安卓实现一个记账本（SQLite存储数据）

以下是一个简单的记账本应用程序的示例代码，使用了SQLite数据库来存储记录。

首先，创建一个Account类，用于表示账目信息：

public class Account {
    public int id;
    public String description;
    public float amount;
 
    public Account(String description, float amount) {
        this.description = description;
        this.amount = amount;
    }
 
    // 空构造器，用于ORM
    public Account() {}
 
    // Getter和Setter略...
}

然后，创建一个DatabaseHelper类，用于管理数据库的创建和维护：

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
 
public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "account_db";
    private static final int DATABASE_VERSION = 1;
    private static final String TABLE_NAME = "accounts";
 
    public DatabaseHelper(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,"
                + "DESC TEXT,"
                + "AMOUNT REAL" + ")";
        db.execSQL(CREATE_TABLE);
    }
 
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }
}

最后，创建一个AccountManager类，用于账目的增删改查操作：

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
 
import java.util.ArrayList;
import java.util.List;
 
public class AccountManager {
    private DatabaseHelper dbHelper;
    private SQLiteDatabase db;
 
    public AccountManager(Context context) {
        dbHelper = new DatabaseHelper(context);
    }
 
    public void addAccount(Account account) {
        db = dbHelper.getWritableDatabase();
 
        ContentValues values = new ContentValues();
        values.put("DESC", account.description);
        values.put("AMOUNT", account.amount);
 
        db.insert(DatabaseHelper.TABLE_NAME, null, values);
        db.close();
    }
 
    public List<Account> getAllAccounts() {
        List<Account> accounts = new ArrayList