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Python QML文本不';除非调整窗口大小,否则无法更新_Python_Python 3.x_Qt_Qml_Qtquick2 - Fatal编程技术网

Python QML文本不';除非调整窗口大小,否则无法更新

Python QML文本不';除非调整窗口大小,否则无法更新,python,python-3.x,qt,qml,qtquick2,Python,Python 3.x,Qt,Qml,Qtquick2,我有以下Python代码 import sys import os import threading from time import sleep from PySide2.QtCore import QObject from PySide2.QtGui import QGuiApplication from PySide2.QtQml import QQmlApplicationEngine def add_text(log_text): i = 1 while True

我有以下Python代码

import sys
import os
import threading
from time import sleep

from PySide2.QtCore import QObject
from PySide2.QtGui import QGuiApplication
from PySide2.QtQml import QQmlApplicationEngine


def add_text(log_text):
    i = 1
    while True:
        text = log_text.property("text")
        log_text.setProperty("text", text + "\n" + str(i))
        i += 1
        sleep(1)


app = QGuiApplication(sys.argv)
engine = QQmlApplicationEngine()
engine.load(os.path.join(os.path.dirname(__file__), "main.qml"))

root = engine.rootObjects()[0]
log_text = root.findChild(QObject, 'log_text')
x = threading.Thread(target=add_text, args=(log_text,))
x.start()

if not engine.rootObjects():
    sys.exit(-1)
sys.exit(app.exec_())
以及下面的QML文件

import QtQuick 2.13
import QtQuick.Window 2.13
import QtQuick.Layouts 1.15
import QtQuick.Controls 2.13


Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    RowLayout {
        id: main_row
        anchors.fill: parent
        spacing: 0

        Rectangle {
            id: log_background
            width: 250
            height: 480
            color: "#515151"
            Layout.fillHeight: true

            Text {
                id: log_text
                objectName: "log_text"
                color: "#ffffff"
                anchors.fill: parent
                font.pixelSize: 12
                verticalAlignment: Text.AlignBottom
            }
        }

        ColumnLayout {
            id: image_buttons_column
            width: 100
            height: 100
            spacing: 0

            Image {
                id: image
                width: 504
                height: 429
                source: "qrc:/qtquickplugin/images/template_image.png"
                Layout.fillHeight: true
                Layout.fillWidth: true
                cache: true
                smooth: true
                mirror: false
                mipmap: false
                autoTransform: false
                asynchronous: false
                fillMode: Image.PreserveAspectFit
            }

            RowLayout {
                id: buttons_row
                width: 100
                height: 100
                spacing: 0

                Button {
                    id: button_yes
                    objectName: "button_yes"
                    Layout.fillWidth: true
                    palette {
                        button: "#64e764"
                    }
                    font.pointSize: 16
                    text: "Yes"
                    signal pressed
                    onClicked: pressed()
                }
                Button {
                    id: button_maybe
                    objectName: "button_maybe"
                    Layout.fillWidth: true
                    palette {
                        button: "#ffff00"
                    }
                    font.pointSize: 16
                    text: "Maybe"
                    signal pressed
                    onClicked: pressed()
                }
                Button {
                    id: button_no
                    objectName: "button_no"
                    Layout.fillWidth: true
                    palette {
                        button: "#ff726f"
                    }
                    font.pointSize: 16
                    text: "No"
                    signal pressed
                    onClicked: pressed()
                }
            }
        }
    }
}

当我运行上面的python脚本时,文本会自我更新一次,显示数字1,然后停止。每当我调整窗口大小时,所有本应添加的数字都会突然显示出来。如何使文本区域在文本更改时而不是在窗口调整大小时自动更新?

您试图从主线程以外的线程操作Qt。这将不起作用,并可能导致崩溃。几乎所有GUI工具包都只能从主线程进行操作

在这种特殊情况下,我将在QML文件中使用QML
Timer
对象。它将在主线程上执行,并实现相同的目的。像这样:

            Text {
                id: log_text
                objectName: "log_text"
                color: "#ffffff"
                anchors.fill: parent
                font.pixelSize: 12
                verticalAlignment: Text.AlignBottom

                Timer {
                    interval: 1000
                    running: true
                    repeat: true

                    property int i: 1
                    onTriggered: {
                        log_text.text += `\n${i}`;
                        i += 1;
                    }
                }
            }


如果出于其他原因必须在单独的线程中完成此操作,则需要从该线程调用主线程上的处理程序,以通过信号实际操作Qt。Qt信号机制检测信号何时跨越线程,并在其事件队列上正确调度接收端的信号。

能否请您提供一个示例,说明如何使用QML计时器实现这一点,我在internet上找到的示例根本不起作用。好的,为您添加了一个计时器示例。这非常有效,谢谢!