// 只执行最后一次
[
NSObject
cancelPreviousPerformRequestsWithTarget
:
self
];
[
self
performSelector
:
@selector
(realClick)
withObject
:
nil
afterDelay
:
5
];
// 只执行一次
static
dispatch_once_t
onceToken;
dispatch_once
(&onceToken, ^{
NSLog
(
@"once times"
);
});