Qt for Python使用Qt中的Properties

PySide2提供了一个Property函数，它允许声明同时表现为Qt和Python属性的属性，并将其setter和getter定义为Python函数。

下面给出了一个简单的示例，说明如何从Python定义和访问Qt属性：

from PySide2.QtCore import QObject,Property

class StudentMsg(QObject):
	"""docstring for StudentMsg"""
	def __init__(self):
		QObject.__init__(self)

	def readMsg(self):
		return self.msgval

	def setMsg(self,msg):
		self.msgval = msg

	MSG = Property(str,readMsg,setMsg)

student = StudentMsg()
student.MSG = "aaa"

print(student.MSG)

如果要在QML表达式中调用对象的属性，则QML要求属性为在变化时有信号通知。所以需要在上面示例的基础上增加一个信号：

from PySide2.QtCore import QObject,Property,Signal

class StudentMsg(QObject):
	"""docstring for StudentMsg"""
	def __init__(self):
		QObject.__init__(self)

	msg_changed = Signal(str)

	def readMsg(self):
		return self.msgval

	def setMsg(self,msg):
		self.msgval = msg
		self.msg_changed.emit(msg)


	MSG = Property(str,readMsg,setMsg,notify = msg_changed)

student = StudentMsg()
student.MSG = "aaa"

print(student.MSG)