1 1 #include <QtGui/QApplication>
  2   2 #include <QCoreApplication>
  3   3 #include <QEvent>
  4   4 #include <QObject>
  5   5 #include <QDebug>
  6   6 
  7   7 //声明、定义、注册自定义事件类型，事件ID为自定义事件ID起点QEvent::User +100=1100
  8   8 static const QEvent::Type MyEventType = (QEvent::Type)QEvent::registerEventType(QEvent::User+100);
  9   9 
 10  10 //长官
 11  11 class MyEvent: public QEvent
 12  12 {
 13  13 public:
 14  14     MyEvent(Type myeventtype):QEvent(myeventtype){}
 15  15 };
 16  16 
 17  17 //信使
 18  18 class MySender: public QCoreApplication
 19  19 {
 20  20 public:
 21  21     MySender(int argc,char *argv[]):QCoreApplication(argc,argv){}
 22  22 
 23  23 public:
 24  24     bool notify(QObject *receiver, QEvent *event);
 25  25 
 26  26 };
 27  27 
 28  28 bool MySender::notify(QObject *receiver, QEvent *event)
 29  29 {
 30  30     if(event->type() == MyEventType)
 31  31     {
 32  32         qDebug()<<"MyEventType is coming!";
 33  33         //return true;
 34  34         /*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，
 35  35         随便搞它，搞完了还得给QCoreApplication::notify向下传递，除非在mySender.notify
 36  36         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
 37  37         mySender.notify的return true后，事件传递被人为的在半截终止了
 38  38         （见Qt事件处理的五个层次http://blog.csdn.net/michealtx/article/details/6865891 ）
 39  39         ，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
 40  40         的myEventHandler了。所以在主函数中执行完mySender.sendEvent把myEvent
 41  41         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
 42  42         问题http://topic.csdn.net/u/20111012/19/78036d16-c163-40f9-a05c-3b7d6f4e9043.html
 43  43         出现的原因。感谢1+1=2大牛！非常感谢！
 44  44         */
 45  45     }
 46  46     return QCoreApplication::notify(receiver,event);
 47  47 }
 48  48 
 49  49 //军队
 50  50 class MyArmy: public QObject
 51  51 {
 52  52 public:
 53  53     void MyEventHandler(QEvent *event);//自定义事件函数
 54  54     bool event(QEvent *event);
 55  55 };
 56  56 
 57  57 void MyArmy::MyEventHandler(QEvent *event)
 58  58 {
 59  59     qDebug()<<"The event is being handled!";
 60  60     event->accept();
 61  61 }
 62  62 
 63  63 bool MyArmy::event(QEvent *event)
 64  64 {
 65  65     if(event->type() == MyEventType)
 66  66     {
 67  67         qDebug()<<"event() is dispathing MyEvent";
 68  68         MyEventHandler(event);//调用事件处理函数
 69  69         if((MyEvent*)event->isAccepted())
 70  70         {
 71  71             qDebug()<<"The event has been handled!";
 72  72             return true;
 73  73         }
 74  74     }
 75  75     return QObject::event(event);
 76  76 }
 77  77 
 78  78 //监控者
 79  79 class MyWatcher: public QObject
 80  80 {
 81  81 public:
 82  82     bool eventFilter(QObject *watched, QEvent *event);
 83  83 };
 84  84 
 85  85 bool MyWatcher::eventFilter(QObject *watched, QEvent *event)
 86  86 {
 87  87     if(event->type() == MyEventType)
 88  88     {
 89  89         qDebug()<<"I don‘t wanna filter MyEventType";
 90  90         return false;
 91  91     }
 92  92     return QObject::eventFilter(watched,event);
 93  93 }
 94  94 
 95  95 
 96  96 int main(int argc, char *argv[])
 97  97 {
 98  98     //QCoreApplication a(argc, argv);
 99  99     MySender mySender(argc,argv);
100 100 
101 101     MyArmy myArmy;
102 102     MyWatcher myWatcher;
103 103     myArmy.installEventFilter(&myWatcher);//安装事件过滤器
104 104 
105 105     MyEvent myEvent(MyEventType);
106 106     mySender.sendEvent(&myArmy,&myEvent);
107 107     return mySender.exec();
108 108 }