How to display specific data from a sqlite database in a listview with a condition like 'where'? - database

Question

I made an application with an SQLite database. I want to show the data in a listview, but I don't want to show all the data from the database, but just some data. So, I want to add a condition. I only want to show the data where string 'dag' is 'maandag'.
Can anyone help me?
This is the code from my DatabaseHelper, where the database is created:
package com.persoonlijk.rooster.test2;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteStatement;
import java.util.ArrayList;
import java.util.List;
//A helper class to manage database creation and version management.
public class DataManipulator
{
//Database attributes
private static final String DATABASE_NAME = "mydatabase.db";
static final String TABLE_NAME = null;
private static final int DATABASE_VERSION = 12;
//Table attributes
public static final String KEY_ROWID = "id";
public static final String KEY_DAG = "dag";
public static final String KEY_UUR = "uur";
public static final String KEY_VAK = "vak";
public static final String KEY_LOKAAL = "lokaal";
private static Context context;
static SQLiteDatabase db;
private SQLiteStatement insertStmt;
private static final String INSERT = "insert into " + TABLE_NAME + " (dag,uur,vak,lokaal) values (?,?,?,?)";
public DataManipulator(Context context) {
DataManipulator.context = context;
OpenHelper openHelper = new OpenHelper(DataManipulator.context);
DataManipulator.db = openHelper.getWritableDatabase();
this.insertStmt = DataManipulator.db.compileStatement(INSERT);
}
public long insert(String dag,String uur,String vak,String lokaal) {
this.insertStmt.bindString(1, dag);
this.insertStmt.bindString(2, uur);
this.insertStmt.bindString(3, vak);
this.insertStmt.bindString(4, lokaal);
return this.insertStmt.executeInsert();
}
public void deleteAll() {
db.delete(TABLE_NAME, null, null);
}
public List<String[]> selectAll()
{
List<String[]> list = new ArrayList<String[]>();
Cursor cursor = db.query(TABLE_NAME, new String[] { "id","dag","uur","vak","lokaal" }, null, null, null, null, "dag asc");
int x=0;
if (cursor.moveToFirst()) {
do {
String[] b1=new String[]{cursor.getString(0),cursor.getString(1),cursor.getString(2),
cursor.getString(3),cursor.getString(4)};
list.add(b1);
x=x+1;
} while (cursor.moveToNext());
}
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}
cursor.close();
return list;
}
public boolean delete(long id) {
return db.delete(TABLE_NAME, KEY_ROWID + "=" + id, null) > 0;
}
private static class OpenHelper extends SQLiteOpenHelper {
OpenHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_NAME + " (id INTEGER PRIMARY KEY, dag TEXT, uur TEXT, vak TEXT, lokaal TEXT)");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
}
}
This is the code from the Activity where I want to display the specific data. Right now, all the data from the database is displayed.
package com.persoonlijk.rooster.test2;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class RoosterMaandag extends ListActivity{
TextView selection;
public int idToModify;
DataManipulator dm;
List<String[]> list = new ArrayList<String[]>();
List<String[]> names2 =null ;
String[] stg1;
/** Called when the activity is first created. */
//zorgt voor het overzicht van de gegevens uit de database
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.rooster);
dm = new DataManipulator(this);
names2 = dm.selectAll();
stg1=new String[names2.size()];
int x=0;
String stg;
for (String[] dag : names2) {
stg = dag[1]+" - "+dag[2]+ " - "+dag[3]+" - "+dag[4];
stg1[x]=stg;
x++;
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,stg1);
this.setListAdapter(adapter);
selection=(TextView)findViewById(R.id.selection);
}
//menuknoppen
#Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(Menu.NONE, 0, 0, "Voeg gegevens toe");
menu.add(Menu.NONE, 1, 1, "Verwijder gegevens");
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case 0:
startActivity(new Intent(this, SaveData.class));
return true;
case 1:
startActivity(new Intent(this, VerwijderData.class));
return true;
}
return false;
}
}
Please let me know when my question isn't clear enough. I really hope someone can help me!
I added this code in my DataManipulator.java:
public List<String[]> selectSome(String arg) {
String[] columns = new String[] { "id", "dag", "uur", "vak", "lokaal" };
String[] selectionArgs = {arg};
Cursor cursor = db.query(TABLE_NAME, columns, "dag = ?", selectionArgs, null, null, "dag asc");
List<String[]> list = new ArrayList<String[]>(cursor.getCount());
while (cursor.moveToNext()) {
String[] b1 = new String[] { cursor.getString(0),
cursor.getString(1), cursor.getString(2),
cursor.getString(3), cursor.getString(4) };
list.add(b1);
}
cursor.close();
return list;
}
and this code in my RoosterMaandag.java:
public void onCreate(Bundle savedInstanceState){
....
dm.selectSome("maandag");
....
}

Answer 1

I don't know about android but for sql
try this
select data_to_print from table_name where REGEXP_LIKE(column_name_where_to_match,'dag$');
more info here http://docs.oracle.com/cd/B12037_01/server.101/b10759/ap_posix001.htm#i690819
Example:
SQL> select job_id from jobs where regexp_like(job_id,'N$');
JOB_ID
----------
MK_MAN
PU_MAN
SA_MAN
ST_MAN

Answer 2

you need a new method in your DataManipulator class:
public List<String[]> selectSome(String arg) {
String[] columns = new String[] { "id", "dag", "uur", "vak", "lokaal" };
String[] selectionArgs = {arg};
Cursor cursor = db.query(TABLE_NAME, columns, "dag = ?", selectionArgs, null, null, "dag asc");
List<String[]> list = new ArrayList<String[]>(cursor.getCount());
while (cursor.moveToNext()) {
String[] b1 = new String[] { cursor.getString(0),
cursor.getString(1), cursor.getString(2),
cursor.getString(3), cursor.getString(4) };
list.add(b1);
}
cursor.close();
return list;
}
I'll say it again. consider using a CursorAdapter for these tasks.