Saving Android Database to SD card?

Question

I am attempting to export a database that I am creating to the SD card of my phone so that I can look at its contents in DDMS mode of eclipse.

The following code is from the question: Making a database backup to SDCard on Android

However, I am unsure how to use this code within my application? I.e. do I need to instantiate the class? And if so, where?

package com.example.multapply;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Environment;
import android.util.Log;
import android.widget.Toast;

public class ExportDatabaseFileTask extends AsyncTask<String, Void, Boolean> {

    //Default constructor
    public ExportDatabaseFileTask() {

    }

    //delete if necessary
    private final ProgressDialog dialog = new ProgressDialog(null);


    // can use UI thread here
    protected void onPreExecute() {
        this.dialog.setMessage("Exporting database...");
        this.dialog.show();
    }

    // automatically done on worker thread (separate from UI thread)
    protected Boolean doInBackground(final String... args) {

        //original database file location
        File dbFile = new File(Environment.getDataDirectory()
                + "/data/com.example.multapply/databases/MultapplyDatabase.db");

        //the destination file location
        File exportDir = new File(Environment.getExternalStorageDirectory(), "");
        if (!exportDir.exists()) {
            exportDir.mkdirs();
        }


        File file = new File(exportDir, dbFile.getName());
        try {
            file.createNewFile();
            this.copyFile(dbFile, file);
            return true;
        } catch (IOException e) {
            Log.e("mypck", e.getMessage(), e);
            return false;
        }
    }

    // can use UI thread here
    protected void onPostExecute(final Boolean success) {
        if (this.dialog.isShowing()) {
            this.dialog.dismiss();
        }
        if (success) {
            Toast.makeText( null, "Export successful!", Toast.LENGTH_SHORT)
                    .show();
        } else {
            Toast.makeText(null, "Export failed", Toast.LENGTH_SHORT).show();
        }
    }

    void copyFile(File src, File dst) throws IOException {
        FileChannel inChannel = new FileInputStream(src).getChannel();
        FileChannel outChannel = new FileOutputStream(dst).getChannel();
        try {
            inChannel.transferTo(0, inChannel.size(), outChannel);
        } finally {
            if (inChannel != null)
                inChannel.close();
            if (outChannel != null)
                outChannel.close();
        }
    }

}

Edit (my current code for adding to the database):

//Adding the score to the database from 

DatabaseHelper db = new DatabaseHelper(this);

db.addScore(new Score(UserName.getUserName(), score, System.currentTimeMillis() ));

Is the progressDialog and Toast even necessary in order to make the backup? — RYJava2014, Jul 14 '14 at 18:41

score 0 · Accepted Answer · answered Jul 14 '14 at 18:32

0

it is an AsyncTask, so you just have to instantieate a class and call it whenever you want to do the backup:

ExportDatabaseFileTask task = new ExportDatabaseFileTask();
task.execute();

The onPostExecute() will try to show a Toast, so you would need to call the backup from an Activity (or remove those Toasts).

answered Jul 14 '14 at 18:32

Mikel Pascual

2,202
18
27

Thanks, can you please see my latest edit at the bottom, Would I just call the code you specified after that code? – RYJava2014 Jul 14 '14 at 18:43
Yes, that could be right. They only thing that could fail, as I told you, are those calls to Toast...show() if you call this from outside an Activity; but you could just remove the Toasts. – Mikel Pascual Jul 14 '14 at 18:45
By the way, you should accept the answer, as it already answers your question. – Mikel Pascual Jul 14 '14 at 18:47
Also, where would the file then be saved? I.e. where would i find it in DDMS? – RYJava2014 Jul 14 '14 at 18:47
Your question was already answered. Now you just want someone to explain all the code for you. That's not the point. – Mikel Pascual Jul 14 '14 at 18:49

Saving Android Database to SD card?

1 Answers1