python - 如何将父级发送到新的 ApplicationWindow

Question

我想恢复主控“main.qml”的位置和大小。但我不知道如何声明新窗口的父窗口。如果我直接从 javascript 中的窗口 main.qml 打开窗口，我没有问题，但通过 python 我不知道如何打开。

我想我必须使用“self.win”，但如何声明它？

感谢您的回复。

测试.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from PyQt5.QtGui import QGuiApplication
from PyQt5.QtQml import QQmlApplicationEngine
from PyQt5.QtCore import QObject, pyqtSignal, pyqtSlot
import sys

class Main2(QObject):

    def __init__(self, engine, what_send_for_send_the_parent):
        QObject.__init__(self)

        """ 
        How can I say to the new windows who is the parent  ?
        """
        context = engine.rootContext()
        context.setContextProperty("py_Page2", self)
        engine.load('test2.qml')
        self.win = engine.rootObjects()[0]  

class Main(QObject):

    def __init__(self, engine):
        QObject.__init__(self)

        self.context = engine.rootContext()
        self.property = self.context.setContextProperty("py_Page", self)
        self.load = engine.load('test.qml')
        self.win = engine.rootObjects()[0]  

        print("Context", self.context)  # <PyQt5.QtQml.QQmlContext object at 0xb65e6f30>
        print("Property", self.property)# None
        print("Load", self.property)    # None
        print("Win", self.win)          # <PyQt5.QtGui.QWindow object at 0xb65e6f80>

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

    main = Main(engine) 
    main2 = Main2(engine, "???")

    engine.quit.connect(app.quit)
    sys.exit(app.exec_())

测试.qml

import QtQuick 2.5
import QtQuick.Controls 1.4

ApplicationWindow {
    id: "main"
    visible: true
    width: 200; height: 240;    
    Text {text: qsTr("main")} 
}

test2.qml

import QtQuick 2.5
import QtQuick.Controls 1.4

ApplicationWindow {
    id: "main2"
    visible: true
    width: 200; height: 240;
    x: main.x
    y: main.y
    Text {text: qsTr("main2")}
}

<小时/>

我想我已经找到了:

class Main2(QObject):

    def __init__(self, engine, master):
        QObject.__init__(self)
        context = engine.rootContext()
        context.setContextProperty("main_x", master.win.property("x"))
        context.setContextProperty("main_y", master.win.property("y"))
        engine.load('test2.qml')

...
    main = Main(engine) 
    main2 = Main2(engine, main)
...

并在qml文件中

ApplicationWindow {
    id: "main2"
    visible: true
    width: 200; height: 240;
    x: main_x + 20
    y: main_y + 120
    Text {text: qsTr("main2")}
}

我可以这样恢复值。它是否正确？有没有更传统的方法？

Answer 1

虽然该解决方案在这种情况下有效，但在更实际的情况下可能会失败，在这种情况下，每个 QML 可以加载许多组件，因为 QML 加载是异步的，但您的过程是同步的。

解决方案是创建一个 QObject 并使用 setContextProperty() 将其导出到 QML，以便可以从通过 QQmlApplicationEngine 加载的所有 QML 访问它。该 QObject 必须具有一个属性，该属性是您想要获取的属性的镜像。

ma​​in.py

from PyQt5.QtCore import pyqtProperty, pyqtSignal, QObject, QPoint, QUrl
from PyQt5.QtGui import QGuiApplication
from PyQt5.QtQml import QQmlApplicationEngine


class Manager(QObject):
    positionChanged = pyqtSignal()

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

    @pyqtProperty(QPoint, notify=positionChanged)
    def position(self):
        return self._position

    @position.setter
    def position(self, p):
        if self._position != p:
            self._position = p
            self.positionChanged.emit()


if __name__ == "__main__":
    import os
    import sys

    app = QGuiApplication(sys.argv)

    engine = QQmlApplicationEngine()
    manager = Manager()
    engine.rootContext().setContextProperty("manager", manager)

    current_dir = os.path.dirname(os.path.realpath(__file__))

    engine.load(QUrl.fromLocalFile(os.path.join("test.qml")))
    engine.load(QUrl.fromLocalFile(os.path.join("test2.qml")))

    engine.quit.connect(app.quit)
    sys.exit(app.exec_())

测试.qml

import QtQuick 2.5
import QtQuick.Controls 1.4

ApplicationWindow {
    id: root
    visible: true
    width: 200
    height: 240
    Text {
        text: qsTr("main")
    }
    Component.onCompleted: manager.position = Qt.point(root.x, root.y)
}

test2.qml

import QtQuick 2.5
import QtQuick.Controls 1.4

ApplicationWindow {
    visible: true
    width: 200
    height: 240
    x: manager.position.x
    y: manager.position.x
    Text {
        text: qsTr("main2")
    }
}