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我使用我的自定义子类 MKAnnotationView。在我的 Map 委托的mapView:didSelectAnnotationView:方法中，我调用了这个类的方法，它将带有图像的 UIImageView 添加为子视图 - 它用作我的自定义注释标注。

当使用默认的 MKPinAnnotationView 地图时，地图会自动调整地图区域以显示刚刚出现的注释标注。如何使用自定义 MKAnnotationView 子类实现此行为？

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2 回答 2

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当前解决方案

我制作了演示项目，实现了下面讨论的内容：请参阅 AdjustRegionToFitAnnotationCallout项目。

Map Kit 的 MKMapView 如何呈现地图注释的最新 iOS7 更改让我重新审视了这个问题。我对此进行了更准确的思考，并提出了非常非常好的解决方案。我将把以前的解决方案留在这个答案的底部，但请记住 - 当我这样做时我错了。

首先，我们需要一个帮助器CGRectTransformToContainRect()来扩展一个给定CGRect的以包含另一个CGRect。

注意：它的行为与它的行为不同CGRectUnion()-只返回包含两者CGRectUnion()的最小的，而下面的助手允许平行移动，即等于而不是喜欢它。当我们只想使用平行移动进行调整并希望避免地图的缩放时，这种行为正是我们所需要的。CGRectCGRectsCGRectTransformToContainRect(CGRectMake(0, 0, 100, 100), CGRectMake(50, 50, 100, 100))(CGRect){50, 50, 100, 100}(CGRect){0, 0, 150, 150}CGRectUnion()

static inline CGRect CGRectTransformToContainRect(CGRect rectToTransform, CGRect rectToContain) {
    CGFloat diff;
    CGRect transformedRect = rectToTransform;


    // Transformed rect dimensions should encompass the dimensions of both rects
    transformedRect.size.width = MAX(CGRectGetWidth(rectToTransform), CGRectGetWidth(rectToContain));
    transformedRect.size.height = MAX(CGRectGetHeight(rectToTransform), CGRectGetHeight(rectToContain));


    // Comparing max X borders of both rects, adjust if
    if ((diff = CGRectGetMaxX(rectToContain) - CGRectGetMaxX(transformedRect)) > 0) {
        transformedRect.origin.x += diff;
    }
    // Comparing min X borders of both rects, adjust if
    else if ((diff = CGRectGetMinX(transformedRect) - CGRectGetMinX(rectToContain)) > 0) {
        transformedRect.origin.x -= diff;
    }


    // Comparing max Y borders of both rects, adjust if
    if ((diff = CGRectGetMaxY(rectToContain) - CGRectGetMaxY(transformedRect)) > 0) {
        transformedRect.origin.y += diff;
    }
    // Comparing min Y borders of both rects, adjust if
    else if ((diff = CGRectGetMinY(transformedRect) - CGRectGetMinY(rectToContain)) > 0) {
        transformedRect.origin.y -= diff;
    }


    return transformedRect;
}

Adjust method wrapped into an Objective-C category MKMapView(Extensions):

@implementation MKMapView (Extensions)

- (void)adjustToContainRect:(CGRect)rect usingReferenceView:(UIView *)referenceView  animated:(BOOL)animated {
    // I just like this assert here
    NSParameterAssert(referenceView);

    CGRect visibleRect = [self convertRegion:self.region toRectToView:self];

    // We convert our annotation from its own coordinate system to a coodinate system of a map's top view, so we can compare it with the bounds of the map itself
    CGRect annotationRect = [self convertRect:rect fromView:referenceView.superview];

    // Fatten the area occupied by your annotation if you want to have a margin after adjustment
    CGFloat additionalMargin = 2;
    adjustedRect.origin.x -= additionalMargin;
    adjustedRect.origin.y -= additionalMargin;
    adjustedRect.size.width += additionalMargin * 2;
    adjustedRect.size.height += additionalMargin * 2;

    // This is the magic: if the map must expand its bounds to contain annotation, it will do this 
    CGRect adjustedRect = CGRectTransformToContainRect(visibleRect, annotationRect);

    // Now we just convert adjusted rect to a coordinate region
    MKCoordinateRegion adjustedRegion = [self convertRect:adjustedRect toRegionFromView:self];

    // Trivial regionThatFits: sugar and final setRegion:animated: call
    [self setRegion:[self regionThatFits:adjustedRegion] animated:animated];
}

@end

现在控制器和视图：

@interface AnnotationView : MKAnnotationView
@property AnnotationCalloutView *calloutView;
@property (readonly) CGRect annotationViewWithCalloutViewFrame;
@end

@implementation AnnotationView 

- (void)showCalloutBubble {
    // This is a code where you create your custom annotation callout view
    // add add it using -[self addSubview:]
    // At the end of this method a callout view should be displayed.
}

- (CGRect)annotationViewWithCalloutViewFrame {
    // Here you should adjust your annotation frame so it match itself in the moment when annotation callout is displayed and ...

    return CGRectOfAdjustedAnnotation; // ...
}

@end

当在地图上选择 AnnotationView 类注解时，会将其calloutView添加为子视图，从而显示自定义注解标注视图。它是使用 MKMapViewDelegate 的方法完成的：

- (void)mapView:(MapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view {
    // AnnotationPresenter is just a class that contains information to be displayed on callout annotation view
    if ([view.annotation isKindOfClass:[AnnotationPresenter class]]) {
        // Hide another annotation if it is shown
        if (mapView.selectedAnnotationView != nil && [mapView.selectedAnnotationView isKindOfClass:[AnnotationView class]] && mapView.selectedAnnotationView != view) {
            [mapView.selectedAnnotationView hideCalloutBubble];
        }
        mapView.selectedAnnotationView = view;

        annotationView *annotationView = (annotationView *)view;

        // This just adds *calloutView* as a subview    
        [annotationView showCalloutBubble];

        [mapView adjustToContainRect:annotationView.annotationViewWithCalloutViewFrame usingReferenceView:annotationView animated:NO];
    }
}

当然，您的实现可能与我在这里描述的不同（我的是！）。上面代码中最重要的部分当然是[MKMapView adjustToContainRect:usingReferenceView:animated:方法。现在我对当前的解决方案以及我对这个（以及一些相关）问题的理解感到非常满意。如果您需要对上述解决方案有任何意见，请随时与我联系（参见个人资料）。

以下 Apple 文档对于了解 -[MKMapView convertRect:fromView:] 等方法中发生的情况非常有用：

http://developer.apple.com/library/ios/#documentation/MapKit/Reference/MKMapView_Class/MKMapView/MKMapView.html

http://developer.apple.com/library/ios/#documentation/MapKit/Reference/MapKitDataTypesReference/Reference/reference.html

http://developer.apple.com/library/ios/#documentation/MapKit/Reference/MapKitFunctionsReference/Reference/reference.html

此外，WWDC 2013 会议的前 10-15 分钟“Map Kit 中的新功能”（#304）非常值得观看，以观看由 Apple 工程师完成的整个“带注释的地图”设置的出色快速演示。

初步解决方案（iOS7下不行，不要用，改用上面的方案）

不知怎的，我一次忘了回答我的问题。这是我现在使用的完整解决方案（为了便于阅读，稍作编辑）：

首先，将一些地图逻辑封装在帮助文件（如 MapKit+Helpers.h）中的某个位置

typedef struct {
    CLLocationDegrees top;
    CLLocationDegrees bottom;
} MKLatitudeEdgedSpan;

typedef struct {
    CLLocationDegrees left;
    CLLocationDegrees right;
} MKLongitudeEdgedSpan;

typedef struct {
    MKLatitudeEdgedSpan latitude;
    MKLongitudeEdgedSpan longitude;
} MKEdgedRegion;

MKEdgedRegion MKEdgedRegionFromCoordinateRegion(MKCoordinateRegion region) {
    MKEdgedRegion edgedRegion;

    float latitude = region.center.latitude;
    float longitude = region.center.longitude;
    float latitudeDelta = region.span.latitudeDelta;
    float longitudeDelta = region.span.longitudeDelta;

    edgedRegion.longitude.left = longitude - longitudeDelta / 2;
    edgedRegion.longitude.right = longitude + longitudeDelta / 2;
    edgedRegion.latitude.top = latitude + latitudeDelta / 2;
    edgedRegion.latitude.bottom = latitude - latitudeDelta / 2;

    return edgedRegion;
}

与 MKCoordinateRegion（中心坐标 + 跨度）一样，MKEdgedRegion 只是一种定义区域的方法，但使用的是其边缘的坐标。

MKEdgedRegionFromCoordinateRegion() 是一种不言自明的转换器方法。

假设我们的注释有以下类，包含它的标注作为子视图。

@interface AnnotationView : MKAnnotationView
@property AnnotationCalloutView *calloutView;
@end

当在地图上选择 AnnotationView 类注解时，会将其calloutView添加为子视图，从而显示自定义注解标注视图。它是使用 MKMapViewDelegate 的方法完成的：

- (void)mapView:(MapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view {
    // AnnotationPresenter is just a class that contains information to be displayed on callout annotation view
    if ([view.annotation isKindOfClass:[AnnotationPresenter class]]) {
        // Hide another annotation if it is shown
        if (mapView.selectedAnnotationView != nil && [mapView.selectedAnnotationView isKindOfClass:[AnnotationView class]] && mapView.selectedAnnotationView != view) {
            [mapView.selectedAnnotationView hideCalloutBubble];
        }
        mapView.selectedAnnotationView = view;

        annotationView *annotationView = (annotationView *)view;

        // This just adds *calloutView* as a subview    
        [annotationView showCalloutBubble];

        /* Here the trickiest piece of code goes */

        /* 1. We capture _annotation's (not callout's)_ frame in its superview's (map's!) coordinate system resulting in something like (CGRect){4910547.000000, 2967852.000000, 23.000000, 28.000000} The .origin.x and .origin.y are especially important! */
        CGRect annotationFrame = annotationView.frame;

        /* 2. Now we need to perform an adjustment, so our frame would correspond to the annotation view's _callout view subview_ that it holds. */
        annotationFrame.origin.x = annotationFrame.origin.x + ANNOTATION_CALLOUT_TRIANLE_HALF; // Mine callout view has small x offset - you should choose yours!
        annotationFrame.origin.y = annotationFrame.origin.y - ANNOTATION_CALLOUT_HEIGHT / 2; // Again my custom offset.
        annotationFrame.size = placeAnnotationView.calloutView.frame.size; // We can grab calloutView size directly because in its case we don't care about the coordinate system.

        MKCoordinateRegion mapRegion = mapView.region;

        /* 3. This was a long run before I did stop to try to pass mapView.view as an argument to _toRegionFromView_. */
        /* annotationView.superView is very important - it gives us the same coordinate system that annotationFrame.origin is based. */
        MKCoordinateRegion annotationRegion = [mapView convertRect:annotationFrame toRegionFromView:annotationView.superview];

        /* I hope that the following MKEdgedRegion magic is self-explanatory */
        MKEdgedRegion mapEdgedRegion = MKEdgedRegionFromCoordinateRegion(mapRegion);
        MKEdgedRegion annotationEdgedRegion = MKEdgedRegionFromCoordinateRegion(annotationRegion);

        float diff;

        if ((diff = (annotationEdgedRegion.longitude.left - mapEdgedRegion.longitude.left)) < 0 ||
            (diff = (annotationEdgedRegion.longitude.right - mapEdgedRegion.longitude.right)) > 0)
            mapRegion.center.longitude += diff;

        if ((diff = (annotationEdgedRegion.latitude.bottom - mapEdgedRegion.latitude.bottom)) < 0 ||
            (diff = (annotationEdgedRegion.latitude.top - mapEdgedRegion.latitude.top)) > 0)
            mapRegion.center.latitude += diff;

        mapView.region = mapRegion;
    }
}
于 2013-01-11T03:03:11.550 回答
0

我一直在寻找类似的解决方案，以在屏幕的可见矩形中适应路线和标注。我尝试了一些解决方案，但最终只设置了足够的填充setVisibleMapRect:edgePadding:animated:。可能没有那么复杂，但基本上可以满足我的需要。

MKMapRect routeMapRect = myRoute.polyline.boundingMapRect;
CGFloat padding = myCallout.bounds.width / 2.0;
[myMapView setVisibleMapRect: routeMapRect edgePadding:UIEdgeInsetsMake(padding, padding, padding, padding) animated:YES];

当然，这可以更加优化，例如通过检测您实际需要填充的一侧并在另一侧设置较小的填充。但你明白了。

于 2016-01-15T09:49:11.757 回答