android studio SQL数据存储

Android Studio中可以使用SQLiteOpenHelper类来实现SQLite数据存储。下面是一个简单的示例：

1. 创建一个继承自SQLiteOpenHelper的类，重写onCreate()和onUpgrade()方法：

public class MyDatabaseHelper extends SQLiteOpenHelper {
    private static final String DB_NAME = "mydatabase.db";
    private static final int DB_VERSION = 1;

    public MyDatabaseHelper(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE mytable (_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS mytable");
        onCreate(db);
    }
}

2. 在需要使用数据库的Activity中，创建MyDatabaseHelper对象，并调用getWritableDatabase()方法获取可写的数据库对象：

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

3. 使用SQLiteDatabase对象进行数据库操作，例如插入数据：

ContentValues values = new ContentValues();
values.put("name", "张三");
values.put("age", 20);
db.insert("mytable", null, values);

4. 查询数据：

Cursor cursor = db.query("mytable", null, null, null, null, null, null);
if (cursor.moveToFirst()) {
    do {
        String name = cursor.getString(cursor.getColumnIndex("name"));
        int age = cursor.getInt(cursor.getColumnIndex("age"));
        Log.d("MainActivity", "name: " + name + ", age: " + age);
    } while (cursor.moveToNext());
}
cursor.close();