Here's a code snipped that shows how to copy the db from the asset
folder to phone memory:
private boolean copyDBfromAssets() throws Exception {
String destPath = "/data/data/" + context.getPackageName() + "/
databases";
String destPathFull = DB_PATH_PHONE + "/mydatabase";
InputStream input = null;
ZipInputStream zipInput = null;
FileOutputStream output = null;
try {
// open input
input = context.getAssets().open("database.zip");
zipInput = new ZipInputStream(input);
// create path & file & open output stream
File outPath = new File(destPath);
outPath.mkdirs();
File outFile = new File(destPathFull);
outFile.createNewFile();
output = new FileOutputStream( outFile );
// copy database
return copyFile(zipInput, output);
}
finally {
if (zipInput!=null) zipInput.close();
if (input!=null) input.close();
if (output!=null) output.close();
}
}
private boolean copyFile(InputStream in, FileOutputStream out) throws
IOException {
byte[] buffer = new byte[4096];
int bytesRead;
int sumBytesRead = 0;
while ((bytesRead = in.read(buffer))>0){
out.write(buffer, 0, bytesRead);
sumBytesRead += bytesRead;
}
out.flush();
return sync(out);
}
To keep the example short I removed all error handling code.
On Apr 27, 8:15 am, Javacoffee <[email protected]> wrote:
> Thanks guys for your kind reply :)
>
> On 4월27일, 오전11시32분, Emanuel Moecklin <[email protected]> wrote:
>
>
>
>
>
>
>
> > I'm running the database initialization in an IntentService which
> > always runs in a separate thread.
> > The main activity starts the service and connects to the service to
> > show a progress bar.
> > If the main activity is shut down the service continues to run.
> > If you restart the main activity it reconnects to the service and
> > shows the progress bar again.
> > The main difficulty with this approach is to prevent the service from
> > being started twice (IntentServices queue the Intents an run them
> > sequentially).
> > I solved this by checking & setting a SharedPreferences value that
> > indicates whether the initialization has finished or not. The Service
> > won't run if it has been previously started.
>
> > I guess that you load the database by sql inserts.
> > I used to do that too but a much faster solution is to include a
> > preloaded database in the asset folder and extract it to phone memory
> > during initialization.
> > This approach works fine if you extract to phone memory and not
> > sdcard. I used to do the latter too but sdcard seems to be too
> > unreliable on some phones and I got too many SQLException crash
> > reports so I reverted back to copying the db to phone memory.
> > One nice side effect of this approach is that the apk will be much
> > smaller (provided the asset database is zipped).
>
> > Cheers
> > Emanuel Moecklin
> > 1gravity LLC
>
> > On Apr 26, 2:37 am, Javacoffee <[email protected]> wrote:
>
> > > Hi guys,
>
> > > I'm implementing the app requires database set-up when installed for
> > > the first time.
>
> > > It works fine however it takes a couple of minutes wait with black
> > > screen (default screen) while establishing database.
>
> > > I understand that is necessary but would like to treat more elegant
> > > approach for User Interface.
>
> > > I'm using DatabaseHelper class inherited from SQLiteOpenHelper to
> > > initiate database for the first time.
>
> > > Here is snippet for your understanding.
>
> > > ================================================
> > > private static class DatabaseHelper extends SQLiteOpenHelper
>
> > > {
> > > private Context dbContext;
>
> > > DatabaseHelper(Context context)
> > > {
> > > super(context, DATABASE_NAME, null,
> > > DATABASE_VERSION);
> > > dbContext = context;
> > > }
>
> > > @Override
> > > public void onCreate(SQLiteDatabase db)
> > > {
> > > db.execSQL(DATABASE_CREATE);
> > > ContentValues values = new ContentValues();
> > > loadDB(db, values);
> > > }
>
> > > @Override
> > > public void onUpgrade(SQLiteDatabase db, int oldVersion,
> > > int
> > > newVersion)
> > > {
> > > Log.w(TAG, "Upgrading from " + oldVersion + " to
> > > " + newVersion);
> > > db.execSQL(DATABASE_DROP);
> > > onCreate(db);
> > > }
>
> > > private void loadDB(SQLiteDatabase db, ContentValues
> > > values)
> > > {
> > > // establishing database here.
> > > // it takes a couple of minutes but would like
> > > to handle with more elegant way.
> > > }
>
> > > }
>
> > > ====================================================================
>
> > > loadDB() method needs operation with more sophisticated approach so
> > > any idea or advise will be welcome.
>
> > > Thanks.- 원본 텍스트 숨기기 -
>
> > - 원본 텍스트 보기 -
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