ฉันทำแผนที่ออฟไลน์โดยใช้ ESRI Android SDK และเลเยอร์ไทล์ที่กำหนดเอง ฉันใช้เซิร์ฟเวอร์ ArcGIS เพื่อสร้างการแคชแผนที่ที่ใช้ไทล์จากนั้นแทรกไทล์เหล่านั้นลงในฐานข้อมูล SQLite และทำการสืบค้นจากแถวและคอลัมน์จากที่นั่น มันใช้งานได้ดีและถ้าคุณต้องการแผนที่ที่กำหนดเองตั้งแต่ต้นจนจบมันเป็นวิธีที่ใช้งานได้ดีมาก
package com.main.utilinspect;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.List;
import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonParser;
import android.content.Context;
import android.util.Log;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import com.esri.core.internal.c.d;
import com.esri.core.internal.c.h;
import com.esri.core.internal.c.l;
import com.esri.android.map.TiledServiceLayer;
public class OfflineDbTiledLayer extends TiledServiceLayer {
File workingDirectory;
String mapDefinition;
String databaseName;
private SQLiteDatabase database;
File blankImage;
byte[] blankImageBytes;
private final Object lock = new Object();
private static final String TAG = "OfflineTiledLayer";
public OfflineDbTiledLayer(Context paramContext, File workingDirectory, String mapDefinition, String databaseName) {
super("required");
this.workingDirectory = workingDirectory;
this.mapDefinition = mapDefinition;
this.databaseName = databaseName;
String databasePath = workingDirectory.getAbsolutePath() + File.separator + databaseName;
this.database = SQLiteDatabase.openDatabase(databasePath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS);
this.blankImage = new File(workingDirectory.getAbsolutePath() + File.separator + "blank.png");
RandomAccessFile raFile = null;
try {
raFile = new RandomAccessFile(this.blankImage, "r");
blankImageBytes = new byte[(int) raFile.length()];
raFile.readFully(blankImageBytes);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
if(raFile != null) {
try {
raFile.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
h h1 = null;
try
{
JsonParser paramJsonParser = new JsonFactory()
.createJsonParser(new File(workingDirectory.getAbsolutePath() + File.separator + mapDefinition));
paramJsonParser.nextToken();
h1 = h.a(paramJsonParser, "test");
}
catch(Exception ex){
}
setFullExtent(h1.f());
setDefaultSpatialReference(h1.c());
setInitialExtent(h1.e());
l l1;
List list;
int i;
double ad[] = new double[i = (list = (l1 = h1.d()).h).size()];
double ad1[] = new double[i];
for(int j = 0; j < list.size(); j++)
{
ad[j] = ((d)list.get(j)).b();
ad1[j] = ((d)list.get(j)).a();
}
setTileInfo(new com.esri.android.map.TiledServiceLayer.TileInfo(l1.f, ad, ad1, i, l1.c, l1.b, l1.a));
super.initLayer();
return;
}
private void openDatabase(){
if(!database.isOpen()){
String databasePath = workingDirectory.getAbsolutePath() + File.separator + databaseName;
this.database = SQLiteDatabase.openDatabase(databasePath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS);
}
}
private void closeDatabase(){
if(database.isOpen()){
this.database.close();
}
}
@Override
protected byte[] getTile(int level, int column, int row) throws Exception {
byte[] tileImage;
Log.i(TAG, "getTile");
Log.i(TAG, "getTile - retrieving tile");
synchronized(lock) {
Log.i(TAG, "getTile - entered synchronized block");
openDatabase();
// First check to see if the tile exists in the database
Cursor tileCursor = database.rawQuery("SELECT image FROM tiles WHERE level = " + Integer.toString(level) + " AND row = " + Integer.toString(row) + " AND column = " + Integer.toString(column), null);
if(tileCursor != null && tileCursor.getCount() > 0) {
tileCursor.moveToFirst();
tileImage = tileCursor.getBlob(0);
Log.i(TAG, "getTile - tile found, returning image");
}
else {
// The tile does not exist in the database, read the blank placeholder tile and serve it
tileImage = blankImageBytes;
Log.i(TAG, "getTile - tile not found returning blank");
}
tileCursor.close();
this.database.close();
}
Log.i(TAG, "getTile - exited synchronized block");
return tileImage;
}
}