Step By Step 簡易Mapsforge App開發：EnvCheck

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目標Achievements

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這個類別的工作是去偵測使用者是否有我們所需的地圖資料，若有那就去偵測是否有新的版本，否則就去下載。這個類別還做了一件事就是將圖資進行渲染(為了讓圖資檔案比較小，所以使用了向量圖的儲存方式)並喂給MapView去做顯示。

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程式碼Code

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package lien.ching.maptracker.api;

import android.app.Activity;
import android.app.DownloadManager;
import android.app.ProgressDialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Environment;
import android.util.Log;
import android.widget.Toast;

import org.mapsforge.map.android.graphics.AndroidGraphicFactory;
import org.mapsforge.map.android.util.AndroidUtil;
import org.mapsforge.map.android.view.MapView;
import org.mapsforge.map.layer.cache.TileCache;
import org.mapsforge.map.layer.labels.LabelLayer;
import org.mapsforge.map.layer.renderer.TileRendererLayer;
import org.mapsforge.map.reader.MapFile;
import org.mapsforge.map.rendertheme.InternalRenderTheme;

import java.io.File;
import java.util.concurrent.TimeUnit;

import lien.ching.maptracker.Constant;
import lien.ching.maptracker.R;
import lien.ching.maptracker.overlay.NowLocationLayout;

/**
 * Created by lienching on 11/27/15.
 * This class is use for checking if the device have the required map file or not.
 */
public class EnvCheck {
    private Context context;
    private String externalpath = Environment.getExternalStorageDirectory().getPath();
    private MapDownloadManager mapDownloadManager;
    private MapUpdateManager mapUpdateManager;
    private mapDownloadManager downloadManger;
    private Activity activity;
    private MapView mapView;
    private NowLocationLayout locationLayout;
    public EnvCheck(MapView mapView,NowLocationLayout locationLayout,Context context,Activity activity){
        this.activity = activity;
        this.context = context;
        this.mapView = mapView;
        this.locationLayout = locationLayout;
    }
    public EnvCheck(Context context,Activity activity){
        this.activity = activity;
        this.context = context;
        this.mapView = null;
    }

    public void CheckAndDownload(String continent, String sourcefile) {
        String mapfile = continent+"/"+sourcefile;
        if(!this.isMapResourceExist(mapfile)) {
            downloadManger = new mapDownloadManager(mapView,locationLayout, context, mapfile);
            Thread thread = new Thread(downloadManger);
            thread.run();
        }
        else{
            MapFile targetFile = new MapFile(new File(Constant.PATH_MAPSFORGE+mapfile));
            TileCache tileCache = AndroidUtil.createTileCache(context, "mapcache", mapView.getModel().displayModel.getTileSize(), 1f, mapView.getModel().frameBufferModel.getOverdrawFactor());
            TileRendererLayer tileRendererLayer = AndroidUtil.createTileRendererLayer(tileCache,mapView.getModel().mapViewPosition,targetFile, InternalRenderTheme.OSMARENDER,true,true);
            tileRendererLayer.setXmlRenderTheme(InternalRenderTheme.OSMARENDER);
            mapView.getLayerManager().getLayers().add(tileRendererLayer);
        }
    }


    public boolean isMapResourceDirExist(final String continent){
        File dir = new File(Constant.PATH_MAPSFORGE+continent);
        if(!dir.exists()) {
            if (!dir.mkdirs()) {
                Log.e("EnvCheck","Dir create failed");
                return false;
            }
            Log.d("EnvCheck","Dir Create Sucess!");
        }
        return true;
    }
    public boolean isMapResourceExist(final String mapfile){
        if(!(new File(externalpath+"/mapsforge").exists()))
            createDirectory();
        File searchFile = new File(externalpath+"/mapsforge/maps/"+mapfile);
        if(searchFile.exists())
            return true;
        return false;
    }

    public void createDirectory(){
        File target = new File(externalpath+"/mapsforge/maps");
        target.mkdirs();
        if(target.exists()&&target.isDirectory()){
            Toast.makeText(context, R.string.toast_dir_success, Toast.LENGTH_SHORT).show();
        }
        else{
            Toast.makeText(context, R.string.toast_dir_fail_retry,Toast.LENGTH_SHORT).show();
            target.mkdir();
            if(target.exists()&&target.isDirectory()){
                Toast.makeText(context, R.string.toast_dir_success, Toast.LENGTH_SHORT).show();
            }
            else{
                Toast.makeText(context, R.string.toast_dir_fail, Toast.LENGTH_SHORT).show();
            }
        }
    }
}

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說明Explanation

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第64行：建立圖資渲染暫存區，For Detail 第65~66行： 建立圖資圖層並設定地圖風格