ios NSNotificationCenter 消息的收发

发消息：

1 [[NSNotificationCenter defaultCenter] postNotificationName:@"WECHARTPAY"object:nil];

收消息初始化：

1 NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
2 [notificationCenter addObserver:self selector:@selector(handlePayFinished:) name:@"WECHARTPAY" object:nil] ;

收消息处理方法：

1 - (void)handlePayFinished:(NSNotification *)notification
2 {
3
4 }