iphone - 每 10 分钟发送一次数据

Question

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    




// Override point for customization after application launch.

locmanager = [[CLLocationManager alloc] init]; 
[locmanager setDelegate:self]; 
[locmanager setDesiredAccuracy:kCLLocationAccuracyHundredMeters];
//[locmanager setDistanceFilter:10];
updateTimer = [NSTimer timerWithTimeInterval:600 target:self selector:@selector(startUpdating) userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop] addTimer:updateTimer forMode:NSDefaultRunLoopMode];

[window makeKeyAndVisible];

return YES;
}

 -(void)startUpdating
{
[locmanager startUpdatingLocation];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation 
{ 
       if (newLocation.horizontalAccuracy < 0) return;


  CLLocationCoordinate2D loc = [newLocation coordinate];
 currentdate=[[NSDate date]timeIntervalSince1970];
   latitude = [NSString stringWithFormat: @"%f", loc.latitude];
 longitude= [NSString stringWithFormat: @"%f", loc.longitude];
//Call to webservice to send data
}

我想每 10 分钟向网络服务发送一次坐标。尝试过这样做，但这不起作用。我的应用程序已注册以在后台获取位置更新。请建议我需要对此程序进行的更改。

Answer 1

我已经完成了类似的操作，使用 NSUserDefaults 记录上次发送到服务器的日期时间，并使用 NSTimeInterval 比较更新位置的日期戳和该值。我用的是 30 秒，但你可以向上调整。这有点麻烦，但它可以在后台运行等情况下使用。

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation   *)newLocation
       fromLocation:(CLLocation *)oldLocation
}

    updatedLocation = [newLocation retain];
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    NSDate *myDate = (NSDate *)[prefs objectForKey:@"myDateKey"];

    NSDate *lastDate = (NSDate *)newLocation.timestamp;
    NSTimeInterval theDiff = [lastDate timeIntervalSinceDate:myDate];

    if (theDiff > 30.0f || myDate == nil){
             //do your webservices stuff here
            NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
            [prefs setObject:lastDate forKey:@"myDateKey"];
            [prefs synchronize];

    }