Question

我制作了一个计数步骤应用程序，我用iPhone加速计计算步数，现在我想显示我在mapView上创建的路径。我可以轻松地显示地图并使用iPhone GPS捕捉到正确的位置，我可以显示起点和终点，我可以绘制折线来显示我制作的路径。现在我的问题是如何在地图上设置正确的缩放？当我用地图打开ViewController时，缩放它太远了，我要缩放以查看我制作的路径。所以我的问题是如何设置正确的缩放？

我在这里发布了带有mapView的视图控制器的代码：

ResultViewController.m

#import "ResultViewController.h"
#import "MapAnnotation.h"

@interface ResultViewController ()
@property (nonatomic, strong)NSMutableArray *mapAnnotation;
@property (nonatomic) BOOL needUpdateRegion;
@end

@implementation ResultViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.labelResult.text = self.totalSteps;
    [self.mapView setDelegate:self];
    self.needUpdateRegion = YES;
    self.mapAnnotation = [[NSMutableArray alloc]initWithCapacity:2];
    CLLocation *startLocation = [self.locationArray objectAtIndex:0];
    CLLocation *stopLocation = [self.locationArray lastObject];
    NSString *startLatitude = [NSString stringWithFormat:@"%f", startLocation.coordinate.latitude];
    NSString *startLongitude = [NSString stringWithFormat:@"%f", startLocation.coordinate.longitude];
    NSString *stopLatitude = [NSString stringWithFormat:@"%f", stopLocation.coordinate.latitude];
    NSString *stopLongitude = [NSString stringWithFormat:@"%f", stopLocation.coordinate.longitude];

    MapAnnotation *startPlace = [[MapAnnotation alloc]initWithCoordinate:startLatitude andLong:startLongitude];
    MapAnnotation *stopPlace = [[MapAnnotation alloc]initWithCoordinate:stopLatitude andLong:stopLongitude];

    [self.mapAnnotation insertObject:startPlace atIndex:0];
    [self.mapAnnotation insertObject:stopPlace atIndex:1];

    if (self.mapAnnotation) {
        [self.mapView removeAnnotations:self.mapView.annotations];
    }

    [self.mapView addAnnotation:self.mapAnnotation[0]];
    [self.mapView addAnnotation:self.mapAnnotation[1]];
    [self updateRegion];
    [self createMKpolylineAnnotation];
}

- (void)updateRegion
{
    self.needUpdateRegion = NO;
    CGRect boundingRect;
    BOOL started = NO;
    for (id <MKAnnotation> annotation in self.mapView.annotations) {
        CGRect annotationRect = CGRectMake(annotation.coordinate.latitude, annotation.coordinate.longitude, 0, 0);
        if (!started) {
            started = YES;
            boundingRect = annotationRect;
        } else {
            boundingRect = CGRectUnion(boundingRect, annotationRect);
        }
    }
    if (started) {
        boundingRect = CGRectInset(boundingRect, -0.2, -0.2);
        if ((boundingRect.size.width < 20) && (boundingRect.size.height < 20)) {
            MKCoordinateRegion region;
            region.center.latitude = boundingRect.origin.x + boundingRect.size.width / 2;
            region.center.longitude = boundingRect.origin.y + boundingRect.size.height / 2;
            region.span.latitudeDelta = boundingRect.size.width;
            region.span.longitudeDelta = boundingRect.size.height;
            [self.mapView setRegion:region animated:YES];
        }
    }
}

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {
    MKPolylineView *polylineView = [[MKPolylineView alloc] initWithPolyline:overlay];
    polylineView.strokeColor = [UIColor blueColor];
    polylineView.lineWidth = 5.0;

    return polylineView;
}


- (void)createMKpolylineAnnotation {
    NSInteger numberOfSteps = self.locationArray.count;

    CLLocationCoordinate2D *coords = malloc(sizeof(CLLocationCoordinate2D) * numberOfSteps);
    for (NSInteger index = 0; index < numberOfSteps; index++) {
        CLLocation *location = [self.locationArray objectAtIndex:index];
        CLLocationCoordinate2D coordinate = location.coordinate;
        coords[index] = coordinate;
    }

    MKPolyline *polyLine = [MKPolyline polylineWithCoordinates:coords count:numberOfSteps];
    [self.mapView addOverlay:polyLine];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)restart:(id)sender {
    [self dismissViewControllerAnimated:YES completion:nil];
}
@end

这段代码有什么问题？有人可以帮我正确缩放地图吗？

谢谢

Answer 1

在这种情况下，我建议您调用以下方法以缩放到地图的某个区域，您可以在方法的末尾添加调用- (void)createMKpolylineAnnotation;

拨打：

[self zoomToPolyLine: self.mapView polyLine:polyLine animated:YES];

方式：

-(void)zoomToPolyLine:(MKMapView*)map polyLine:(MKPolyline*)polyLine animated:(BOOL)animated { MKPolygon* polygon = [MKPolygon polygonWithPoints:polyLine.points count:polyLine.pointCount]; [map setRegion:MKCoordinateRegionForMapRect([polygon boundingMapRect]) animated:animated]; }

Answer 2

首先在视图中添加此行，在将mapview委托设置为

后执行加载

[self.mapView setDelegate:self];
    self.needUpdateRegion = YES;
    mapView.zoomEnabled = YES;
    mapView.scrollEnabled = YES;

...

}

然后修改以下行以根据您的要求设置缩放级别60000 = 60 km ..

 [mapView setRegion: MKCoordinateRegionMakeWithDistance(site.coordinate, 60000, 60000)  animated:YES];

或者您可以尝试使用此方法将缩放比例设置为

    - (void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context {
    CGImageRef imageReference = self.overlayImage.CGImage;

    MKMapRect theMapRect = self.overlay.boundingMapRect;
    CGRect theRect = [self rectForMapRect:theMapRect];

    CGContextScaleCTM(context, 1.0, -1.0);
    CGContextTranslateCTM(context, 0.0, -theRect.size.height);
    CGContextDrawImage(context, theRect, imageReference);
}

希望这可以帮助你......干杯!!

在MKMapView中设置正确的缩放

2 个答案: