3.自定义事件原理

Author: 625781186

partner_625781186/3.机制讲解/3.1 自定义事件/3.1.1 原理/myEvent.py

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+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+'''
+@resource:http://blog.csdn.net/zzwdkxx/article/details/39338429
+@description: 自定义QEvent事件,上面网址为C++版本原理解释,此篇为python改编
+@Created on 2018年3月22日
+@email: 625781186@qq.com
+'''
+
+from PyQt5 import QtGui, QtWidgets, QtCore
+from PyQt5.QtCore import *
+from PyQt5.QtGui import *
+from PyQt5.QtWidgets import *
+
+
+MyEventType = QEvent.registerEventType(QEvent.User+100)
+
+#//长官
+
+class MyEvent (QEvent):
+    def __init__(self, *args, **kwargs):
+        super(MyEvent, self).__init__(*args, **kwargs)
+        print(MyEventType)
+        def QEvent(self,MyEventType):
+            pass
+
+#//信使
+
+class MySender(QCoreApplication):
+
+    def __init__(self, *args, **kwargs):
+        super(MySender, self).__init__(*args, **kwargs)
+    def notify(self, receiver,  event):
+
+        if(event.type() == MyEventType):
+        
+            print("MyEventType is coming!")
+            # //return true;
+            # /*这里不能return true,因为重写notify就是在事件被向下传递之前截住它，
+            # 随便搞它，搞完了还得给QCoreApplication::notify向下传递，除非在mySender.notify
+            # 实现了事件向下传递的那一套。直接返回的话myArmy就收不到这个事件，因为执行完这个
+            # mySender.notify的return true后，事件传递被人为的在半截终止了
+            # （见Qt事件处理的五个层次http:#//blog.csdn.net/michealtx/article/details/6865891 ）
+            # ，下面的myArmy的安装的过滤器和它自己的event都不会收到这个事件，更甭提最后干活
+            # 的myEventHandler了。所以在主函数中执行完mySender.sendEvent把myEvent
+            # 交给mySender.notify这个败家子儿后，就执行mySender.exec进入其它事件的循环了。这就是
+            # 问题http:#//topic.csdn.net/u/20111012/19/78036d16-c163-40f9-a05c-3b7d6f4e9043.html
+            # 出现的原因。感谢1+1=2大牛！非常感谢！
+            # */
+        
+        return QCoreApplication.notify(self,receiver, event)
+
+#//军队
+
+class MyArmy (QWidget):
+
+    def MyEventHandler(self,event):
+
+        print("The event is being handled!")
+        event.accept()
+
+    def event(self, event):
+
+        if(event.type() == MyEventType):
+        
+            print("event() is dispathing MyEvent")
+            self.MyEventHandler(event)  # //调用事件处理函数
+            if(event.isAccepted()):
+            
+                print("The event has been handled!")
+                return True
+        return QObject. event(self,event)
+
+
+#//监控者
+
+class MyWatcher (QObject):
+
+    def eventFilter(self,watched, event):
+
+        if(event.type() == MyEventType):
+        
+            print("I don't wanna filter MyEventType")
+            return False
+        
+        return QObject.eventFilter(self,watched, event)
+
+
+if __name__ == "__main__":
+    import sys
+    #//QCoreApplication a(argc, argv);
+    app = QtWidgets.QApplication(sys.argv)
+    mySender = MySender(sys.argv)
+
+    myArmy=MyArmy ()
+    myWatcher=MyWatcher ()
+    myArmy.installEventFilter(myWatcher)  # //安装事件过滤器
+
+    myEvent=MyEvent (MyEventType)
+    mySender.sendEvent( myArmy,  myEvent)
+    mySender.exec()