Flutter How to populate data from sqflite to dropdown list - flutter

Question

I have seen the questions in stackoverflow which are quite similar to my question, but those question and answer dint work for me. So here is my question how to populate data from sqflite to dropdown list. Below are the dart files which I have written.Please help me with the question
dbhelper.dart
import 'package:abc/model/manage_categories.dart';
import 'package:sqflite/sqflite.dart';
import 'dart:async';
import 'dart:io';
import 'package:path_provider/path_provider.dart';
class DatabaseHelper {
static DatabaseHelper _databaseHelper; // Singleton DatabaseHelper
static Database _database; // Singleton Database
String categoriesTable = 'categories_table';
String colId = 'id';
String colTitle = 'title';
String colDate = 'date';
DatabaseHelper._createInstance(); // Named constructor to create instance of DatabaseHelper
factory DatabaseHelper() {
if (_databaseHelper == null) {
_databaseHelper = DatabaseHelper._createInstance(); // This is executed only once, singleton object
}
return _databaseHelper;
}
Future<Database> get database async {
if (_database == null) {
_database = await initializeDatabase();
}
return _database;
}
Future<Database> initializeDatabase() async {
// Get the directory path for both Android and iOS to categories database.
Directory directory = await getApplicationDocumentsDirectory();
String path = directory.path + 'categoriess.db';
// Open/create the database at a given path
var categoriessDatabase = await openDatabase(path, version: 1, onCreate: _createDb);
return categoriessDatabase;
}
void _createDb(Database db, int newVersion) async {
await db.execute('CREATE TABLE $categoriesTable($colId INTEGER PRIMARY KEY AUTOINCREMENT, $colTitle TEXT, '
'$colDate TEXT)');
}
// Fetch Operation: Get all categories objects from database
Future<List<Map<String, dynamic>>> getCategoriesMapList() async {
Database db = await this.database;
// var result = await db.rawQuery('SELECT * FROM $categoriesTable order by $colTitle ASC');
var result = await db.query(categoriesTable, orderBy: '$colTitle ASC');
return result;
}
// Insert Operation: Insert a categories object to database
Future<int> insertCategories(Categories categories) async {
Database db = await this.database;
var result = await db.insert(categoriesTable, categories.toMap());
return result;
}
// Update Operation: Update a categories object and save it to database
Future<int> updateCategories(Categories categories) async {
var db = await this.database;
var result = await db.update(categoriesTable, categories.toMap(), where: '$colId = ?', whereArgs: [categories.id]);
return result;
}
Future<int> updateCategoriesCompleted(Categories categories) async {
var db = await this.database;
var result = await db.update(categoriesTable, categories.toMap(), where: '$colId = ?', whereArgs: [categories.id]);
return result;
}
// Delete Operation: Delete a categories object from database
Future<int> deleteCategories(int id) async {
var db = await this.database;
int result = await db.rawDelete('DELETE FROM $categoriesTable WHERE $colId = $id');
return result;
}
// Get number of categories objects in database
Future<int> getCount() async {
Database db = await this.database;
List<Map<String, dynamic>> x = await db.rawQuery('SELECT COUNT (*) from $categoriesTable');
int result = Sqflite.firstIntValue(x);
return result;
}
// Get the 'Map List' [ List<Map> ] and convert it to 'categories List' [ List<Categories> ]
Future<List<Categories>> getCategoriesList() async {
var categoriesMapList = await getCategoriesMapList(); // Get 'Map List' from database
int count = categoriesMapList.length; // Count the number of map entries in db table
List<Categories> categoriesList = List<Categories>();
// For loop to create a 'categories List' from a 'Map List'
for (int i = 0; i < count; i++) {
categoriesList.add(Categories.fromMapObject(categoriesMapList[i]));
}
return categoriesList;
}
}
Add_store_item.dart
import 'package:flutter/material.dart';
import 'package:abc/database/dbhelper_categories.dart';
import 'package:abc/database/dbhelper_manage_inventory.dart';
import 'package:abc/model/Manageinventory_class.dart';
import 'package:abc/model/manage_categories.dart';
class AddStoreItem extends StatefulWidget {
final Inventory inventory;
AddStoreItem(this.inventory);
#override
State<StatefulWidget> createState() => new AddStoreItemState();
}
class AddStoreItemState extends State<AddStoreItem> {
DatabaseHelper databaseHelper = DatabaseHelper();
List<Categories> categoriesList = <Categories>[];
int count = 0;
DBProvider _db = DBProvider();
TextEditingController _itemController;
TextEditingController _quantityController;
TextEditingController _categoryController;
TextEditingController _unitController;
TextEditingController _locationController;
#override
void initState() {
super.initState();
_loadCategorieslist();
_itemController = new TextEditingController(text: widget.inventory.item);
_quantityController = new TextEditingController(text: widget.inventory.quantity);
_categoryController = new TextEditingController(text: widget.inventory.category);
_unitController = new TextEditingController(text: widget.inventory.unit);
_locationController = new TextEditingController(text: widget.inventory.location);
}
_loadCategorieslist()async{
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Add Inventory')
),
body: SingleChildScrollView(
child: Container(
margin: EdgeInsets.all(15.0),
alignment: Alignment.center,
child: Column(
children: <Widget>[
SizedBox(height: 10),
TextField(
controller: _itemController,
decoration: InputDecoration(labelText: 'Item'),
),
SizedBox(height: 10),
TextField(
controller: _quantityController,
decoration: InputDecoration(labelText: 'Quantity'),
),
SizedBox(height: 10),
DropdownButton<String>(
value: categoriesList,
items: categoriesList.map((String){
return DropdownMenuItem<String>(
value: value,
child: Text(value),
);
}),
isExpanded: true,
onChanged: (value) {
print("value: $value");
},
hint: Text(
"Units",
style: TextStyle(
// color: Colors.black,
),
),
),
DropdownButton<String>(
items: [
DropdownMenuItem<String>(
value: "1",
child: Text(
"First",
),
),
DropdownMenuItem<String>(
value: "2",
child: Text(
"Second",
),
),
],
isExpanded: true,
onChanged: (value) {
print("value: $value");
},
hint: Text(
"Location",
style: TextStyle(
// color: Colors.black,
),
),
),
SizedBox(height: 10),
RaisedButton(
child: (widget.inventory.id != null) ? Text('Update') : Text('Add Inventory'),
onPressed: () {
_addInventory();
},
),
],
),
),
),
);
}
void _addInventory() {
if (widget.inventory.id != null) {
_db
.updateNote(Inventory.withId(
widget.inventory.id,
_itemController.text,
_quantityController.text,
_categoryController.text,
_unitController.text,
_locationController.text,
))
.then((_) => Navigator.pop(context, 'update'));
} else {
_db
.saveNote(Inventory(
_itemController.text,
_quantityController.text,
_categoryController.text,
_unitController.text,
_locationController.text,
))
.then((_) => Navigator.pop(context, 'save'));
}
}
}

Answer 1

This how I managed to populate the list of data from sqflite to drop down
Declared list from sqflite to AddStoreItemState as below
DatabaseHelper databaseHelper = DatabaseHelper();
List<Categories> categoriesList ;
Categories _category;
Now wrap the drop down button as below
Center(
child: DropdownButtonFormField<Categories>(
hint: Text('Categories'),
value: _category,
onChanged: (Categories value){
setState(() {
_category = value;
});
},
items: categoriesList.map((user) => DropdownMenuItem<Categories>(
child: Text(user.cname),
value: user,
)
).toList(),
),
),

Answer 2

In AddStoreItemState change your _loadCategorieslist()async method to:
Future<List<Categories>> _loadCategorieslist() async => databaseHelper.getCategoriesMapList();
And wrap your DropdownButton with a FutureBuilder

Answer 3

This is how I read data from SqfLite to use it in a drop-down or data table, in this case barcode records.
Here is the model, which includes a fromJson() function like below:
class Barcode {
String code;
String itemNo;
Barcode({
this.code,
this.itemNo,
});
Map<String, dynamic> toMap() => {
'code': code,
'itemNo': itemNo,
};
factory Barcode.fromJson(Map<String, dynamic> parsedJson) {
return Barcode(
code: parsedJson['code'],
itemNo: parsedJson['itemNo'],
);
}
}
Here is how I read barcodes (all) from SqfLite:
static Future<List<Barcode>> getAll() async {
final db = await DbUtil.database;
var response = await db.query(tableName);
List<Barcode> list = response.map((c) => Barcode.fromJson(c)).toList();
return list;
}
Here is for reading just one barcode:
static Future<Barcode> get(String barcode) async {
final db = await DbUtil.database;
var response = await db.query(tableName, where: "$pkName = ?", whereArgs: ['$barcode']);
return response.isNotEmpty ? Barcode.fromJson(response.first) : null;
}
Then to call it:
var barcode = await BarcodeDb.get(scanText);
Try this out, it should work for you.