I'm writting my own android app for storing contacts (name, phone number, email). I've got a database, two activity, one for displaying the list of contacts and the other for filling a form with a contact data. The probleme is that I don't know how to delete all conctacts from the list and also how to delete a single contact from the list. I will show you my code.
package com.example.contactsapp;
public class Contact {
//private variables
int _id;
String _name;
String _lastName;
String _phone_number;
String _email;
// Empty constructor
public Contact(){
}
// constructor
public Contact(int id, String name, String lastName, String _phone_number, String email){
this._id = id;
this._name = name;
this._lastName = lastName;
this._phone_number = _phone_number;
this._email = email;
}
// constructor
public Contact(String name, String lastName, String _phone_number, String email){
this._name = name;
this._lastName = lastName;
this._phone_number = _phone_number;
this._email = email;
}
// getting ID
public int getID(){
return this._id;
}
// setting id
public void setID(int id){
this._id = id;
}
// getting name
public String getName(){
return this._name;
}
// setting name
public void setName(String name){
this._name = name;
}
// getting lastName
public String getLastName(){
return this._lastName;
}
// setting lastName
public void setLastName(String lastName){
this._lastName = lastName;
}
// getting phone number
public String getPhoneNumber(){
return this._phone_number;
}
// setting phone number
public void setPhoneNumber(String phone_number){
this._phone_number = phone_number;
}
// getting lastName
public String getEmail(){
return this._email;
}
// setting lastName
public void setEmail(String email){
this._email = email;
}
}
package com.example.contactsapp;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "contactsManager";
// Contacts table name
private static final String TABLE_CONTACTS = "contacts";
// Contacts Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_LAST_NAME = "last_name";
private static final String KEY_PH_NO = "phone_number";
private static final String KEY_EMAIL = "email";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT," + KEY_LAST_NAME + " TEXT,"
+ KEY_PH_NO + " TEXT," + KEY_EMAIL + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
// Create tables again
onCreate(db);
}
/**
* All CRUD(Create, Read, Update, Delete) Operations
*/
// Adding new contact
public void addContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName()); // Contact Name
values.put(KEY_LAST_NAME, contact.getLastName()); // Contact Last Name
values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone
values.put(KEY_EMAIL, contact.getEmail()); // Contact Email
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
db.close(); // Closing database connection
}
// Getting single contact
Contact getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_LAST_NAME, KEY_PH_NO, KEY_EMAIL }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getString(4));
// return contact
return contact;
}
// Getting All Contacts
public List<Contact> getAllContacts() {
List<Contact> contactList = new ArrayList<Contact>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Contact contact = new Contact();
contact.setID(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setLastName(cursor.getString(2));
contact.setPhoneNumber(cursor.getString(3));
contact.setEmail(cursor.getString(4));
String name = cursor.getString(1) +"\n"+ cursor.getString(2) +"\n"+ cursor.getString(3) +"\n"+ cursor.getString(4);
MainActivity.ArrayofName.add(name);
// Adding contact to list
contactList.add(contact);
} while (cursor.moveToNext());
}
// return contact list
return contactList;
}
// Updating single contact
public int updateContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName());
values.put(KEY_LAST_NAME, contact.getLastName());
values.put(KEY_PH_NO, contact.getPhoneNumber());
values.put(KEY_EMAIL, contact.getEmail());
// updating row
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
}
//public void clearDataBase(SQLiteDatabase db) {
//db.execSQL("DROP TABLE " + TABLE_CONTACTS);
//onCreate(db);
//}
// Deleting single contact
public void deleteContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
db.close();
}
// Getting contacts Count
public int getContactsCount() {
String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
}
public class MainActivity extends Activity {
DatabaseHandler db = new DatabaseHandler(this);
private ListView listView;
public static ArrayList<String> ArrayofName = new ArrayList<String>();
//For menu
private Menu m = null;
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
MenuInflater inflater = getMenuInflater();
//R.menu.menu est l'id de notre menu
inflater.inflate(R.menu.menu, menu);
m = menu;
return true;
}
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db.getAllContacts();
listView = (ListView) findViewById(R.id.listView1);
registerForContextMenu(listView);
listView.setOnCreateContextMenuListener(this);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, ArrayofName);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
Toast.makeText(getApplicationContext(),
((TextView) v).getText(), Toast.LENGTH_SHORT).show();
//db.deleteContact();
}
});
}
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
}
//For menu
@Override
public boolean onOptionsItemSelected (MenuItem item)
{
final Context context = this;
switch(item.getItemId())
{
case R.id.item1:
//Dans le Menu "m", on active tous les items dans le groupe d'identifiant "R.id.group2"
//m.setGroupEnabled(R.id.group2, true);
//return true;
Intent intent = new Intent(context, Form.class);
startActivity(intent);
//break;
//case R.id.item2:
//db.clearDataBase(db);
//break;
}
return super.onOptionsItemSelected(item);
}
}
In the MainActivity, when I call the menu, there are two options. The second one is supposed to delete all conctacts from the list. My friends, I don't how to implement it, please help
Thanks a lot in advance, Karen.
