百度地图之标注物聚合

在博客《百度地图查询视野范围内的建筑物》当中描述了如何查询视野范围内的建筑物，可以减少地图加载标注物的数量，提升速度。但是当地图的zoom级很小时，会出现标注物重叠的现象，不是很美观，所以下面的文章将介绍地图标注物如何根据zoom的大小聚合显示。 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

//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.getSnippet()); clusterMarker.AddMarker(marker,isAverageCenter); clusterMarker.AddMarker(marker,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; } }

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