新建一個class extends SQLiteOpener

getWritableDatabase function 可以打開資料庫

public class MySQLiteHelper extends SQLiteOpenHelper {

//    public static final String TABLE_COMMENTS = "comments";
//    public static final String COLUMN_ID = "_id";
//    public static final String COLUMN_COMMENT = "comment";
//
//    private static final String DATABASE_NAME = "commments.db";
//    
private static final int DATABASE_VERSION = 1;
    public MySQLiteHelper(Context context,String name,SQLiteDatabase.CursorFactory factory,int version) {
        super(context, name,factory,version);
              //上下文 資料庫名 cursor 版本號
        mContext=context;
    }
    // Database creation sql statement
    private static final String CREATE_BOOK = "create table BOOK"
            + "("
            + " id integer primary key autoincrement, " + "author text,"
            +"price real,"
            +"pages integer,"
            +"name text);";
    private static final String CREATE_CATEGORY = "create table Category"
            + "("
            + " id integer primary key autoincrement, " + "category text,"
            +"category_code integer);";
    private Context mContext;


    @Override
    public void onCreate(SQLiteDatabase database) {
        database.execSQL(CREATE_BOOK);
        database.execSQL(CREATE_CATEGORY);
        Toast.makeText(mContext,"sussed",Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(MySQLiteHelper.class.getName(),
                "Upgrading database from version " + oldVersion + " to "
                        + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS BOOK" );
        db.execSQL("DROP TABLE IF EXISTS Category" );
        onCreate(db);
    }

}

public class MainActivity extends AppCompatActivity {
    private MySQLiteHelper dbHelper;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        dbHelper = new MySQLiteHelper(this, "BookStore.db", null, 3);
        Button create=(Button) findViewById(R.id.create);
        
        create.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dbHelper.getWritableDatabase();
            }
        });
        
        Button add=(Button) findViewById(R.id.add);
        Button update=(Button) findViewById(R.id.up);
        
        update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SQLiteDatabase database=dbHelper.getWritableDatabase();
                 ContentValues values=new ContentValues();
                 values.put("price",11);
                 database.update(
                         "Book",values,"name=?",new String[]{
                                 "uuko"
                         });
            }
        });
        
        Button del =(Button)findViewById(R.id.del);
        Button query=(Button) findViewById(R.id.query);
        query.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SQLiteDatabase database=dbHelper.getWritableDatabase();
                Cursor cursor=database.query("Book",
                        null,null,null,
                        null,null,null);
                        //表 列 where條件 具體值 groupby having orderby
                if (cursor.moveToFirst()){
                    do {
                        String name=cursor.getString(cursor.getColumnIndex("name"));
                        Log.d("MainActivity", "onClick: "+name);
                    }while (cursor.moveToNext());
                }
                cursor.close();
            }
        });
        del.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SQLiteDatabase database=dbHelper.getWritableDatabase();
                ContentValues values=new ContentValues();
                database.delete("Book","pages>?",new String[] {"500"});
            }
        });
//
        add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SQLiteDatabase database=dbHelper.getWritableDatabase();
                ContentValues values=new ContentValues();
                //組裝數據
                values.put("name","uuko");
                values.put("author","yy");
                values.put("pages",444);
                values.put("price",10.55);
                database.insert("Book",null,values);
                values.put("name","ttt");
                values.put("author","tt");
                values.put("pages",41);
                values.put("price",3.55);
                database.insert("Book",null,values);
            }
        });

    }
}