flutter select return null sqlite

Question

I'm new on SQLite and flutter. I'm trying to access an SQLite database (which is on my computer in the project folder at '~/Work/FlutterTest/ProjectTestFlutter/poa.db'.

But I have null when I try to cast my List to String.

There is my code :

class _DbPageState extends State<DbPage> {
  String data;
  var databasesPath;
  String path;
  Database database;

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        body: Container(
      child: Row(
        children: <Widget>[
          new IconButton(
              onPressed: () {
                data = getRecords().toString();
              },
              icon: Icon(Icons.more_vert)),
          new Text(
            data,
          )
        ],
      ),
    ));
  }

  Future<void> openDb() async {
    var databasesPath = await getDatabasesPath();
    String path = join(databasesPath, '~/Work/FlutterTest/ProjectTestFlutter/poa.db');

    database = await openDatabase(path, version: 1);
  }

  Future<List<Map>> getRecords() async {
    List<Map> list = await database.rawQuery('SELECT * FROM tbl1');
    return list;
  }

  Future<void> closeDb() async {
    await database.close();
  }
}

Is the database being opened correctly? Because in order to open a preinitialized db in Flutter, you need to copy it to the device from the assets folder in the first place. You are getting the path as a computer path, which should not work. — Martyns
– Martyns, Commented Apr 30, 2019 at 10:50
so you are trying to access a db file that is on your computer from an app running from your device? — Ryosuke
– Ryosuke, Commented Apr 30, 2019 at 10:50
getDatabasesPath will give you a path in your device. You should make your db file path something like databasesPath + '/poa.db'. But again, you should copy it first from the flutter assets bundle to that path. — Martyns
– Martyns, Commented Apr 30, 2019 at 11:05
@Martyns oh so no it not opened correctly though. Could you provide an answer, please? — Itoun
– Itoun, Commented Apr 30, 2019 at 11:06

Martyns · Accepted Answer · 2019-04-30 11:19:08Z

1

When app starts for example, copy the db to your device.

ByteData data = await rootBundle.load("assets/poa.db");
List<int> bytes = data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);

var databasesPath = await getDatabasesPath();
String dbPath = join(databasesPath, "poa.db");
await File(dbPath).writeAsBytes(bytes);

Remember to add the db file to the pubspec.yml, just as you would do with image resources. After that you could open it from the widget with:

var databasesPath = await getDatabasesPath();
String dbPath = join(databasesPath, "poa.db");
var database = await openDatabase(dbPath, version: 1);

edited Apr 30, 2019 at 11:19

answered Apr 30, 2019 at 11:11

Martyns

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1 Comment

Martyns Over a year ago

@Itoun That is great!

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