sqllite and populating list view, android
- by Rob Bushway
I am populating a text and list view from a sqllite database. The data is populating from the cursor correctly (I see the list filling with text rows), but I'm not able to see the actual text in the rows - all I see are empty rows. For the life of me, I can't figure out what I'm not able to see the data in the text rows.
My layouts:
Tab layout:
list layout:
row layout:
<?xml version="1.0" encoding="utf-8"?>
/
My topics activity
package com.gotquestions.gqapp;
import com.gotquestions.gqapp.R.layout;
import android.R;
import android.app.ListActivity;
import android.database.Cursor;
import android.database.SQLException;
import android.os.Bundle;
import android.widget.SimpleCursorAdapter;
public class TopicsActivity extends ListActivity {
private DataBaseHelper myDbHelper;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//
DataBaseHelper myDbHelper = new DataBaseHelper(this);
myDbHelper = new DataBaseHelper(this);
//test
try {
myDbHelper.openDataBase();
}catch(SQLException sqle){
throw sqle;
}
setContentView(layout.list_layout);
Cursor c = myDbHelper.fetchAllTopics();
startManagingCursor(c);
String[] from = new String[] { DataBaseHelper.KEY_TITLE };
int[] to = new int[] { R.id.text1 };
// Now create an array adapter and set it to display using our row
SimpleCursorAdapter notes =
new SimpleCursorAdapter(this, layout.notes_row, c, from, to);
setListAdapter(notes);
myDbHelper.close();
}
}
My database helper:
package com.gotquestions.gqapp;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DataBaseHelper extends SQLiteOpenHelper{
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.gotquestions.gqapp/databases/";
private static String DB_NAME = "gotquestions_database.mp3";
public static final String KEY_TITLE = "topic_title";
public static final String KEY_ARTICLE_TITLE = "article_title";
public static final String KEY_ROWID = "_id";
private static final String TAG = null;
private SQLiteDatabase myDataBase;
//
private final Context myContext;
/**
* Constructor
* Takes and keeps a reference of the passed context in order to access to the application assets and resources.
* @param context
*/
public DataBaseHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
/**
* Creates a empty database on the system and rewrites it with your own database.
* */
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion)
{
Log.w(TAG, "Upgrading database from version " + oldVersion
+ " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS titles");
onCreate(db);
}
public Cursor getTitle(long rowId) throws SQLException
{
Cursor mCursor =
myDataBase.query(true, "topics", new String[] {
KEY_ROWID,
KEY_TITLE
},
KEY_ROWID + "=" + rowId,
null,
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
public Cursor fetchAllTopics() {
return myDataBase.query("topics", new String[] {KEY_ROWID, KEY_TITLE},
null,
null,
null,
null,
null);
};
public Cursor fetchAllFavorites() {
return myDataBase.query("articles", new String[] {
KEY_ROWID,
KEY_ARTICLE_TITLE},
null,
null,
null,
null,
null);
};
}
