Question

我无法使用位置服务获取我使用ArcGIS的位置。以下是代码的一部分：

-(void)viewDidLoad {
    [super viewDidLoad];
    [self.activityView startAnimating];
    //self.mapView.layerDelegate = self;
    self.mapView.touchDelegate = self;
    self.mapView.calloutDelegate = self;
    NSURL *mapUrl = [NSURL URLWithString:kTiledMapServiceURL];
    AGSTiledMapServiceLayer *tiledLyr = [AGSTiledMapServiceLayer tiledMapServiceLayerWithURL:mapUrl];
    [self.mapView addMapLayer:tiledLyr withName:@"Tiled Layer"];

        //Create Bus Graphic layer
    AGSGraphicsLayer *busGraphicLayer = [AGSGraphicsLayer graphicsLayer];
    [self.mapView addMapLayer:busGraphicLayer withName:@"BusLayer"];

//Create Graphic layer
    AGSGraphicsLayer *graphicLayer = [AGSGraphicsLayer graphicsLayer];
    [self.mapView addMapLayer:graphicLayer withName:@"GraphicsLayer"];

    //Create Service layer
    AGSGraphicsLayer *serviceLayer = [AGSGraphicsLayer graphicsLayer];
    [self.mapView addMapLayer:serviceLayer withName:@"ServiceLayer"];

    //Create Path layer
    AGSGraphicsLayer *pathLayer = [AGSGraphicsLayer graphicsLayer];
    [self.mapView addMapLayer:pathLayer withName:@"PathLayer"];
 }

- (void) showMarkingOnMap:(Service *) ser
{
    id<AGSLayerView> graphicsLayerView = [self.mapView.mapLayerViews objectForKey:@"ServiceLayer"];
    AGSGraphicsLayer *graphicsLayer = (AGSGraphicsLayer*)graphicsLayerView.agsLayer;
    [graphicsLayer removeAllGraphics];

    // Create a symbols png graphic
    AGSPictureMarkerSymbol *genSymbol = [AGSPictureMarkerSymbol pictureMarkerSymbolWithImageNamed:@"pushpin.png"];
    ServiceInfoTemplate *infoTemplate = [[ServiceInfoTemplate alloc] init];
    AGSGraphic *genGraphic;
    AGSPoint *genPt;
    NSMutableDictionary *dic= [[NSMutableDictionary alloc] init];
    [dic setObject:[ser name] forKey:@"NAME"];
    if([ser.location isEqualToString: @"\n"] || (ser.location == nil)){
        [dic setObject:@"" forKey:@"DESC"];
    } else {
        [dic setObject:[ser location] forKey:@"DESC"];
    }
    genPt = [AGSPoint pointWithX:[[ser xcoordinate] floatValue]
                                y:[[ser ycoordinate] floatValue]
                 spatialReference:self.mapView.spatialReference];

    destinationX = [[ser xcoordinate] floatValue];
    destinationY = [[ser ycoordinate] floatValue];

    genGraphic = [[AGSGraphic alloc] initWithGeometry:genPt symbol:genSymbol attributes:dic infoTemplateDelegate:infoTemplate];
    [graphicsLayer addGraphic:genGraphic];

    [graphicsLayer dataChanged];

    [self.mapView zoomWithFactor:0.1 atAnchorPoint:CGPointMake(destinationX, destinationY) animated:NO];
    [self.mapView centerAtPoint:genPt animated:YES];
}

此方法是我调用当前位置的地方

- (IBAction) directionAction:(id)sender{
    NSString *format = [NSString stringWithFormat:@"http://www....&routeStops=%f,%f;%f,%f&routemode=DRIVE&avoidERP=0"",         
                        self.mapView.gps.currentPoint.x, self.mapView.gps.currentPoint.y, destinationX, destinationY];

}

这个self.mapView.gps.currentPoint.x给我一个0，但它应该返回我当前的x坐标。任何人都知道它有什么问题吗？

Answer 1

我没有从您的代码中看到您在mapView上启用了gps对象。您需要先将enable property设置为YES才能启用它。然后在尝试使用currentPoint之前等待gps获得有效位置（currentPoint！= nil）。您可以在currentPoint属性上设置键值观察器，并等待它更改的通知，并检查它是否有效，然后使用它。

self.mapView.gps.enabled = YES;   // enable the GPS

// add the observer like this:
[self.mapView.gps addObserver:self forKeyPath:@"currentPoint" options:0 context:nil];

然后添加一个方法以在更改时收到通知：

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if ([keyPath isEqualToString:@"currentPoint"]) {
        AGSPoint *point = self.mapView.gps.currentPoint;
        if (point==nil) return;

        // now we have a valid gps location
    }
}

希望能给你一些想法。

ArcGIS当前位置

1 个答案: