android -创建存储文本的数据库

// 创建数据库帮助类
public class DBHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "mydatabase.db";
    private static final int DATABASE_VERSION = 1;

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

    @Override
    public void onCreate(SQLiteDatabase db) {
        // 创建表结构
        String createTableQuery = "CREATE TABLE IF NOT EXISTS text_data (id INTEGER PRIMARY KEY AUTOINCREMENT, content TEXT)";
        db.execSQL(createTableQuery);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // 数据库版本升级时的操作
        if (oldVersion < newVersion) {
            db.execSQL("DROP TABLE IF EXISTS text_data");
            onCreate(db);
        }
    }
}

// 定义数据模型类
public class TextData {
    private int id;
    private String content;

    public TextData(int id, String content) {
        this.id = id;
        this.content = content;
    }

    // 省略getter和setter方法
}

// 执行数据库操作
public class MainActivity extends AppCompatActivity {
    private DBHelper dbHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        dbHelper = new DBHelper(this);
        SQLiteDatabase db = dbHelper.getWritableDatabase();

        // 插入数据
        ContentValues values = new ContentValues();
        values.put("content", "Hello, World!");
        db.insert("text_data", null, values);

        // 查询数据
        Cursor cursor = db.query("text_data", null, null, null, null, null, null);
        if (cursor != null && cursor.moveToFirst()) {
            int id = cursor.getInt(cursor.getColumnIndex("id"));
            String content = cursor.getString(cursor.getColumnIndex("content"));
            TextData textData = new TextData(id, content);
            // 处理查询结果
        }

        // 关闭数据库连接
        db.close();
    }
}