MAMapKit 点聚合
| 类 | 接口 | 说明 | 版本 |
|---|---|---|---|
| AnnotationClusterViewController | - (void)searchPoiWithKeyword:(NSString *)keyword; | 根据关键字搜索poi点 | n/a |
| CoordinateQuadTree | - (void)buildTreeWithPOIs:(NSArray *)pois; | 根据返回poi建树 | n/a |
| AnnotationClusterViewController | - (void)addAnnotationsToMapView:(MAMapView *)mapView; | 把annotation添加到地图 | n/a |
| AnnotationClusterViewController | - (void)mapView:(MAMapView *)mapView regionDidChangeAnimated:(BOOL)animated; | 响应地图区域变化回调，刷新annotations | n/a |
- 调用ClusterAnnotation文件夹下的代码能够实现poi点聚合，使用步骤如下：
- 初始化coordinateQuadTree。
Objective-C
self.coordinateQuadTree = [[CoordinateQuadTree alloc] init];
Swift
var coordinateQuadTree = CoordinateQuadTree()
- 获得poi数组pois后，创建coordinateQuadTree。
- 项目Demo通过关键字搜索获得poi数组数据，具体见工程。此处从获得poi数组开始说明。
- 创建四叉树coordinateQuadTree来建立poi的四叉树索引。
- 创建过程较为费时，建议另开线程。创建四叉树完成后，计算当前mapView下需要显示的annotation。
Objective-C
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
/* 建立四叉树. */
[self.coordinateQuadTree buildTreeWithPOIs:respons.pois];
dispatch_async(dispatch_get_main_queue(), ^{
/* 计算当前mapView区域内需要显示的annotation. */
NSLog(@"First time calculate annotations.");
[self addAnnotationsToMapView:self.mapView];
});
});Swift
DispatchQueue.global(qos: .default).async(execute: { [weak self] in
self?.coordinateQuadTree.build(withPOIs: response.pois)
self?.shouldRegionChangeReCalculate = true
self?.addAnnotations(toMapView: (self?.mapView)!)
})
- 根据CoordinateQuadTree四叉树索引，计算当前zoomLevel下，mapView区域内的annotation。
Objective-C
- (void)addAnnotationsToMapView:(MAMapView *)mapView
{
/* 判断是否已建树. */
if (self.coordinateQuadTree.root == nil)
{
return;
}
/* 根据当前zoomLevel和zoomScale 进行annotation聚合. */
double zoomScale = self.mapView.bounds.size.width / self.mapView.visibleMapRect.size.width;
/* 基于先前建立的四叉树索引，计算当前需要显示的annotations. */
NSArray *annotations = [self.coordinateQuadTree clusteredAnnotationsWithinMapRect:mapView.visibleMapRect
withZoomScale:zoomScale
andZoomLevel:mapView.zoomLevel];
/* 更新annotations. */
[self updateMapViewAnnotationsWithAnnotations:annotations];
}Swift
func addAnnotations(toMapView mapView: MAMapView) {
synchronized(lock: self) { [weak self] in
guard (self?.coordinateQuadTree.root != nil) || self?.shouldRegionChangeReCalculate != false else {
NSLog("tree is not ready.")
return
}
guard let aMapView = self?.mapView else {
return
}
let visibleRect = aMapView.visibleMapRect
let zoomScale = Double(aMapView.bounds.size.width) / visibleRect.size.width
let zoomLevel = Double(aMapView.zoomLevel)
DispatchQueue.global(qos: .default).async(execute: { [weak self] in
let annotations = self?.coordinateQuadTree.clusteredAnnotations(within: visibleRect, withZoomScale: zoomScale, andZoomLevel: zoomLevel)
self?.updateMapViewAnnotations(annotations: annotations as! Array<ClusterAnnotation>)
})
}
}
- 更新annotations。对比mapView里已有的annotations，吐故纳新。
Objective-C
/* 更新annotation. */
- (void)updateMapViewAnnotationsWithAnnotations:(NSArray *)annotations
{
/* 用户滑动时，保留仍然可用的标注，去除屏幕外标注，添加新增区域的标注 */
NSMutableSet *before = [NSMutableSet setWithArray:self.mapView.annotations];
[before removeObject:[self.mapView userLocation]];
NSSet *after = [NSSet setWithArray:annotations];
/* 保留仍然位于屏幕内的annotation. */
NSMutableSet *toKeep = [NSMutableSet setWithSet:before];
[toKeep intersectSet:after];
/* 需要添加的annotation. */
NSMutableSet *toAdd = [NSMutableSet setWithSet:after];
[toAdd minusSet:toKeep];
/* 删除位于屏幕外的annotation. */
NSMutableSet *toRemove = [NSMutableSet setWithSet:before];
[toRemove minusSet:after];
/* 更新. */
dispatch_async(dispatch_get_main_queue(), ^{
[self.mapView addAnnotations:[toAdd allObjects]];
[self.mapView removeAnnotations:[toRemove allObjects]];
});
}Swift
func updateMapViewAnnotations(annotations: Array<ClusterAnnotation>) {
/* 用户滑动时，保留仍然可用的标注，去除屏幕外标注，添加新增区域的标注 */
let before = NSMutableSet(array: mapView.annotations)
before.remove(mapView.userLocation)
let after: Set<NSObject> = NSSet(array: annotations) as Set<NSObject>
/* 保留仍然位于屏幕内的annotation. */
var toKeep: Set<NSObject> = NSMutableSet(set: before) as Set<NSObject>
toKeep = toKeep.intersection(after)
/* 需要添加的annotation. */
let toAdd = NSMutableSet(set: after)
toAdd.minus(toKeep)
/* 删除位于屏幕外的annotation. */
let toRemove = NSMutableSet(set: before)
toRemove.minus(after)
DispatchQueue.main.async(execute: { [weak self] () -> Void in
self?.mapView.addAnnotations(toAdd.allObjects)
self?.mapView.removeAnnotations(toRemove.allObjects)
})
}
<UIViewController>AnnotationClusterViewControllerpoi点聚合PoiDetailViewController显示poi详细信息列表
MAAnnotationViewClusterAnnotationView自定义的聚合annotationView
Conform to <MAAnnotation>ClusterAnnotation记录annotation的信息，如其代表的poi数组、poi的个数、poi平均坐标，并提供两个annotation是否Equal的判断
CoordinateQuadTree封装的四叉树类QuadTree四叉树基本算法
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