iOS - 如何将MapView限制为特定区域？ [英] iOS - How to limit the MapView to a specific region?

问题描述

我有以下问题：

我有一个绘制地图（图像），我将其作为叠加添加到MapView。没有问题......但是我需要将MapView限制在Overlay的区域，因此用户无法在此区域之外滚动/缩放..但是应该可以在bounds内滚动/缩放叠加层 - 意味着我不能只为MapView禁用缩放/滚动。

I have a "drawn map" (image) which I add to the MapView as an Overlay. No Problem with that.. but I need to limit the MapView to the region of the Overlay, so a user isn't able to scroll/zoom outside of this region.. but it should be possible to scroll/zoom inside the "bounds" of the overlay - means I cannot just disable zoom/scrolling for the MapView.

这个主题是否有任何想法/解决方案？使用MapView / -Kit的原因是我需要将各种POI添加到自定义地图。当使用ImageView + ScrollView呈现自定义地图时，这可能会变得更加复杂。

Are there any ideas/solution on this topic? The reason for using the MapView/-Kit is that I need to add various POIs to the custom map. This may become more complex when just using an ImageView+ScrollView for presenting the custom map.

我已经研究了很多这个主题，但我没有找到一个好的解决方案。

I've researched alot on this topic, but I didn't found a nice solution.

感谢任何帮助！

最好的问候，
Christian

Best Regards, Christian

编辑：这是我们的解决方案：
您提供了一个topleft和一个底部坐标来限制地图。 （最小）缩放级别也是有限的。我已经停用了减速功能，你可以从地图中弹出一点（为了更好的性能/ ux）。我在叠加层上添加了一个〜1km的灰色边框，这样用户就无法看到google的orignal worldmap。

LimitedMapView.h：

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>


@interface LimitedMapView : MKMapView <UIScrollViewDelegate>{

}

@property (nonatomic, assign) CLLocationCoordinate2D topLeftCoordinate;
@property (nonatomic, assign) CLLocationCoordinate2D bottomRightCoordinate;


@end

LimitedMapView.m：

#import "LimitedMapView.h"

@implementation LimitedMapView

@synthesize topLeftCoordinate, bottomRightCoordinate;

- (void)scrollViewDidZoom:(UIScrollView *)scrollView{

    if([super respondsToSelector:@selector(scrollViewDidZoom:)]) [super scrollViewDidZoom:scrollView];

    if ([self region].span.latitudeDelta > 0.002401f || [self region].span.longitudeDelta > 0.003433f) {

        CLLocationCoordinate2D center = self.centerCoordinate;
        MKCoordinateSpan span = MKCoordinateSpanMake(0.002401f, 0.003433f);

        self.region = MKCoordinateRegionMake(center, span);

    }

}

-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{

    if([super respondsToSelector:@selector(scrollViewDidEndDragging:)]) [super scrollViewDidEndDragging:scrollView willDecelerate:decelerate];

    MKCoordinateRegion currentRegion = self.region;
    bool changeRegionLong = YES;
    bool changeRegionLat = YES;

    // LONGITUDE    
    if((currentRegion.center.longitude - (currentRegion.span.longitudeDelta/2)) < self.topLeftCoordinate.longitude) {

        currentRegion.center.longitude = (topLeftCoordinate.longitude + (currentRegion.span.longitudeDelta/2));

    } else if((currentRegion.center.longitude + (currentRegion.span.longitudeDelta/2)) > self.bottomRightCoordinate.longitude) {

        currentRegion.center.longitude = (bottomRightCoordinate.longitude - (currentRegion.span.longitudeDelta/2));

    } else {

        changeRegionLong = NO;

    }

    // LATITUDE    
    if((currentRegion.center.latitude + (currentRegion.span.latitudeDelta/2)) > self.topLeftCoordinate.latitude) {

        currentRegion.center.latitude = (topLeftCoordinate.latitude - (currentRegion.span.latitudeDelta/2));

    } else if((currentRegion.center.latitude - (currentRegion.span.latitudeDelta/2)) < self.bottomRightCoordinate.latitude) {

        currentRegion.center.latitude = (bottomRightCoordinate.latitude + (currentRegion.span.latitudeDelta/2));

    } else {

        changeRegionLat = NO;

    }

    if(changeRegionLong || changeRegionLat) [self setRegion:currentRegion animated:YES];

}

-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{

    [scrollView setContentOffset:scrollView.contentOffset animated:YES];
}

@end

推荐答案

通过实施：

- （void）mapView：（MKMapView *）mapView regionWillChangeAnimated：（BOOL）animated

您应该可以将区域重置为您的特定区域。

You should be able to reset region to your specific one.

看该答案以举例说明如何执行此操作。

Look at that answer to have an example of how to do this.

另一个解决方案，它带来更精确的事件，但更复杂 （我目前正在成功使用此功能以满足其他需求）是子类 MKMapView 并覆盖 UIScrollViewDelegate 协议。

Another solution, that brings more precise events but is more complex (I'm currently using this successfully for another need) is to subclass MKMapView and override UIScrollViewDelegate protocol.

如果你这样做，请务必按照以下方式调用 super 实现：

If you do that, make sure to call super implementation like that :

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
  if ([super respondsToSelector:@selector(scrollViewWillBeginDragging:)])
    [super scrollViewWillBeginDragging:scrollView];
  // do what you want
}

注意：虽然协议是公共的， MKMapView 实现是未知的，可能与iOS版本不同，因此使用 respondsToSelector检查更安全：之前。你必须调用超级实现，否则Map将无法正常工作。

Note: While the protocol is public, MKMapView implementation is unknown and might differ with iOS versions, so it is more safe to check with respondsToSelector: before. You must call super implementations or Map will just not work properly.

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