Flutter FutureBuilder not building with data from sqlite - sqlite

Question

I'm very new in flutter, and are trying to write the app that will take value from sqlite. From what I tried, it needs to use FutureBuilder widget.
But the following code I wrote, the FutureBuilder widget seems to get data from sqlite, but the "builder" property was never called:
import 'package:flutter/material.dart';
import 'package:flutter_spinkit/flutter_spinkit.dart';
import 'package:flutterapp/dbHelper.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
routes:{
"/": (context) =>Test()
}
);
}
}
class Test extends StatefulWidget {
#override
_TestState createState() => _TestState();
}
class _TestState extends State<Test> {
bool nameCheck = false; // Use to check name textfield has correctly be inputed
TextEditingController nameController = TextEditingController();
#override
Widget build(BuildContext context) {
return Scaffold(
body:Column(
children: <Widget>[
SizedBox(height:300),
Row(
children: <Widget>[
Expanded(
child: TextField(
controller: nameController,
)
),
IconButton(
icon: Icon(Icons.check_circle),
onPressed:(){
return FutureBuilder(
future: getData(nameController.text),
builder: (BuildContext context, AsyncSnapshot<List<Map>>snapshot) {
print("Start future"); // never get printed
List<Widget> children;
if (snapshot.hasData) {
children = <Widget>[
Builder(
builder: (BuildContext context) {
print("got data");
final result = snapshot.data;
print(result) ; // never get printed
setState(() {
nameCheck = true;
});
return Container();
})
];
} else {
children = <Widget>[
AlertDialog(
content: SpinKitCircle(
color: Colors.white,
size: 80.0,
))
];
}
return Center(
child: Container(
color: Colors.blue,
child: Column(
mainAxisAlignment:
MainAxisAlignment
.center,
crossAxisAlignment:
CrossAxisAlignment
.center,
children: children,
)));
});}
)
],
),
Builder(
builder: (BuildContext context){
if (nameCheck == true){
return Text("test");
}
return Container();
}
)
],
)
);
}
}
Future<List<Map>> getData(String input_name) async{
final dbHelper = DBHelper.instance;
await dbHelper.database;
final result = await dbHelper.query("SELECT * FROM Guest WHERE Name = \"$input_name\"");
print(result); // This get printed
return result;
}
The DBHelper code is as follow, basically it just set up a sqlite database and some database operation:
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';
import 'dart:io';
import 'package:path_provider/path_provider.dart';
class DBHelper {
static final _databaseName = "MonetaryDB.db";
static final _databaseVersion = 1;
static final create_table_Test = "CREATE TABLE \"Guest\" (\"Name\" TEXT NOT NULL PRIMARY KEY, \"Money\" INTEGER, \"Person\" INTEGER)";
static final String insert_guest = "INSERT INTO Guest (Name, Money, Person) VALUES (\"testname\", 1000, 1)";
DBHelper._privateConstructor();
static final DBHelper instance = DBHelper._privateConstructor();
static Database _database;
Future<Database> get database async {
if (_database != null) {
return _database;}
else{
_database = await _initDatabase();
return _database;}
}
_initDatabase() async {
Directory documentsDirectory = await getApplicationDocumentsDirectory();
String path = join(documentsDirectory.path, _databaseName);
return await openDatabase(path,
version: _databaseVersion,
onCreate: _onCreate,
);
}
Future _onCreate(Database db, int version) async {
await db.execute(create_table_Test);
await db.rawInsert(insert_guest);
}
Future<int> insert(String statement) async {
Database db = await instance.database;
return await db.rawInsert(statement);
}
Future<List<Map>> query(String statement) async {
Database db = await instance.database;
return await db.rawQuery(statement);
}
Future<int> update(String statement) async{
Database db = await instance.database;
return await db.rawUpdate(statement);
}
Future<int> delete(String statement) async{
Database db = await instance.database;
return db.rawDelete(statement);
}
}
If I simply change the IconButton onPressed function into setState((){nameCheck = true}), The Text("test") widget will show, so the problem must be the FutureBuilder. Also, the getData() function can get the correct result from the sqlite database
I have no idea why the FutureBuilder doesn't get build, did someone have any idea of it?
Thanks!

Answer 1

So with the help in the comment section, I change the code and it worked:
...
Widget build(BuildContext context) {
return Scaffold(
body:Column(
children: <Widget>[
SizedBox(height:300),
Row(
children: <Widget>[
Expanded(
child: TextField(
controller: nameController,
)
),
IconButton(
icon: Icon(Icons.check_circle),
onPressed:(){
return showDialog(
context: context,
builder: (BuildContext context){
return AlertDialog(
actions: <Widget>[
SizedBox(
width: 300,
height: 300,
child: FutureBuilder(
future: getData(nameController.text),
builder: (BuildContext context, AsyncSnapshot<List<Map>>snapshot) {
if (snapshot.hasData) {
final result = snapshot.data;
SchedulerBinding.instance.addPostFrameCallback((_) => setState(() {
nameCheck = true;
}));
Navigator.pop(context, true);
}
else {
return Container(
child: SpinKitCircle(
color: Colors.white,
size: 80.0,
));
}
return Container(color: Colors.blue);
})
),
],
);
}
);
}
)
],
),
Builder(
builder: (BuildContext context){
if (nameCheck == true){
return Text("test");
}
return Container();
}
)
],
)
);
}
...
The other codes are still the same.
Like the comment section above had suggested, the main problem is that there will be no place to build for the widget the FutureBuilder that is going to built. To solve this problem, I place the FutureBuilder widget into the AlertDialog widget, since that I still want to keep the SpinKitCircle widget when loading.
I also gave up the Column widget at the end of the FutureBuilder widget, and deleted the Builder widget at the beginning of the FutureBuilder widget, which it was no longer needed when there was no Column.
The above codes still throw an acceptable exception:"setState() or markNeedsBuild() called during build." But the whole things still can run, so I will try to fix that the other day.
Thanks for the suggestion in the comment section.