Я использую следующий код для отображения значений, хранящихся в базе данных Android sqlite.
AndroidSQLiteTutorialActivity.java
public class AndroidSQLiteTutorialActivity extends Activity {
/** Called when the activity is first created. */
ArrayList alarmList = new ArrayList();
List<Contact> contacts;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ListView mListView = (ListView) findViewById(R.id.listView1);
ArrayAdapter mAdapter = new ArrayAdapter<String>(
AndroidSQLiteTutorialActivity.this,
android.R.layout.simple_list_item_1, alarmList);
mListView.setAdapter(mAdapter);
DatabaseHandler db = new DatabaseHandler(this);
/**
* CRUD Operations
* */
// Inserting Contacts
Log.d("Insert: ", "Inserting ..");
db.addContact(new Contact("10", "00", "0", "0", "0", "0", "0", "0"));
db.addContact(new Contact("04, "00", "0", "0", "0", "0", "0", "0"));
db.addContact(new Contact("05", "00", "0", "0", "0", "0", "0", "0"));
db.addContact(new Contact("07", "00", "0", "0", "0", "0", "0", "0"));
// Reading all contacts
Log.d("Reading: ", "Reading all contacts..");
contacts = db.getAllContacts();
for (Contact cn : contacts) {
String log = "Id: " + cn.getID() + " ,Hours: " + cn.get_hours()
+ " ,Minutes: " + cn.get_minutes() + " ,DaysOfWeeks: "
+ cn.get_daysofweek() + " ,AlarmTime: "
+ cn.get_alramTime() + " ,Enabled: " + cn.get_enabled()
+ " ,Vibrate: " + cn.get_vibrate() + " ,Message: "
+ cn.get_message() + " ,Alert: " + cn.get_alert();
// Writing Contacts to log
String timeDisplay = cn.get_hours() + ":" + cn.get_minutes();
alarmList.add(timeDisplay);
Log.d("Name: ", log);
}
}
}
DatabaseHandler.java
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 3;
// 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";
public static final String KEY_HOUR = "hours";
public static final String KEY_MINUTES = "minutes";
public static final String KEY_DAYSOFWEEK = "daysofweek";
public static final String KEY_ALARMTIME = "alramtime";
public static final String KEY_ENABLED = "enabled";
public static final String KEY_VIBRATE = "vibrate";
public static final String KEY_MESSAGE = "message";
public static final String KEY_ALERT = "alert";
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 IF NOT EXISTS "
+ TABLE_CONTACTS + "(" + KEY_ID + " INTEGER PRIMARY KEY,"
+ KEY_HOUR + " TEXT," + KEY_MINUTES + " TEXT," + KEY_DAYSOFWEEK
+ " TEXT," + KEY_ALARMTIME + " TEXT," + KEY_ENABLED + " TEXT,"
+ KEY_VIBRATE + " TEXT," + KEY_MESSAGE + " TEXT," + KEY_ALERT
+ " 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
void addContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_HOUR, contact.get_hours());
values.put(KEY_MINUTES, contact.get_minutes());
values.put(KEY_DAYSOFWEEK, contact.get_daysofweek());
values.put(KEY_ALARMTIME, contact.get_alramTime());
values.put(KEY_ENABLED, contact.get_enabled());
values.put(KEY_VIBRATE, contact.get_vibrate());
values.put(KEY_MESSAGE, contact.get_message());
values.put(KEY_ALERT, contact.get_alert());
// 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_HOUR, KEY_MINUTES, KEY_DAYSOFWEEK, KEY_ALARMTIME,
KEY_ENABLED, KEY_VIBRATE, KEY_MESSAGE, KEY_ALERT }, 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), cursor.getString(5), cursor.getString(6),
cursor.getString(7), cursor.getString(8));
// 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.set_hours(cursor.getString(1));
contact.set_minutes(cursor.getString(2));
contact.set_daysofweek(cursor.getString(3));
contact.set_alramTime(cursor.getString(4));
contact.set_enabled(cursor.getString(5));
contact.set_vibrate(cursor.getString(6));
contact.set_message(cursor.getString(7));
contact.set_alert(cursor.getString(8));
// 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_HOUR, contact.get_hours());
values.put(KEY_MINUTES, contact.get_minutes());
values.put(KEY_DAYSOFWEEK, contact.get_daysofweek());
values.put(KEY_ALARMTIME, contact.get_alramTime());
values.put(KEY_ENABLED, contact.get_enabled());
values.put(KEY_VIBRATE, contact.get_vibrate());
values.put(KEY_MESSAGE, contact.get_message());
values.put(KEY_ALERT, contact.get_alert());
// updating row
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
}
// 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();
}
}
Contact.java
public class Contact {
public String get_alramTime() {
return this._alramTime;
}
public void set_alramTime(String _alramTime) {
this._alramTime = _alramTime;
}
public String get_enabled() {
return this._enabled;
}
public void set_enabled(String _enabled) {
this._enabled = _enabled;
}
public String get_vibrate() {
return this._vibrate;
}
public void set_vibrate(String _vibrate) {
this._vibrate = _vibrate;
}
public String get_message() {
return this._message;
}
public void set_message(String _message) {
this._message = _message;
}
public String get_alert() {
return this._alert;
}
public void set_alert(String _alert) {
this._alert = _alert;
}
public String get_hours() {
return this._hours;
}
public void set_hours(String _hours) {
this._hours = _hours;
}
public String get_minutes() {
return this._minutes;
}
public void set_minutes(String _minutes) {
this._minutes = _minutes;
}
public String get_daysofweek() {
return this._daysofweek;
}
public void set_daysofweek(String _daysofweek) {
this._daysofweek = _daysofweek;
}
// private variables
int _id;
String _hours;
String _minutes;
String _daysofweek;
String _alramTime;
String _enabled;
String _vibrate;
String _message;
String _alert;
// Empty constructor
public Contact() {
}
// constructor
public Contact(int id, String hours, String minutes, String daysofweek,
String alarmtime, String enabled, String vibrate, String message,
String alert) {
this._id = id;
this._hours = hours;
this._minutes = minutes;
this._daysofweek = daysofweek;
this._alramTime = alarmtime;
this._enabled = enabled;
this._vibrate = vibrate;
this._message = message;
this._alert = alert;
}
// constructor
public Contact(String hours, String minutes, String daysofweek,
String alarmtime, String enabled, String vibrate, String message,
String alert) {
this._hours = hours;
this._minutes = minutes;
this._daysofweek = daysofweek;
this._alramTime = alarmtime;
this._enabled = enabled;
this._vibrate = vibrate;
this._message = message;
this._alert = alert;
}
// getting ID
public int getID() {
return this._id;
}
// setting id
public void setID(int id) {
this._id = id;
}
}
Здесь моя проблема заключается в том, что при отображении значений базы данных в режиме просмотра списка она умножалась при каждом выполнении.При создании таблицы я использовал «Создать таблицу, если она не существует», но таблица создавалась при каждом выполнении.Как я могу решить это?