我不會從 python 動態創建元素，我只是想訪問 qml 文件中已聲明的現有元素。我使用 findChild 來獲取 QObject 引用并連接到信號。這工作正常，但是當我嘗試更具體并獲取像 QComboBox 這樣的小部件（不是 QObject）時，我總是得到 None。我是否遺漏了一些東西或者 findChild 不適合與小部件一起使用？這是我的簡單 qml 代碼：Window { visible:true width:600 height:400 Button { id: clickMe objectName: "clickMe" x: 244 y: 263 text: qsTr("click me!") } ComboBox { id: comboBox objectName: "comboBox" x: 199 y: 157 width: 200 }}這是我的Python代碼：# qt importsfrom PyQt5.QtQml import QQmlApplicationEnginefrom PyQt5.QtWidgets import QApplication, QWidget, QInputDialog, QLineEdit, QMessageBoxfrom PyQt5.QtWidgets import QComboBox, QPushButtonfrom PyQt5 import QtWidgets, QtGuifrom PyQt5.QtGui import QIconfrom PyQt5.QtCore import QObjectapp = QApplication(sys.argv)engine = QQmlApplicationEngine()engine.load('main.qml')win = engine.rootObjects()[0]win.show()# this does work because it is QObject:clickMe = win.findChild(QObject, "clickMe")clickMe.clicked.connect(Foo)# this does not work, I get None so can't add items to the combobox:comboBox = win.findChild(QComboBox, "comboBox")comboBox.addItem("a")sys.exit(app.exec_())
1 回答
holdtom
TA貢獻1805條經驗 獲得超10個贊
首先，QML Item Combobox 不是 QtWidgets QComboBox，因此您不應該使用該類進行過濾，這就是您的嘗試失敗的原因。從 python（或 C++）訪問 QML 元素也是不好的做法，因為生命周期不受管理（例如，可以刪除并重新創建相同“id”的對象而不通知），相反，您必須創建允許交換信息的 QObject ，例如對于 QComboBox，您可以創建一個模型：
main.py
import os
import sys
# qt imports
from PyQt5.QtCore import pyqtProperty, pyqtSlot, QObject, QUrl
from PyQt5.QtGui import QGuiApplication, QStandardItem, QStandardItemModel
from PyQt5.QtQml import QQmlApplicationEngine
CURRENT_DIR = os.path.dirname(os.path.realpath(__file__))
class Manager(QObject):
def __init__(self, parent=None):
super().__init__(parent)
self._model = QStandardItemModel()
@pyqtProperty(QObject, constant=True)
def model(self):
return self._model
@pyqtSlot()
def foo(self):
print("clicked")
def main():
app = QGuiApplication(sys.argv)
manager = Manager()
engine = QQmlApplicationEngine()
engine.rootContext().setContextProperty("manager", manager)
filename = os.path.join(CURRENT_DIR, "main.qml")
engine.load(QUrl.fromLocalFile(filename))
item = QStandardItem("a")
manager.model.appendRow(item)
sys.exit(app.exec_())
if __name__ == "__main__":
main()
主.qml
import QtQuick.Window 2.15
import QtQuick.Controls 2.15
Window {
visible:true
width:600
height:400
Button {
id: clickMe
x: 244
y: 263
text: qsTr("click me!")
onClicked: manager.foo()
}
ComboBox {
id: comboBox
x: 199
y: 157
width: 200
model: manager.model
textRole: "display"
}
}
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