IOS在子線程中使用定時器，將定時器添加至RunLoop中

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

  //用NSObject的方法創建一個多線程
  [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種方式
  //此種方式創建的timer已經添加至runloop中
  

  // [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(timerAction) userInfo:nil repeats:YES];
  //保持線程爲活動狀態，才能保證定時器執行
  // [[NSRunLoop currentRunLoop] run];//已經將nstimer添加到NSRunloop中了

  //第2種方式
  //此種方式創建的timer沒有添加至runloop中
  

  NSTimer *timer = [NSTimer timerWithTimeInterval:1.0f target:self selector:@selector(timerAction) userInfo:nil repeats:YES];
  //將定時器添加到runloop中
  [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
  [[NSRunLoop currentRunLoop] run];
  NSLog(@”多線程結束”);
  }
  [pool release];
  }

• (void)timerAction
  {
  //定時器也是在子線程中執行的
  if (![NSThread isMainThread]) {
  NSLog(@”定時器”);
  }
  }