在textView中仅显示SQLite数据库中的相关信息

// 创建SQLiteOpenHelper子类，用于创建和管理数据库
public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "mydatabase.db";
    private static final int DATABASE_VERSION = 1;

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

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

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // 升级数据库时的操作
    }

    // 查询数据库中的相关信息
    public String getDatabaseInfo() {
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery("SELECT * FROM mytable", null);

        StringBuilder stringBuilder = new StringBuilder();
        while (cursor.moveToNext()) {
            int id = cursor.getInt(cursor.getColumnIndex("id"));
            String name = cursor.getString(cursor.getColumnIndex("name"));
            stringBuilder.append("ID: ").append(id).append(", Name: ").append(name).append("\n");
        }

        cursor.close();
        db.close();

        return stringBuilder.toString();
    }
}

// 在Activity中使用DatabaseHelper类来获取数据库信息并显示在TextView中
public class MainActivity extends AppCompatActivity {
    private TextView textView;

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

        textView = findViewById(R.id.textView);

        // 创建DatabaseHelper实例
        DatabaseHelper databaseHelper = new DatabaseHelper(this);

        // 获取数据库信息并设置给TextView
        String databaseInfo = databaseHelper.getDatabaseInfo();
        textView.setText(databaseInfo);
    }
}