例外:'无效区域<中心:+ inf,+ 0.0000000000范围:+1.00000000,+ 0.50000000>'尝试显示地图时

Question

当我尝试显示地图时,我得到了这个例外:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Invalid Region <center:+inf, +0.00000000 span:+1.00000000, +0.50000000>'

我的相关代码是这样的:

-(void)viewWillAppear:(BOOL)animated
{   
    [mapView removeAnnotations:mapView.annotations];

    // locationManager update as location
    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self; 
    locationManager.desiredAccuracy = kCLLocationAccuracyBest; 
    locationManager.distanceFilter = kCLDistanceFilterNone; 
    [locationManager startUpdatingLocation];
    CLLocation *location = [locationManager location];
    //Configure the new event with information from the location
    CLLocationCoordinate2D coordinate = [location coordinate];

    latitudeOfUserLocation=coordinate.latitude;
    longitudeOfUserLocation=coordinate.longitude;


    location2D = (CLLocationCoordinate2D){ .latitude = latitudeOfUserLocation, .longitude = longitudeOfUserLocation };
    MyLocation *annotation=[[[MyLocation alloc]initWithName:@"You are here" distanceVersLaStation:@"" coordinate:location2D]autorelease];
    annotation.pinColor = MKPinAnnotationColorRed;  
    [mapView addAnnotation:annotation];

    MKCoordinateSpan span={latitudeDelta:1,longitudeDelta:0.5};
    MKCoordinateRegion region={location2D,span};
    [mapView setRegion:region];

}

我无法弄清楚如何解决这个问题,提前thx :)

编辑:

嗨再次,我尝试按照你说的做,异常得到解决,但是,当我尝试在控制台中显示用户的经度/纬度我什么都没有,这是我的代码是非常正确的:

    -(void)viewWillAppear:(BOOL)animated
    {  

        [mapView removeAnnotations:mapView.annotations];

        // locationManager update as location
        locationManager = [[CLLocationManager alloc] init];
        locationManager.delegate = self; 
        locationManager.desiredAccuracy = kCLLocationAccuracyBest; 
        locationManager.distanceFilter = kCLDistanceFilterNone; 
        [locationManager startUpdatingLocation];
        NSURL *url=[NSURL         URLWithString:@"http://ipho.franceteam.org/ad_V1/stations/"];
    ASIFormDataRequest * request=[ASIFormDataRequest requestWithURL:url];
[request setPostValue:[NSNumber numberWithFloat:longitudeOfUserLocation] forKey:@"longitude"];
    [request setDelegate:self];
    [request startAsynchronous];
    MBProgressHUD *hud=[MBProgressHUD showHUDAddedTo:self.view animated:YES];
    hud.labelText=@"Recherche en cours..";// this never stop loading

    }

-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    CLLocation *location = [locationManager location];
    //Configure the new event with information from the location
    CLLocationCoordinate2D coordinate = [location coordinate];
    latitudeOfUserLocation=coordinate.latitude;
    longitudeOfUserLocation=coordinate.longitude;
    NSLog(@"your latitude :%f",latitudeOfUserLocation);//here nothing is shown
    NSLog(@"your longitude :%f",longitudeOfUserLocation);// and here too
    location2D = (CLLocationCoordinate2D){ .latitude = latitudeOfUserLocation, .longitude = longitudeOfUserLocation };
    MyLocation *annotation=[[[MyLocation alloc]initWithName:@"Vous êtes ici" distanceVersLaStation:@"" coordinate:location2D]autorelease];
    annotation.pinColor = MKPinAnnotationColorRed;  //or red or whatever
    [mapView addAnnotation:annotation];
    //
    MKCoordinateSpan span={latitudeDelta:1,longitudeDelta:0.5};
    MKCoordinateRegion region={location2D,span};
    [mapView setRegion:region];

}//End function

即使我在模拟器上工作,我应该在控制台上得到一些东西吗？

编辑: 嗨再次,我有机会在iPhone(设备)上测试我的代码,我注意到,当我尝试搜索时,应用程序已经过度追踪我的位置并找到符合我搜索的站点(紫色注释) )但是,地图不会显示,搜索进度仍在加载,永不停止.

hud.labelText=@"Recherche en cours..";// this never stop loading

这是一个可以更好地解释的截图:

Answer 1

在某些情况下(当应用程序从后台变为活动状态时)会触发didUpdateUserLocation方法,但不会更新位置.在这些情况下,没有有效的区域,并且setRegion:方法可以抛出异常.愚蠢的,一个简单的解决方案是在设置之前检查其区域是否有效:

 if(region.center.longitude == -180.00000000){
    NSLog(@"Invalid region!");
}else{
    [aMapView setRegion:region animated:YES];
}

Answer 2

"无效区域"异常是通过,因为您设置为mapView的区域无效.据我所知,有两个原因可能导致此异常:区域的中心点无效,或区域的跨度无效.

要避免此异常:
1)检查中心点值:纬度在[-90; 90]范围内,经度在[-180; 180]范围内
2)使用[mapView regionThatFits:region]获取有效范围的区域然后设置为mapview:
[mapView setRegion:[mapView regionThatFits:region]]

Answer 3

调用 后startUpdatingLocation，位置可能需要几秒钟的时间才能更新，因此您无法随后尝试立即检索它。在更新之前，位置包含无效值，这就是错误告诉您的内容。

相反，实现locationManager:didUpdateToLocation:fromLocation:委托方法并读取其中的位置。

将后面的 所有代码移至startUpdatingLocation该方法：

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    CLLocation *location = [locationManager location];
    //etc...
}

注：以上方法已降价：