How to save/retrieve words to/from SQlite database?
- by user998032
Sorry if I repeat my question but I have still had no clues of what to do and how to deal with the question.
My app is a dictionary. I assume that users will need to add words that they want to memorise to a Favourite list. Thus, I created a Favorite button that works on two phases:
short-click to save the currently-view word into the Favourite list;
and long-click to view the Favourite list so that users can click on any words to look them up again.
I go for using a SQlite database to store the favourite words but I wonder how I can do this task. Specifically, my questions are:
Should I use the current dictionary SQLite database or create a new SQLite database to favorite words?
In each case, what codes do I have to write to cope with the mentioned task?
Could anyone there kindly help?
Here is the dictionary code:
package mydict.app;
import java.util.ArrayList;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.util.Log;
public class DictionaryEngine {
static final private String SQL_TAG = "[MyAppName - DictionaryEngine]";
private SQLiteDatabase mDB = null;
private String mDBName;
private String mDBPath;
//private String mDBExtension;
public ArrayList<String> lstCurrentWord = null;
public ArrayList<String> lstCurrentContent = null;
//public ArrayAdapter<String> adapter = null;
public DictionaryEngine()
{
lstCurrentContent = new ArrayList<String>();
lstCurrentWord = new ArrayList<String>();
}
public DictionaryEngine(String basePath, String dbName, String dbExtension)
{
//mDBExtension = getResources().getString(R.string.dbExtension);
//mDBExtension = dbExtension;
lstCurrentContent = new ArrayList<String>();
lstCurrentWord = new ArrayList<String>();
this.setDatabaseFile(basePath, dbName, dbExtension);
}
public boolean setDatabaseFile(String basePath, String dbName, String dbExtension)
{
if (mDB != null)
{
if (mDB.isOpen() == true) // Database is already opened
{
if (basePath.equals(mDBPath) && dbName.equals(mDBName)) // the opened database has the same name and path -> do nothing
{
Log.i(SQL_TAG, "Database is already opened!");
return true;
}
else
{
mDB.close();
}
}
}
String fullDbPath="";
try
{
fullDbPath = basePath + dbName + "/" + dbName + dbExtension;
mDB = SQLiteDatabase.openDatabase(fullDbPath, null, SQLiteDatabase.OPEN_READWRITE|SQLiteDatabase.NO_LOCALIZED_COLLATORS);
}
catch (SQLiteException ex)
{
ex.printStackTrace();
Log.i(SQL_TAG, "There is no valid dictionary database " + dbName +" at path " + basePath);
return false;
}
if (mDB == null)
{
return false;
}
this.mDBName = dbName;
this.mDBPath = basePath;
Log.i(SQL_TAG,"Database " + dbName + " is opened!");
return true;
}
public void getWordList(String word)
{
String query;
// encode input
String wordEncode = Utility.encodeContent(word);
if (word.equals("") || word == null)
{
query = "SELECT id,word FROM " + mDBName + " LIMIT 0,15" ;
}
else
{
query = "SELECT id,word FROM " + mDBName + " WHERE word >= '"+wordEncode+"' LIMIT 0,15";
}
//Log.i(SQL_TAG, "query = " + query);
Cursor result = mDB.rawQuery(query,null);
int indexWordColumn = result.getColumnIndex("Word");
int indexContentColumn = result.getColumnIndex("Content");
if (result != null)
{
int countRow=result.getCount();
Log.i(SQL_TAG, "countRow = " + countRow);
lstCurrentWord.clear();
lstCurrentContent.clear();
if (countRow >= 1)
{
result.moveToFirst();
String strWord = Utility.decodeContent(result.getString(indexWordColumn));
String strContent = Utility.decodeContent(result.getString(indexContentColumn));
lstCurrentWord.add(0,strWord);
lstCurrentContent.add(0,strContent);
int i = 0;
while (result.moveToNext())
{
strWord = Utility.decodeContent(result.getString(indexWordColumn));
strContent = Utility.decodeContent(result.getString(indexContentColumn));
lstCurrentWord.add(i,strWord);
lstCurrentContent.add(i,strContent);
i++;
}
}
result.close();
}
}
public Cursor getCursorWordList(String word)
{
String query;
// encode input
String wordEncode = Utility.encodeContent(word);
if (word.equals("") || word == null)
{
query = "SELECT id,word FROM " + mDBName + " LIMIT 0,15" ;
}
else
{
query = "SELECT id,content,word FROM " + mDBName + " WHERE word >= '"+wordEncode+"' LIMIT 0,15";
}
//Log.i(SQL_TAG, "query = " + query);
Cursor result = mDB.rawQuery(query,null);
return result;
}
public Cursor getCursorContentFromId(int wordId)
{
String query;
// encode input
if (wordId <= 0)
{
return null;
}
else
{
query = "SELECT id,content,word FROM " + mDBName + " WHERE Id = " + wordId ;
}
//Log.i(SQL_TAG, "query = " + query);
Cursor result = mDB.rawQuery(query,null);
return result;
}
public Cursor getCursorContentFromWord(String word)
{
String query;
// encode input
if (word == null || word.equals(""))
{
return null;
}
else
{
query = "SELECT id,content,word FROM " + mDBName + " WHERE word = '" + word + "' LIMIT 0,1";
}
//Log.i(SQL_TAG, "query = " + query);
Cursor result = mDB.rawQuery(query,null);
return result;
}
public void closeDatabase()
{
mDB.close();
}
public boolean isOpen()
{
return mDB.isOpen();
}
public boolean isReadOnly()
{
return mDB.isReadOnly();
}
}
And here is the code below the Favourite button to save to and load the Favourite list:
btnAddFavourite = (ImageButton) findViewById(R.id.btnAddFavourite);
btnAddFavourite.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Add code here to save the favourite, e.g. in the db.
Toast toast = Toast.makeText(ContentView.this, R.string.messageWordAddedToFarvourite, Toast.LENGTH_SHORT);
toast.show();
}
});
btnAddFavourite.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
// Open the favourite Activity, which in turn will fetch the saved favourites, to show them.
Intent intent = new Intent(getApplicationContext(), FavViewFavourite.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getApplicationContext().startActivity(intent);
return false;
}
});
}
