dimanche 29 mars 2015

Data not being displayed in a listview from SQLite in android

I have successfully created a database and inserted data into it.However when retrieving the data and displaying it in a listview ,the data is not being displayed.I am unsure as to where my problem lies.I have researched in S/O and other tutorials but cannot seem to find what suits my code.The following is what i have tried:


DBHelper.java which extends SQLiteOpenHelper





public class DBHelper extends SQLiteOpenHelper {

public static final String DATABASE_NAME = "MyDBName.db";
public static final String CONTACTS_TABLE_NAME = "contacts";
public static final String CONTACTS_COLUMN_ID = "id";
public static final String CONTACTS_COLUMN_NAME = "name";
public static final String CONTACTS_COLUMN_EMAIL = "email";
public static final String CONTACTS_COLUMN_PHONE = "phone";

private HashMap hp;

public DBHelper(Context context)
{
super(context, DATABASE_NAME , null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(
"create table contacts " +
"(id integer primary key, title text,phone text,email text)"
);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS contacts");
onCreate(db);
}

public boolean insertContact (String name, String phone, String email)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();

contentValues.put("title", name);
contentValues.put("amount", phone);
contentValues.put("description", email);


db.insert("contacts", null, contentValues);
return true;
}
public Cursor getData(int id){
SQLiteDatabase db = this.getReadableDatabase();
Cursor res = db.rawQuery( "select * from contacts where id="+id+"", null );
return res;
}
public int numberOfRows(){
SQLiteDatabase db = this.getReadableDatabase();
int numRows = (int) DatabaseUtils.queryNumEntries(db, CONTACTS_TABLE_NAME);
return numRows;
}
public boolean updateContact (Integer id, String name, String phone, String email)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("title", name);
contentValues.put("amount", phone);
contentValues.put("description", email);

db.update("contacts", contentValues, "id = ? ", new String[] { Integer.toString(id) } );
return true;
}

public Integer deleteContact (Integer id)
{
SQLiteDatabase db = this.getWritableDatabase();
return db.delete("contacts",
"id = ? ",
new String[] { Integer.toString(id) });
}
public ArrayList getAllContacts()
{
ArrayList array_list = new ArrayList();
//hp = new HashMap();
SQLiteDatabase db = this.getReadableDatabase();
Cursor res = db.rawQuery( "select * from contacts", null );
res.moveToFirst();
while(res.isAfterLast() == false){
array_list.add(res.getString(res.getColumnIndex(CONTACTS_COLUMN_NAME)));
res.moveToNext();
}
return array_list;
}
}



In Details.java where i insert the data on button click this way:





public void run(View view) {
Bundle extras = getIntent().getExtras();
if (extras != null) {
int Value = extras.getInt("id");
if (Value > 0) {
if (mydb.updateContact(id_To_Update, title.getText().toString(), amount.getText().toString(), description.getText().toString())) {
Toast.makeText(getApplicationContext(), "Updated", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(getApplicationContext(), MyBasket.class);
startActivity(intent);
} else {
Toast.makeText(getApplicationContext(), "Not Updated", Toast.LENGTH_SHORT).show();
}
} else {
if (mydb.insertContact(title.getText().toString(), amount.getText().toString(), description.getText().toString())) {
showAlertDialog();
} else {
Toast.makeText(getApplicationContext(), "not done", Toast.LENGTH_SHORT).show();
}

}
}
}



MyBasket.java is where i display the listview of the data added this way: in my OnCreate()





mydb = new DBHelper(this);

ArrayList array_list = mydb.getAllContacts();

ArrayAdapter arrayAdapter =
new ArrayAdapter(this,android.R.layout.simple_list_item_1, array_list);

//adding it to the list view.
obj = (ListView)findViewById(R.id.listView1);
obj.setAdapter(arrayAdapter);



Still i am unable to display.I dont know where i am going wrong.Any help or suggestions will be much apprecated.


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