changed = Signal(float, name="progressChanged")

    def __init__(self, parent=None):
        super().__init__(parent)

        self.worker = Worker()
        self.worker.progress_changed.connect(self.progress_changed)
        self.worker_thread = QThread()
        self.worker.moveToThread(self.worker_thread)
        self.worker_thread.start()

    @Slot()
    def start_worker(self):
        QTimer.singleShot(0, self.worker.run)


class Worker(QObject):
    progress_changed = Signal(float)

    @Slot()
    def run(self):
        self.progress = 0
        self.total = 100
        for i in range(0, self.total):
            self.update_progress()

    def update_progress(self):
        print(f"{self.progress} / {self.total}")
        self.progress += 1
        self.progress_changed.emit(self.progress)
        time.sleep(1)


if __name__ == "__main__":
    app = QGuiApplication(sys.argv)
    engine = QQmlApplicationEngine()

    backend = Backend()
    engine.rootContext().setContextProperty("backend", backend)
 
    engine.load(os.fspath(Path(__file__).resolve().parent / "main.qml"))
    if not engine.rootObjects():
        sys.exit(-1)
    ret = app.exec_()
    # backend.worker_thread.quit()
    # backend.worker_thread.wait()
    sys.exit(ret)

import QtQuick 2.15
import QtQuick.Controls 2.15
import QtQuick.Window 2.15

Window {
    id: mainWindow

    width: 750
    height: 500
    visible: true
    color: "#00000000"
    title: qsTr("Progress Bar")

    Row {
        spacing: 10
        anchors.centerIn: parent

        Button {
            id: btnGenerate

            text: "start"
            onClicked: backend.start_worker()
        }

        ProgressBar {
            id: progressBar
            from: 0
            to: 100.0
        }

    }

    Connections {
        target: backend

        function onProgressChanged(progress) {
            progressBar.value = progress;
        }

    }

}