pyqt5 qml 信号槽连接

Question

import QtQuick 2.2
import QtQuick.Controls 1.1
import QtQuick.Layouts 1.1

ApplicationWindow{
    visible:true
    width:640
    height:480
    id:window
    title:asTr("editor")

    signal show(string text)



    TextArea{
        text:"hello"
        onTextChanged:show(text);
    }

}

import sys
from PyQt5.QtCore import QObject, QUrl, Qt
from PyQt5.QtWidgets import QApplication
from PyQt5.QtQml import QQmlApplicationEngine

def show(text):
    print(text)


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



  engine.load('main.qml')

  win = engine.rootObjects()[0]


  win.show()
  sys.exit(app.exec_())

代码如上，我想用python代码中的show方法和qml文件中的show信号连接起来，我该怎么做呢？

Answer 1

写在qml里，我用C++的代码作为例子，python的做法应该是类似的，首先把C++对象（或python对象）暴露给qml：
engine.rootContext()->setContextProperty("myContext", myContext);
myContext要继承QObject，然后在qml里connect，如:

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

    signal show(string text) 
    Component.onCompleted: {
        show.connect(myContext.print);
    }
    ...
}