多源在线与离线数据读取之四（Android移动端开发读取四川地理信息中心切片底图）

本系列专题本来上次想一次性写完，无奈工作太忙，上月就中断了一个月，这个月补上两篇，在此对各位表示抱歉。

本实例主要是针对四川地理信息中心的切片，如果利用ArcGIS for Android API进行解析，并读入作用底图。

1）基础准备：下载Java版的Json解析库（http://code.google.com/p/json-simple/）、熟悉四川地理信息中心切片规则

2）关于四川地理信息中心的切片规则这就不做介绍了，在以前专题已介绍过，详见：http://www.scgis.net/

3）代码说明

AgsLOD.java:切片等级信息定义文件，在这定义了比例尽、等级、分辨率

package com.esri.arcgis.android.samples;

import com.esri.core.internal.d.c;

public class AgsLOD extends c {
private static final long serialVersiOnUID= 4341699179151728883L;
    
    private int level;
    private double resolution;
    private double scale;

    public AgsLOD(int level, double scale, double resolution) {
super();

this.level = level;
this.scale = scale;
this.resolution = resolution;
    }

    public int a() {
return this.level;
    }

    public double b() {
return this.resolution;
    }

    public double c() {
return this.scale;
    }
}

package com.esri.arcgis.android.samples;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class GetToken {
//get token
public String sendPost(String url) {  
StringBuilder result = new StringBuilder();  
        try {  
            URL httpurl = new URL(url);  
            HttpURLConnection httpCOnn= (HttpURLConnection) httpurl  
                    .openConnection();  
            httpConn.setDoInput(true);  
            BufferedReader in = new BufferedReader(new InputStreamReader(  
                    httpConn.getInputStream(),"UTF-8"));  
            String line;  
            while ((line = in.readLine()) != null) {  
                result .append(line);  
            }  
            //System.out.println(result);
            in.close(); 
            //get token
            return result.toString().split("\"")[15];
        } catch (Exception e) {  
            e.printStackTrace();           
        }
return null;
}}

SCGISModel.java：切片参数定义文件，包括切片的空间参考等基础信息

package com.esri.arcgis.android.samples;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.net.HttpURLConnection;
import java.net.URL;
import com.esri.core.geometry.Envelope;
import com.esri.core.geometry.SpatialReference;
import com.esri.core.internal.d.k;

import com.esri.core.map.TiledLayerModel;

public class SCGISModel extends TiledLayerModel {
    private static final long serialVersiOnUID= 7726567118839553087L;
    
    private String location;
    private String token;
    public SCGISModel(String location, SpatialReference sr, Envelope full,
    k tileInfo) {
super(sr, full, tileInfo);
this.location = location;
this.token=new GetToken().sendPost("http://www.scgis.net.cn/imap/iMapServer/Token/getToken?username=test20110703&password=test20110703&IpAddress=&TimeSpan=100M&st=1302073818076");
    }
        
    @Override
    public byte[] getTile(int level, int row, int col) throws Exception {
byte[] result = null;
try {
int levelCustom = level + 1;
String bundlesDir = location
+ levelCustom
+ File.separator
+ row
+ File.separator
+ col
+ "?token="+this.token;
;

ByteArrayOutputStream bos = new ByteArrayOutputStream();

URL sjwurl = new URL(bundlesDir);
HttpURLConnection httpUrl = null;
BufferedInputStream bis = null;
byte[] buf = new byte[1024];

httpUrl = (HttpURLConnection) sjwurl.openConnection();
httpUrl.connect();
bis = new BufferedInputStream(httpUrl.getInputStream());

while (true) {
int bytes_read = bis.read(buf);
if (bytes_read > 0) {
bos.write(buf, 0, bytes_read);
} else {
break;
}
}
;
bis.close();
httpUrl.disconnect();

result = bos.toByteArray();

} catch (Exception ex) {
ex.printStackTrace();
}

return result;
    }

}

SCGISMapServices.java：继承tiledLayer,自定义切片类。

package com.esri.arcgis.android.samples;
import java.util.ArrayList;
import android.content.Context;
import android.util.AttributeSet;

import com.esri.android.map.TiledLayer;
import com.esri.core.geometry.Envelope;
import com.esri.core.geometry.Point;
import com.esri.core.geometry.SpatialReference;
import com.esri.core.internal.d.c;
import com.esri.core.internal.d.k;
import com.esri.core.map.TiledLayerModel;

public class SCGISMapServices extends TiledLayer {
private String location = "http://www.scgis.net.cn/iMap/iMapServer/NewRest/services/SCTileMap/tile/";

private SpatialReference spatialReference = SpatialReference.create(4326);
private Envelope fullExtent = new Envelope(95.918, 24.898, 110.14, 35.209);
private k tileInfo;

public SCGISMapServices(Context context, AttributeSet attrs) {
super(context, attrs);
try {
init();
} catch (Exception ex) {
ex.printStackTrace();
}
}

@Override
protected TiledLayerModel initModel() throws Exception {
return new SCGISModel(location, spatialReference, fullExtent, tileInfo);
}

private void init() {
try {
tileInfo = new k();
tileInfo.f = new Point(-180, 90);


tileInfo.a = 256;
tileInfo.b = 256;
tileInfo.h = new ArrayList();

double resolution = 0.010998662747496;
double scale=4622333.68;
for (int j = 0, jcount = 11; j int level = j;
tileInfo.h.add(new AgsLOD(level, scale, resolution));
resolution/=2;
scale/=2;
}
} catch (Exception e) {
e.printStackTrace();
}
}

}

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