Apps SQLite Database Version via xml file

[ondrovic]

I am storing a pre-created database file and an xml file in my dropbox ( for storage ) I would like to be able to read the xml file and if the version is different download the new database file and replace it on the sd card. Can anyone point me in the right direction?

 

[alostpacket]

That's a lot of stuff to explain/code, which part do you need help on?

I'd start by breaking it down to smaller tasks. Say, just work on the downloading of any old file first. Then download and parse the XML.

I wouldn't even worry about databases until you get those two things done

 

[ondrovic]

Sorry I already have the database portion done along with the downloading of the database file. I guess I need help with the version control via a xml file.

I would like to add a check to the CheckDB() which parses the xml file and if the version number is different then download and replace the database

Downloader.java

package com.ondrovic.downloader;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Intent;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;

public class Downloader extends Activity {
    SQLiteDatabase db = null;
    public static final String LOG_TAG = "DOWNLOADER";
    private ProgressDialog bar;
    public static final int PROGRESS = 0;
    
    File rDIR = Environment.getExternalStorageDirectory();
    
    public String fDIR = "/data/databases/boombozz/";
    public String fNAME = "boombozz.db";
    public String fURL = "http://db.tt/PTb0KMJK";
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        
        super.onCreate(savedInstanceState);
        
        checkDB();
        
        
            //DIRExists(fDIR);
            //new Download().execute(fURL);
    }
    
    class Download extends AsyncTask <String, String, String> {
        
        @Override
        public void onPreExecute() {
            super.onPreExecute();
            showDialog(PROGRESS);
        }
        
        @Override
        protected String doInBackground(String... aurl) {
            
            try {
                URL url = new URL(fURL);
                HttpURLConnection con = (HttpURLConnection) url.openConnection();
                con.setRequestMethod("GET");
                con.setDoOutput(true);
                con.connect();
                
                int fSIZE = con.getContentLength();
                
                FileOutputStream out = new FileOutputStream(new File(rDIR + fDIR, fNAME));
                
                InputStream in = con.getInputStream();
                
                byte[] buffer = new byte[1024];
                int len = 0;
                long total = 0;
                
                while ((len = in.read(buffer)) > 0) {
                    total += len;
                    publishProgress("" + (int)((total*100)/fSIZE));
                    out.write(buffer, 0, len);
                }
                out.close();
            } catch (Exception e) {
                Log.d(LOG_TAG, e.getMessage());
            }
            
            return null;
        }
        
        protected void onProgressUpdate(String... progress) {
            
            Log.d(LOG_TAG, progress[0]);
            bar.setProgress(Integer.parseInt(progress[0]));
        }
        
        @Override
        protected void onPostExecute(String unused) {
            
            dismissDialog(PROGRESS);
            startActivity(new Intent(getApplicationContext(), Main.class));
            Downloader.this.finish();
        }
    }
    
    public void DIRExists(String dirName) {
        
        File nDIR = new File(rDIR + dirName);
        if (!nDIR.exists()) {
            nDIR.mkdirs();
        }
    }
    
    private boolean checkDB() {
        
        try {
            
            db = SQLiteDatabase.openDatabase(rDIR + fDIR + fNAME, null,
                    SQLiteDatabase.OPEN_READONLY);
            db.close();
            startActivity(new Intent(getApplicationContext(), Main.class));
            Downloader.this.finish();
        } catch (SQLException sqle) {
            Log.d(LOG_TAG, sqle.getMessage());
            DIRExists(fDIR);
            new Download().execute(fURL);
        }
        
        return db != null;
    }
    
    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
        case PROGRESS:
            bar = new ProgressDialog(this);
            bar.setTitle("Database");
            bar.setMessage("Downloading database...");
            bar.setIndeterminate(false);
            bar.setMax(100);
            bar.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            bar.setCancelable(false);
            bar.show();
            
            return bar;
        default:
            return null;
        }
    }
}

 

[alostpacket]

So is the only purpose of the XML file to hold the db version number? If so I would use a flat text file. XML is not worth the effort.

 

[ondrovic]

Yes pretty much. Since I am not creating the database in code I want to be able to make changes to it and have the app check.

Would you happen to have an example or could you point me in the right direction on how to accomplish this?

Thanks