延时函数和Timer的使用

//延时函数：[NSThread sleepForTimeInterval:5.0]； //暂停5s.//Timer的使用：NSTimer *connectionTimer;  //timer对象//实例化timerself.connectionTimer=[NSTimerscheduledTimerWithTimeInterval:1.5 target:selfselector:@selector(timerFired:) userInfo:nil repeats:NO];[[NSRunLoop currentRunLoop]addTimer:self.connectionTimer forMode:NSDefaultRunLoopMode];//用timer作为延时的一种方法   do{[[NSRunLoopcurrentRunLoop]runUntilDate:[NSDatedateWithTimeIntervalSinceNow:1.0]];}while(!done); //timer调用函数-(void)timerFired:(NSTimer *)timer{done =YES;}