Android——Sqlite数据库——实现联系人信息的添加、查询、修改以及删除功能

以下是一个简化的示例代码，展示了如何在Android中使用SQLite数据库来实现基本的联系人信息添加、查询、修改和删除功能。

public class ContactsDatabaseHelper extends SQLiteOpenHelper {
 
    private static final String DATABASE_NAME = "contacts.db";
    private static final int DATABASE_VERSION = 1;
    private static final String TABLE_NAME = "contacts_table";
 
    public ContactsDatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
 
    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME + "("
                + "ID INTEGER PRIMARY KEY AUTOINCREMENT,"
                + "NAME TEXT,"
                + "PHONE TEXT,"
                + "EMAIL TEXT" + ")";
        db.execSQL(CREATE_TABLE);
    }
 
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }
 
    // 添加联系人信息
    public boolean addContact(Contact contact) {
        SQLiteDatabase db = this.getWritableDatabase();
 
        ContentValues values = new ContentValues();
        values.put("NAME", contact.getName());
        values.put("PHONE", contact.getPhoneNumber());
        values.put("EMAIL", contact.getEmail());
 
        long result = db.insert(TABLE_NAME, null, values);
        return result != -1;
    }
 
    // 查询所有联系人信息
    public List<Contact> getAllContacts() {
        List<Contact> contactList = new ArrayList<>();
        SQLiteDatabase db = this.getReadableDatabase();
 
        Cursor cursor = db.query(TABLE_NAME, new String[]{"ID", "NAME", "PHONE", "EMAIL"}, null, null, null, null, null);
        if (cursor.moveToFirst()) {
            do {
                Contact contact = new Contact();
                contact.setID(Integer.parseInt(cursor.getString(0)));
                contact.setName(cursor.getString(1));
                contact.setPhoneNumber(cursor.getString(2));
                contact.setEmail(cursor.getString(3));
                contactList.add(contact);
            } while (cursor.moveToNext());
        }
        cursor.close();
        return contactList;
    }
 
    // 根据ID查询联系人信息
    public Contact getContact(int id) {
        SQLiteDatabase db = this.getReadableDatabase();
 
        Cursor cursor = db.query(TABLE_NAME, new String[]{"ID", "NAME", "PHONE", "EMAIL"}, "ID =