Clustering for MKAnnotationView.
Objective-C Shell
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README.md

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Clustered annotations

Annotation clustering to show a high number of pins without cluttering the screen. This uses the k-means algorithm to do the clustering.

There will be bugs. Also, the code is complicated, maybe there is no other way to do this.

Logic to expand/contract nodes

  • lastSelectedCluster
  • lastSelectedAnnotation

  • didAdd:

         if (added is kind of cluster){
             // animate fade in
         } else if (added is kind of annotation){
             // animate fade in and position expand
         }
  • select: objective-c if (selected isKindOf cluster){ if (lastSelectedCluster == cluster){ // case where the same cluster is selected, nothing changes } else { // case where a different cluster is selected // remove last cluster with lastSelectedCluster: - contract and remove children // Note: To access the views of the children you need each // child to keep a reference to its view. // This can be done in the viewForAnnotation method. - remove lastSelectedCluster // add new cluster lastSelectedCluster = cluster with lastSelectedCluster: - add and expand children } } else if (lastSelectedCluster isKindOf annotation){ lastSelectedAnnotation = annotation }
  • deselect: objective-c if (deselected == lastSelectedCluster){ // we deselected the cluster.. if (lastSelectedAnnotation == nil){ // ..because we clicked on the ground } else if (lastSelectedAnnotation is child of lastSelectedCluster){ // ..because we clicked on one of its children // nothing to do } else { // .. because we clicked on a foreign annotation // do the removal thing (but probably we never reach this case) } } else if (deselected is kind of annotation){ // we deselected an annotation // nothing to do } else if (deselected is kind of cluster){ // we deselected a cluster which isn't the lastSelectedCluster // this shouldn't happen }