ios - 在另一个 View Controller 中停止线程

Question

我对线程非常陌生，所以请多多指教。

在用户通过身份验证后的登录 View Controller 中，我启动一个线程以每 30 秒获取用户地理位置(只想在用户登录时执行此操作)，然后移动到应用程序的主视图 Controller 显示应用程序的主要信息。

当用户注销时，我想取消为每 30 秒收集一次地理位置而创建的线程。

我该怎么做？

我接近这个正确吗？如果没有，请提供代码示例和解释

非常感谢!!!

登录 View Controller

...
- (IBAction)loginButton:(id)sender {
    NSInteger success = 0;

    //Check to see if the username or password texfields are empty or email field is in wrong format
    if([self validFields]){
        //Try to login user
        success = [self loginUser];
    }
    //If successful, go to the MainView
    if (success) {
        //Start getting users Geolocation in a thread
        [NSThread detachNewThreadSelector:@selector(startGeolocation:) toTarget:self withObject:nil];

        //Go to Main view controller
        [self performSegueWithIdentifier:@"loginSuccessSegue" sender:self];
    }
    else
    {
        //Reset password text field
        self.passwordTextField.text = @"";
    }
}
...
//Thread to get Geolocation every 30 seconds
-(void)startGeolocation:(id)param{
    self.geoLocation = [[GeoLocation alloc] init];
    while(1)
    {
        //****************START GEOLOCATION*******************************//
        AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
        [appDelegate.databaseLock lock];
        NSLog(@"Geolocation:(%f,%f)", [self.geoLocation getLatitude], [self.geoLocation getLongitude]);
        sleep(30);
        [appDelegate.databaseLock unlock];
    }
}

主视图 Controller

...
//When the Logout Button in MenuView is pressed this method will be called
- (void)logoutButton{

    //Cancel the geolocation tread
    //????????????????????????????        

    //Log the user out
    [self logoutUser]
}
...

Answer 1

我建议为此使用 GCD。

dispatch_queue_t dq = dispatch_queue_create("bkgrndQueue", NULL);
dispatch_async(dq, ^{
  @autoreleasepool{
     while(SEMAPHORE_NAME){
        // do stuff in here
     }
   }
}

然后在你的另一个 View Controller 中

SEMAPHORE_NAME = NO;