Question

I have an android application that begins by downloading a large database to the sdcard (a little over 50mb) in an asynctask. The download code is as follows.

HttpURLConnection conexion = (HttpURLConnection) url.openConnection();
if(filePath.exists() && filePath.length() > 10000.00)
{
    downloaded = (int) filePath.length();
    conexion.setRequestProperty("Range", "bytes=" + (filePath.length()) + "-");
}
else
    conexion.setRequestProperty("Range", "bytes=" + downloaded + "-");

conexion.setDoInput(true);
conexion.setDoOutput(true);
conexion.setUseCaches(false);
conexion.connect();

…

try {
    totalFileLength = lengthOfFile + downloaded;
    progressDialog.setMax(lengthOfFile + downloaded);
    // downlod the file
    input = new BufferedInputStream(conexion.getInputStream());
    output = (downloaded==0)? new FileOutputStream(filePath): new FileOutputStream(filePath,true);
    bout = new BufferedOutputStream(output, 1024);

    byte data[] = new byte[1024];

    while ((count = input.read(data, 0, 1024)) >= 0 && running) {
        downloaded += count;
        // publishing the progress....
        //onProgressUpdate((int)(downloaded*100/lengthOfFile));
        progressDialog.setProgress(downloaded);
        bout.write(data, 0, count);
    }
} catch (Exception e) {
    ...
} finally {
    try {
        input.close();
        bout.flush();
        bout.close();
    } catch(IOException e) {
        ...
    }
}

After downloading the file completely I open the database and add a table to it.

try {
    myDbHelper.myDataBase.execSQL("CREATE TABLE IF NOT EXISTS FAVORITES (_id integer primary key autoincrement, MushroomID INTEGER)");
    success = true;
} catch (SQLException sqle) {
    throw sqle;
}

Now, this code works wonderfully on every device I run it on, but several of my users are getting this error on the execSQL line. It seems like it is not working on the Samsung Galaxy SII alone (there hasn’t been a complaint and subsequent stacktrace with this error with any other phone) but I’m not entirely sure its just this phone.

java.lang.RuntimeException: Unable to start activity ComponentInfo{net.daleroy.fungifieldguide/net.daleroy.fungifieldguide.activities.FungiFieldGuide}: android.database.sqlite.SQLiteDatabaseCorruptException: database disk image is malformed: CREATE TABLE IF NOT EXISTS FAVORITES (_id integer primary key autoincrement, MushroomID INTEGER)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
       at android.app.ActivityThread.access$1500(ActivityThread.java:117)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:130)
       at android.app.ActivityThread.main(ActivityThread.java:3691)
       at java.lang.reflect.Method.invokeNative(Native Method)
       at java.lang.reflect.Method.invoke(Method.java:507)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665)
       at dalvik.system.NativeStart.main(Native Method)
Caused by: android.database.sqlite.SQLiteDatabaseCorruptException: database disk image is malformed: CREATE TABLE IF NOT EXISTS FAVORITES (_id integer primary key autoincrement, MushroomID INTEGER)
       at android.database.sqlite.SQLiteDatabase.native_execSQL(Native Method)
       at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1904)
       at net.daleroy.fungifieldguide.services.MushroomService.MakeFavoriteTable(MushroomService.java:118)
       at net.daleroy.fungifieldguide.services.MushroomService.OpenDB(MushroomService.java:64)
       at net.daleroy.fungifieldguide.activities.FungiFieldGuide.onCreate(FungiFieldGuide.java:73)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)

I’ve received a copy of the database downloaded from a user with a sgs2 and the checksum of the file is off. I also cannot see any data or data structure in the file when I open with sqlite manager (firefox plugin). I let him download a copy of the database directly and place it in his data folder and the application works fine. So the problem is somewhere in the download process.

Answer 1

Starting from the API level 9 (Android 2.3) you can use DownloadManager to handle long-running HTTP downloads:

The download manager is a system service that handles long-running
HTTP downloads. Clients may request that a URI be downloaded to a
particular destination file. The download manager will conduct the
download in the background, taking care of HTTP interactions and
retrying downloads after failures or across connectivity changes and
system reboots.

Here is the example project which demonstrates DownloadManager usage: Android DownloadManager Example.

I think you can even try to backport DownloadManager to the previous Android versions (if you need to support them). Its source code can be found here: DownloadManager.java