- (BOOL)isOnLocation

{

    BOOL isOn = false;

    if (([CLLocationManager locationServicesEnabled]) && ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusAuthorized)) {

        NSLog(@"定位已经开启");

        isOn = true;

    } else {

        NSLog(@"定位未开启");

        isOn = false;

    }

    return isOn;

}

    if (![self isOnLocation]) {

        UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"警告" message:@"您的定位服务没有打开，请在设置中开启" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];

        [alertView show];

        //[[UIApplication sharedApplication] openURL:[NSURL URLWithString: @"prefs:root=LOCATION_SERVICES"]];

    }