self performSelector: withObject: afterDelay:
延迟事件再推出viewcontroller时要注意
//取消所有延迟事件
[NSObject cancelPreviousPerformRequestsWithTarget:self];
self performSelector: withObject: afterDelay:
延迟事件再推出viewcontroller时要注意
//取消所有延迟事件
[NSObject cancelPreviousPerformRequestsWithTarget:self];