IOS在子线程中使用定时器，将定时器添加至RunLoop中

• (BOOL)application:(UIApplication )application didFinishLaunchingWithOptions:(NSDictionary )launchOptions
  {
  self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

  //用NSObject的方法创建一个多线程
  [self performSelectorInBackground:@selector(multiThread) withObject:nil];

  self.window.backgroundColor = [UIColor whiteColor];
  [self.window makeKeyAndVisible];
  return YES;
  }

• (void)multiThread
  {
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  if (![NSThread isMainThread]) {

  // 第1种方式//此种方式创建的timer已经添加至runloop中

  // [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(timerAction) userInfo:nil repeats:YES];
  //保持线程为活动状态，才能保证定时器执行
  // [[NSRunLoop currentRunLoop] run];//已经将nstimer添加到NSRunloop中了

  //第2种方式//此种方式创建的timer没有添加至runloop中

  NSTimer *timer = [NSTimer timerWithTimeInterval:1.0f target:self selector:@selector(timerAction) userInfo:nil repeats:YES];
  //将定时器添加到runloop中
  [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
  [[NSRunLoop currentRunLoop] run];
  NSLog(@”多线程结束”);
  }
  [pool release];
  }

• (void)timerAction
  {
  //定时器也是在子线程中执行的
  if (![NSThread isMainThread]) {
  NSLog(@”定时器”);
  }
  }