- (void)buttonClicked:(id)sender
{
  //这里是关键，点击按钮后先取消之前的操作，再进行需要进行的操作
  [[self class] cancelPreviousPerformRequestsWithTarget:self selector:@selector(buttonClicked:) object:sender];
  [self performSelector:@selector(buttonClicked: )withObject:sender afterDelay:0.2f];
}

-(void)buttonClicked:(id)sender{
  self.button.enabled = NO;
  [self performSelector:@selector(changeButtonStatus) withObject:nil afterDelay:1.0f];//防止用户重复点击
}

-(void)changeButtonStatus{
  self.button.enabled = YES;
}

- (void) timeEnough
{
 
UIButton *btn=(UIButton*)[self.view viewWithTag:33];
 
btn.selected=NO; 
[timer invalidate];
 
timer=nil; 
}

 - (void) btnDone:(UIButton*)btn
 {
 if(btn.selected) return;
 btn.selected=YES;
 [self performSelector:@selector(timeEnough) withObject:nil afterDelay:3.0]; //使用延时进行限制。
//to do something.
｝