俗话说站在巨人的肩膀上将事半功倍，在写android的百度地图标注物聚合时，我在网上也进行了大量的查询，发现标注物聚合的算法很早就有人写了，不过他们是js或者是Google地图c#版的。借鉴他们的想法，我写了android的这版代码与大家一起分享。
一、牛人们的想法
下面是我参考的有关的博客，下面将一一列举
1.MarkerCluster之百度地图版 http://hi.baidu.com/liongg/item/d8adece188fbfb11585dd89f
2.Marker Cluster面面观 http://hi.baidu.com/liongg/item/a380cc95bd70c2bdcd80e581
3.GoogleMap标注物聚合解决办法 http://www.svennerberg.com/2009/01/handling-large-amounts-of-markers-in-google-maps/
4.百度地图官网上已经有JS版的标注物聚合实例与原文件，建议看百度地图上的代码，规范且函数注释明确。
百度地图javascript开源库： http://developer.baidu.com/map/library.htm
二、我的思路
1.下面以一个流程图来表述我的想法。
2.下面贴出代码
- <span style="font-family:KaiTi_GB2312;"><span style="font-size:18px;">//cluster聚合器类
- package com.zhl.map;
- import java.util.ArrayList;
- import java.util.List;
- import android.graphics.Bitmap;
- import android.graphics.Point;
- import android.graphics.drawable.BitmapDrawable;
- import android.util.Log;
- import android.view.LayoutInflater;
- import android.view.View;
- import android.widget.TextView;
- import baidumapsdk.demo.R;
- import com.baidu.mapapi.cloud.Bounds;
- import com.baidu.mapapi.map.MapView;
- import com.baidu.mapapi.map.OverlayItem;
- import com.baidu.mapapi.utils.DistanceUtil;
- import com.baidu.platform.comapi.basestruct.GeoPoint;
- import com.zhl.activity.MarkerClusterActivity;
- import com.zhl.util.MapUtils;
- public class Cluster{
- private MarkerClusterActivity mMarkCluster;
- private MapView mMapView;
- private int mMinClusterSize;
- private Boolean isAverageCenter;
- private int mGridSize;
- private double mDistance;
- private List<ClusterMarker> mMarkers;
- public Cluster(MarkerClusterActivity markCluster,MapView mapView
- ,int minClusterSize,Boolean isAverageCenter
- ,int mGridSize,double mDistance) {
- this.mMarkCluster = markCluster;
- this.mMapView = mapView;
- this.mMinClusterSize = minClusterSize;
- this.isAverageCenter = isAverageCenter;
- this.mGridSize = mGridSize;
- this.mDistance = mDistance;
- mMarkers = new ArrayList<ClusterMarker>();
- }
- public List<OverlayItem> createCluster(List<OverlayItem> markerList){
- this.mMarkers.clear();
- List<OverlayItem> itemList = new ArrayList<OverlayItem>();
- for(int i=0;i<markerList.size();i++){
- addCluster(markerList.get(i));
- }
- for(int i=0;i<mMarkers.size();i++){
- ClusterMarker cm = mMarkers.get(i);
- setClusterDrawable(cm);
- OverlayItem oi = new OverlayItem(cm.getmCenter(),cm.getTitle(),cm.getSnippet());
- oi.setMarker(cm.getMarker());
- itemList.add(oi);
- }
- return itemList;
- }
- private void addCluster(OverlayItem marker){
- GeoPoint markGeo = marker.getPoint();
- if(mMarkers.size()==0){
- ClusterMarker clusterMarker = new ClusterMarker(marker.getPoint(), marker.getTitle(), marker.getSnippet());
- clusterMarker.setMarker(marker.getMarker());
- clusterMarker.AddMarker(marker, isAverageCenter);
- Bounds bound = new Bounds(markGeo.getLatitudeE6(),markGeo.getLongitudeE6(),markGeo.getLatitudeE6(),markGeo.getLongitudeE6());
- bound = MapUtils.getExtendedBounds(mMapView, bound, mGridSize);
- clusterMarker.setmGridBounds(bound);
- mMarkers.add(clusterMarker);
- }else{
- ClusterMarker clusterContain = null;
- double distance = mDistance;
- for(int i=0;i<mMarkers.size();i++){
- ClusterMarker clusterMarker = mMarkers.get(i);
- GeoPoint center = clusterMarker.getmCenter();
- double d = DistanceUtil.getDistance(center, marker.getPoint());
- if(d<distance){
- distance = d;
- clusterContain = clusterMarker;
- }
- }
- if(clusterContain == null||!isMarkersInCluster(markGeo, clusterContain.getmGridBounds())){
- ClusterMarker clusterMarker = new ClusterMarker(marker.getPoint(), marker.getTitle(), marker.getSnippet());
- clusterMarker.AddMarker(marker, isAverageCenter);
- clusterMarker.AddMarker(marker, isAverageCenter);
- Bounds bound = new Bounds(markGeo.getLatitudeE6(),markGeo.getLongitudeE6(),markGeo.getLatitudeE6(),markGeo.getLongitudeE6()); bound = MapUtils.getExtendedBounds(mMapView, bound, mGridSize);
- clusterMarker.setmGridBounds(bound);
- mMarkers.add(clusterMarker);
- }else{
- clusterContain.AddMarker(marker, isAverageCenter);
- }
- }
- }
- private void setClusterDrawable(ClusterMarker clusterMarker){
- View drawableView = LayoutInflater.from(mMarkCluster).inflate(
- R.layout.drawable_mark, null);
- TextView text = (TextView) drawableView.findViewById(R.id.drawble_mark);
- int markNum = clusterMarker.getmMarkers().size();
- if(markNum>=2){
- text.setText(markNum+"");
- if(markNum<11){
- text.setBackgroundResource(R.drawable.m0);
- }else if(markNum>10&&markNum<21){
- text.setBackgroundResource(R.drawable.m1);
- }else if(markNum>20&&markNum<31){
- text.setBackgroundResource(R.drawable.m2);
- }else if(markNum>30&&markNum<41){
- text.setBackgroundResource(R.drawable.m3);
- }else{
- text.setBackgroundResource(R.drawable.m4);
- }
- Bitmap bitmap = MapUtils.convertViewToBitmap(drawableView);
- clusterMarker.setMarker(new BitmapDrawable(bitmap));
- }else{
- }
- }
- private Boolean isMarkersInCluster(GeoPoint markerGeo,Bounds bound){
- if(markerGeo.getLatitudeE6()>bound.leftBottom.getLatitudeE6()
- &&markerGeo.getLatitudeE6()<bound.rightTop.getLatitudeE6()
- &&markerGeo.getLongitudeE6()>bound.rightTop.getLongitudeE6()
- &&markerGeo.getLongitudeE6()<bound.leftBottom.getLongitudeE6()){
- return true;
- }
- return false;
- }
- }</span></span>
3.工程demo代码下载，地图标注物聚合.zip
4.下面是程序的实例图片
