Question

我想问一个关于核心位置和核心数据的问题。我看了一些问题，但无法做到这一点.. 我有一个应用程序，它存储UITableView中的一些文本字段，照片，日期和时间数据与核心数据，我存储了一切（照片，文本，日期等）现在尝试存储我无法做的位置数据。

这是我的一些代码。

    #pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];

    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    [locationManager startUpdatingLocation];

    NSDateFormatter *myFormatter = [[NSDateFormatter alloc] init];
    [myFormatter setDateFormat:@"MM-dd-yyyy HH:mm"];
    [myFormatter setTimeZone:[NSTimeZone systemTimeZone]];

    todaysDate = [myFormatter stringFromDate:[NSDate date]];
    myDateLabel.text = todaysDate;

    UIView *patternBg = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
    patternBg.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"background01.png"]];
    self.tableView.backgroundView = patternBg;

    // If we are editing an existing picture, then put the details from Core Data into the text fields for displaying

    if (currentPicture)
    {
        [companyNameField setText:[currentPicture companyName]];
        [myDateLabel setText:[currentPicture currentDate]];

        if ([currentPicture photo])
            [imageField setImage:[UIImage imageWithData:[currentPicture photo]]];
    }
}

在saveButton中

    - (IBAction)editSaveButtonPressed:(id)sender
{
    // For both new and existing pictures, fill in the details from the form
    [self.currentPicture setCompanyName:[companyNameField text]];
    [self.currentPicture setCurrentDate:[myDateLabel text]];
    [self.currentPicture setCurrentTime:[myTimeLabel text]];
    [self.currentPicture setLatitudeData:[_latitudeLabel text]];
    [self.currentPicture setLongtidueData:[_longtitudeLabel text]];

}

和最后一个，我的locationManager的方法..

    - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"didUpdateToLocation: %@", newLocation);
    CLLocation *currentLocation = newLocation;

    if (currentLocation != nil) {
        _longtitudeLabel.text = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.longitude];
        _latitudeLabel.text = [NSString stringWithFormat:@"%.8f", currentLocation.coordinate.latitude];
         [self->locationManager stopUpdatingLocation];
    }


}

我试过“[locationmanager stopUpdatingLocation];”很多次，但是当我进入应用程序时，代码开始计算纬度和经度数据，我只想将该数据取出1次，并存储..

谢谢！

Answer 1

如果调用stopUpdatingLocation并未停止位置更新，则很可能self->locationManager为零。这意味着你并没有真正打电话。

很难确定为什么会发生这种情况，除了你的代码似乎使用@property声明隐含的任何语义来强调不。只需在location中分配viewDidLoad即可避免任何声明，并使用self->locationManager查找经理。假设location是一个属性，您应该将其分配给self.locationManager，并在查找时使用它。

Answer 2

一些事情：

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    NSTimeInterval locationAge = -[newLocation.timestamp timeIntervalSinceNow];
    if (locationAge > 5) return;  // ignore cached location, we want current loc

    if (newLocation.horizontalAccuracy <= 0) return;  // ignore invalid

    // wait for GPS accuracy (will be < 400)
    if (newLocation.horizontalAccuracy < 400) {
        _longtitudeLabel.text = [NSString stringWithFormat:@"%.8f", newLocation.coordinate.longitude];
        _latitudeLabel.text = [NSString stringWithFormat:@"%.8f", newLocation.coordinate.latitude];
         [manager stopUpdatingLocation];
    }    
}

Answer 3

在你的didUpdateToLocation中执行此代码

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

NSTimeInterval locationAge = - [newLocation.timestamp timeIntervalSinceNow]; if（locationAge＆gt; 5）返回;

//忽略缓存位置，我们想要当前的位置
if（newLocation.horizontalAccuracy＆lt; = 0）返回; //忽略无效

//等待GPS准确度（将<400） if（newLocation.horizontalAccuracy＆lt; 400）{     _longtitudeLabel.text = [NSString stringWithFormat：@“％。8f”，newLocation.coordinate.longitude];     _latitudeLabel.text = [NSString stringWithFormat：@“％。8f”，newLocation.coordinate.latitude];      [经理stopUpdatingLocation];

//将nil分配给locationManager对象并委托
     locationManager.delegate = nil;
     locationManager = nil;

}

}

感谢。

将CLLocation（纬度，经度数据）存储到Core Data中

3 个答案: