RunLoop（基本操作）

-(void)runTimerInThread{    //NSAutoreleasePool,没的用    [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(doSth:) userInfo:self repeats:YES];        //1.以上方法自动把NSTimer添加到RunLoop里面        NSTimer* timer=[NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(doSth:) userInfo:self repeats:YES];        //2.以上方法不会自动NSTimer添加到RunLoop里面    [[NSRunLoop currentRunLoop]addTimer:timer forMode:NSDefaultRunLoopMode];    //要手动加入runLoop,额额,类方法就写入了 addTimer:timer forMode:NSDefaultRunLoopMode;            [[NSRunLoop currentRunLoop]run];    //这很重要,把定时器的线程加入运行回环runloop才会使线程处于活跃状态}

 [self performSelectorInBackground:@selector(runTimerInThread) withObject:nil];