Develop Reference

Flutter permission to contact

My code is the file name is interface.dart. I'm calling the interface.dart from the main.dart
I'm getting a permission denied error when try to access the contacts in the emulator
I added the permission_handler dependency in the pubspec.yaml
Then added the permissions in the AndroidManifest.xml for both read and write
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:contacts_service/contacts_service.dart';
import 'package:permission_handler/permission_handler.dart';
import 'dart:io';
import 'dart:convert';
import 'package:url_launcher/url_launcher.dart';
import 'package:path_provider/path_provider.dart';
class Interface extends StatelessWidget {
const Interface({super.key});
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('pAM'),
),
body: const ContactSelector(),
);
}
}
class ContactSelector extends StatefulWidget {
const ContactSelector({super.key});
#override
_ContactSelectorState createState() => _ContactSelectorState();
}
class _ContactSelectorState extends State<ContactSelector> {
var status = Permission.contacts.status;
Contact _selectedContact = Contact();
late bool _isTrue;
#override
void initState() {
super.initState();
_readJson();
}
_selectContact() async {
List<Contact> contact =
await ContactsService.getContacts(withThumbnails: false);
setState(() {
_selectedContact = contact as Contact;
});
_saveContactToFile(_selectedContact);
}
_saveContactToFile(Contact contact) async {
final directory = await getApplicationDocumentsDirectory();
final file = File('${directory.path}/selected_contact.txt');
if (!(await file.exists())) {
file.create();
}
file.writeAsString(jsonEncode(contact.toMap()));
}
_readJson() async {
final directory = await getApplicationDocumentsDirectory();
final file = File('${directory.path}/true.json');
if (!(await file.exists())) {
file.createSync();
file.writeAsStringSync('{"isTrue":true}');
}
final content = jsonDecode(await file.readAsString());
setState(() {
_isTrue = content['isTrue'];
});
}
_promptMessage() {
if (_isTrue) {
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text('Select a message'),
content: SingleChildScrollView(
child: ListBody(
children: <Widget>[
InkWell(
child: const Text('How are you?'),
onTap: () {
_sendMessage('How are you?');
Navigator.of(context).pop();
}),
InkWell(
child: const Text('Did you have your lunch ?'),
onTap: () {
_sendMessage('Did you have your lunch ?');
Navigator.of(context).pop();
}),
InkWell(
child: const Text("What's for dinner?"),
onTap: () {
_sendMessage("What's for dinner?");
Navigator.of(context).pop();
}),
],
),
),
);
},
);
}
}
String? encodeQueryParameters(Map<String, String> params) {
return params.entries
.map((e) =>
'${Uri.encodeComponent(e.key)}=${Uri.encodeComponent(e.value)}')
.join('&');
}
_sendMessage(String message) async {
String phoneNumber = _selectedContact.phones.toString();
Uri uri = Uri(
scheme: 'sms',
path: phoneNumber,
query: encodeQueryParameters(<String, String>{
'body': 'Welcome to pAM',
}),
);
if (await canLaunchUrl(uri)) {
await canLaunchUrl(uri);
} else {
throw 'Could not send SMS';
}
}
#override
Widget build(BuildContext context) {
return MediaQuery(
data: MediaQueryData.fromWindow(WidgetsBinding.instance.window),
child: Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
if (_selectedContact != null)
Text(_selectedContact.displayName ?? 'No contact selected')
else
const Text('No contact selected'),
ElevatedButton(
onPressed: _selectContact,
child: const Text('Select Contact'),
),
ElevatedButton(
onPressed: _promptMessage,
child: const Text('Prompt Message'),
),
],
),
),
));
}
}

You are facing this issues because you haven't asked for the permission yet, refer the code below:
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:contacts_service/contacts_service.dart';
import 'package:permission_handler/permission_handler.dart';
import 'dart:io';
import 'dart:convert';
import 'package:url_launcher/url_launcher.dart';
import 'package:path_provider/path_provider.dart';
class Interface extends StatelessWidget {
const Interface({super.key});
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('pAM'),
),
body: const ContactSelector(),
);
}
}
class ContactSelector extends StatefulWidget {
const ContactSelector({super.key});
#override
_ContactSelectorState createState() => _ContactSelectorState();
}
class _ContactSelectorState extends State<ContactSelector> {
var status = Permission.contacts.status;
Contact _selectedContact = Contact();
late bool _isTrue;
#override
void initState() {
_readJson();
super.initState();
}
_selectContact() async {
if (await Permission.contacts.request().isGranted) {
List<Contact> contact =
await ContactsService.getContacts(withThumbnails: false);
setState(() {
_selectedContact = contact as Contact;
});
_saveContactToFile(_selectedContact);
}
}
_saveContactToFile(Contact contact) async {
final directory = await getApplicationDocumentsDirectory();
final file = File('${directory.path}/selected_contact.txt');
if (!(await file.exists())) {
file.create();
}
file.writeAsString(jsonEncode(contact.toMap()));
}
_readJson() async {
final directory = await getApplicationDocumentsDirectory();
final file = File('${directory.path}/true.json');
if (!(await file.exists())) {
file.createSync();
file.writeAsStringSync('{"isTrue":true}');
}
final content = jsonDecode(await file.readAsString());
setState(() {
_isTrue = content['isTrue'];
});
}
_promptMessage() {
if (_isTrue) {
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text('Select a message'),
content: SingleChildScrollView(
child: ListBody(
children: <Widget>[
InkWell(
child: const Text('How are you?'),
onTap: () {
_sendMessage('How are you?');
Navigator.of(context).pop();
}),
InkWell(
child: const Text('Did you have your lunch ?'),
onTap: () {
_sendMessage('Did you have your lunch ?');
Navigator.of(context).pop();
}),
InkWell(
child: const Text("What's for dinner?"),
onTap: () {
_sendMessage("What's for dinner?");
Navigator.of(context).pop();
}),
],
),
),
);
},
);
}
}
String? encodeQueryParameters(Map<String, String> params) {
return params.entries
.map((e) =>
'${Uri.encodeComponent(e.key)}=${Uri.encodeComponent(e.value)}')
.join('&');
}
_sendMessage(String message) async {
String phoneNumber = _selectedContact.phones.toString();
Uri uri = Uri(
scheme: 'sms',
path: phoneNumber,
query: encodeQueryParameters(<String, String>{
'body': 'Welcome to pAM',
}),
);
if (await canLaunchUrl(uri)) {
await canLaunchUrl(uri);
} else {
throw 'Could not send SMS';
}
}
#override
Widget build(BuildContext context) {
return MediaQuery(
data: MediaQueryData.fromWindow(WidgetsBinding.instance.window),
child: Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
if (_selectedContact != null)
Text(_selectedContact.displayName ?? 'No contact selected')
else
const Text('No contact selected'),
ElevatedButton(
onPressed: _selectContact,
child: const Text('Select Contact'),
),
ElevatedButton(
onPressed: _promptMessage,
child: const Text('Prompt Message'),
),
],
),
),
));
}
}

Check the permission status first as this:-
final status = Permission.contacts.request()
if(status.isGrantet){
// permission has granted now save the contact here
}
Refer this link for more details.

How can I change a background screen with a photo fetched from api in flutter?

I'm fetching images from https://pixabay.com/api/docs/ this web-page.
I'm trying to save that image with onTap() {} with Shared Preferences package and set as background on previous page. I tried to make Shared preferences class seperate but it was showing errors. So pref.setString() method I did in ontap() {} and pref.getString() in my Center() widget with ternary operator to show that if image url is empty, write text, if it contains image url, show image. I tried to put it into setState() {} method but there are all red squiggles. How can I achieve this?
Thank you very much in advance.
Here is my code:
this is the page I'm trying to set background image:
import 'package:abcde/authentication_screen/pages/photos_page.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
class AfterAuth extends StatefulWidget {
AfterAuth({Key? key}) : super(key: key);
static const String pathId = 'Welcome Page';
#override
State<AfterAuth> createState() => _AfterAuthState();
}
class _AfterAuthState extends State<AfterAuth> {
String welcomeScreen = 'Welcome to the club';
#override
void initState() {
// TODO: implement initState
super.initState();
//final prefs = await SharedPreferences.getInstance();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Welcome'),
),
drawer: Drawer(
backgroundColor: Colors.white,
child: ListView(
padding: EdgeInsets.zero,
children: [
const DrawerHeader(
decoration: BoxDecoration(
color: Colors.lightBlueAccent,
),
child: Text('Welcome'),
),
ListTile(
title: const Text(
'Bonjour',
),
onTap: () {
setState(() {
welcomeScreen = 'Bonjour';
});
Navigator.pop(context);
},
),
ListTile(
title: const Text('Hello'),
onTap: () {
setState(() {
welcomeScreen = 'Hello';
});
Navigator.pop(context);
},
),
ListTile(
title: const Text('Guten Tag'),
onTap: () {
setState(() {
welcomeScreen = 'Guten Tag';
});
Navigator.pop(context);
},
),
ListTile(
title: const Text('Au Revoir'),
onTap: () {
setState(() {
welcomeScreen = 'Au Revoir';
});
Navigator.pop(context);
},
),
ListTile(
title: const Text('Chao Bambino'),
onTap: () {
setState(() {
welcomeScreen = 'Chao Bambino';
});
Navigator.pop(context);
},
),
],
),
),
body: Center(
child: address == ''
? Text(welcomeScreen)
: Image(
image: NetworkImage(address),
),
),
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.lightBlue,
onPressed: () {
Navigator.pushNamed(context, PhotosPage.pathId);
},
child: const Icon(
Icons.add,
color: Colors.white,
),
),
);
}
String address = '';
internalMemory() async {
final prefs = await SharedPreferences.getInstance();
address = prefs.getString('urlAddress')!;
/* if(address!.isNotEmpty) {
isAddressEmpty = false;
}*/
return address;
}
}
this is the page where I fetch images from api and trying to save with Shared Preferences. actually not sure if it saves and not sure how to check it:
import 'package:flutter/material.dart';
import '../../services/photos_service.dart';
import 'package:shared_preferences/shared_preferences.dart';
class PhotosPage extends StatefulWidget {
const PhotosPage({Key? key}) : super(key: key);
static const String pathId = 'Photos page';
#override
State<PhotosPage> createState() => _PhotosPageState();
}
class _PhotosPageState extends State<PhotosPage> {
PhotosService photosService = PhotosService();
#override
void initState() {
super.initState();
photosService.getPhotos();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Photos'),
),
body: Padding(
padding: const EdgeInsets.all(16),
child: Column(children: [
_getProductTypeList(),
]),
),
);
}
Widget _buildListItem(
BuildContext context, AsyncSnapshot<dynamic> snapshot, int index) {
final photoItem = snapshot.data[index].previewURL;
print('photoItem is $photoItem');
return photoCard(context, photoItem);
}
Widget _buildList(BuildContext context, AsyncSnapshot<dynamic> snapshot) {
var values = snapshot.data;
return ListView.builder(
itemCount: snapshot.hasData ? snapshot.data.length : 0,
itemBuilder: (context, index) {
return _buildListItem(context, snapshot, index);
},
);
}
Widget _getProductTypeList() {
return Expanded(
child: FutureBuilder(
future: photosService.getPhotos(),
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
if (snapshot.connectionState == ConnectionState.waiting) {
return const Center(
child: LinearProgressIndicator(),
);
}
return _buildList(context, snapshot);
},
),
);
}
}
Widget photoCard(BuildContext context, String url) {
return GestureDetector(
onTap: () async {
final prefs = await SharedPreferences.getInstance();
await prefs.setString('urlAddress', url);
const snackBar =
SnackBar(content: Text('You saved image'));
ScaffoldMessenger.of(context).showSnackBar(snackBar);
},
child: Card(
child: Image(
image: NetworkImage(url),
),
),
);
}
this is my service/model
import 'dart:convert';
import 'package:http/http.dart';
const apiKey = '26711456-bde74f403cb42e77029bc1678';
const appUrl = 'https://pixabay.com/api/';
class PhotosService {
Future getData(String url) async {
print('Calling url: $url');
final response = await get(Uri.parse(url));
if (response.statusCode == 200) {
return response.body;
} else {
print(response.statusCode);
}
}
String? query;
List<PhotosModel> dataList = [];
Future<List<PhotosModel>> getPhotos() async {
final photosData = await getData('$appUrl?key=$apiKey&q=$query');
var data = json.decode(photosData);
var items = data["hits"];
items.forEach((element) {
dataList.add(PhotosModel.fromJson(element));
});
print('this is photos data: $photosData');
return dataList;
}
}
class PhotosModel {
String previewURL;
PhotosModel({required this.previewURL});
factory PhotosModel.fromJson(Map<dynamic, dynamic> json) =>
_commentFromJson(json);
Map<dynamic, dynamic> toJson() => photosModelToJson(this);
}
PhotosModel _commentFromJson(Map<dynamic, dynamic> json) {
return PhotosModel(
previewURL: json['previewURL'],
);
}
Map<dynamic, dynamic> photosModelToJson(PhotosModel instance) =>
<dynamic, dynamic>{
'previewURL': instance.previewURL,
};

Call your function on initState to set the background on restart the app.
#override
void initState() {
// TODO: implement initState
super.initState();
internalMemory();
//final prefs = await SharedPreferences.getInstance();
}
add setstate to your internalMemory() function to set background
internalMemory() async {
final prefs = await SharedPreferences.getInstance();
address = await prefs.getString('urlAddress')!;
setState((){});
}
also, add the function below to set the background when you navigate back.
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.lightBlue,
onPressed: () async {
await Navigator.pushNamed(context, PhotosPage.pathId);
internalMemory();
},
child: const Icon(
Icons.add,
color: Colors.white,
),
),

Flutter Multiselect Chips From API Contents

I am using this multi-select flutter package. It already has contents to view chips, but I want to load contents from API to do that instead.
I already added a fetchData() function to download the data from the API. Now, how do I get the JSON data into the chips multi-select?
Here is my code:
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:multiselect_formfield/multiselect_formfield.dart';
import 'package:multi_select_flutter/multi_select_flutter.dart';
import 'package:http/http.dart' as http;
import 'Includes/APILinks.dart';
void main() => runApp(Sample());
class Sample extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List _myActivities;
String _myActivitiesResult;
final formKey = new GlobalKey<FormState>();
#override
void initState() {
super.initState();
_myActivities = [];
this.fetchData();
}
_saveForm() {
var form = formKey.currentState;
if (form.validate()) {
form.save();
setState(() {
_myActivitiesResult = _myActivities.toString();
});
}
}
fetchData() async{
var url = CategorySection;
var response = await http.get(url);
if(response.statusCode == 200){
var items = json.decode(response.body);
print(items);
setState(() {
_myActivities = items;
});
} else {
setState(() {
_myActivities = [];
});
}
}
#override
Widget build(BuildContext context) {
final double maxWidth = MediaQuery.of(context).size.width;
final double maxHeight = MediaQuery.of(context).size.height;
return Scaffold(
appBar: AppBar(
title: Text('MultiSelect Formfield Example'),
),
body: Center(
child: Form(
key: formKey,
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
Container(
height: maxHeight/2,
width: maxWidth,
padding: EdgeInsets.all(16),
child: getListView(),
),
Container(
padding: EdgeInsets.all(8),
child: RaisedButton(
child: Text('Save'),
onPressed: _saveForm,
),
),
Container(
padding: EdgeInsets.all(16),
child: Text(_myActivitiesResult),
)
],
),
),
),
);
}
Widget getListView() {
return ListView.builder(
itemCount: _myActivities.length,
itemBuilder: (context, index){
return cardView(_myActivities[index]);
},
);
}
Widget cardView(item) {
var fullName = item;
return MultiSelectDialogField(
items: _myActivities,
title: Text("Animals"),
selectedColor: Colors.blue,
decoration: BoxDecoration(
color: Colors.blue.withOpacity(0.1),
borderRadius: BorderRadius.all(Radius.circular(40)),
border: Border.all(
color: Colors.blue,
width: 2,
),
),
buttonIcon: Icon(
Icons.pets,
color: Colors.blue,
),
buttonText: Text(
"Favorite Animals",
style: TextStyle(
color: Colors.blue[800],
fontSize: 16,
),
),
onConfirm: (results) {
_myActivities = results;
},
);
}
}

You can use a Future function with the return type that you want, in that case it will be Future<List<MultiSelectItem>>, then you would use async and await, it will be something like that:
Future<List<Item>> fetchItems(BuildContext context) async {
http.Response response = await http.get(
Uri.parse('your link for ur api'),
//you can ignore that part
headers: <String, String>{
'Authorization':
'Token ${Provider.of<Token>(context, listen: false).token}'
});
//here you turn the json to a <String, dynamic> map
var data = jsonDecode(response.body);
List<Item> result = [];
for (var item in data) {
//use your factory if you wanna to parse the data the way you want it
result.add(Item.fromJson(item));
}
//that should be your disered list
return result;
}

The FilterChip class provides a multiple select chip. Using FutureBuilder we can fetch future data and build the chips list. We can also call the API first, and then map the results with the filter chips.
Here is an example of a FilterChip, where chips are populated from an API using FutureBuilder:
import 'dart:convert';
import 'package:filterchip_sample/album.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'FilterChip Sample',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'FilterChip Sample'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final String title;
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
bool favorite = false;
final List<int> _filters = <int>[];
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: SingleChildScrollView(
padding: const EdgeInsets.all(20),
child: Column(
children: <Widget>[
FutureBuilder<List<Album>>(
future: _fetchAlbums(),
builder:
(BuildContext context, AsyncSnapshot<List<Album>> snapshot) {
Widget result;
if (snapshot.hasData) {
result = Wrap(
spacing: 5.0,
children: snapshot.data!.map((Album album) {
return FilterChip(
label: Text(album.title),
selected: _filters.contains(album.id),
onSelected: (bool value) {
setState(() {
if (value) {
if (!_filters.contains(album.id)) {
_filters.add(album.id);
}
} else {
_filters.removeWhere((int id) {
return id == album.id;
});
}
});
},
);
}).toList(),
);
} else if (snapshot.hasError) {
result = Text('Error: ${snapshot.error}');
} else {
result = const Text('Awaiting result...');
}
return result;
},
),
],
),
),
);
}
Future<List<Album>>? _fetchAlbums() async {
final response = await http
.get(Uri.parse('https://jsonplaceholder.typicode.com/albums/'));
if (response.statusCode == 200) {
var json = jsonDecode(response.body);
var albums = List<Album>.from(json.map((i) => Album.fromJson(i)));
return albums;
} else {
throw Exception('Failed to get albums');
}
}
}

Flutter: 'Future<dynamic>' is not a subtype of type 'String'

I'm trying to build a URL shortner using the following api: https://shrtco.de/docs/. I parsed the JSON file and tried to rebuild the listview. But after adding the url I'm getting the above error. The api seems to be working fine when I print it though. I don't know whats wrong. I'm a beginner in Flutter and Dart. Please help me.
class _homePageState extends State<homePage> {
getdata(String userUrl) async {
//JSON Parser
var url = 'https://api.shrtco.de/v2/shorten?url=$userUrl';
var respons = await http.get(url);
var result = jsonDecode(respons.body);
var shortlink = result['result']['short_link']; //dictionary parse
print(shortlink);
return shortlink;
}
Future<String> createAlertDialog(BuildContext context) {
//method for alertdialog
//promise to return string
TextEditingController customController =
TextEditingController(); //new texteditingc object
return showDialog(
context: context,
builder: (context) {
return AlertDialog(
title: Text("Enter URL: "),
content: TextField(
controller: customController,
),
actions: [
MaterialButton(
elevation: 5.0,
child: Text("OK"),
onPressed: () {
if (customController.text != null &&
customController.text != "") {
var getShortlink = getdata(customController.text);
item.add(getShortlink);
}
setState(() {});
Navigator.of(context).pop();
},
)
],
);
});
}
#override
Widget build(BuildContext context) {
String temp;
return Scaffold(
appBar: AppBar(
title: Text("Shortie"),
),
body: Padding(
padding: const EdgeInsets.all(8.0),
child: ListView.builder(
itemCount: item.length,
itemBuilder: (context, index) {
return ListTile(
leading: Icon(Icons.link),
title: Text(item[index]),
subtitle: Text("data"),
);
//return new Text();
},
),
),
floatingActionButton: FloatingActionButton(
onPressed: () {
createAlertDialog(context).then((onValue) {
temp = onValue;
print(temp);
});
},

You can copy paste run full code below
Step 1: getdata return Future<String>
Step 2: onPressed need async await
Step 3: put getShortlink in Navigator.of(context).pop(getShortlink);
code snippet
Future<String> getdata(String userUrl) async {
...
onPressed: () async {
String getShortlink;
if (customController.text != null &&
customController.text != "") {
getShortlink = await getdata(customController.text);
item.add(getShortlink);
}
setState(() {});
Navigator.of(context).pop(getShortlink);
},
working demo
full code
import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<String> item = [];
Future<String> getdata(String userUrl) async {
//JSON Parser
var url = 'https://api.shrtco.de/v2/shorten?url=$userUrl';
var respons = await http.get(url);
var result = jsonDecode(respons.body);
var shortlink = result['result']['short_link']; //dictionary parse
print(shortlink);
return shortlink;
}
Future<String> createAlertDialog(BuildContext context) {
//method for alertdialog
//promise to return string
TextEditingController customController =
TextEditingController(text: "example.org/very/long/link.html"); //new texteditingc object
return showDialog(
context: context,
builder: (context) {
return AlertDialog(
title: Text("Enter URL: "),
content: TextField(
controller: customController,
),
actions: [
MaterialButton(
elevation: 5.0,
child: Text("OK"),
onPressed: () async {
String getShortlink;
if (customController.text != null &&
customController.text != "") {
getShortlink = await getdata(customController.text);
item.add(getShortlink);
}
setState(() {});
Navigator.of(context).pop(getShortlink);
},
)
],
);
});
}
#override
Widget build(BuildContext context) {
String temp;
return Scaffold(
appBar: AppBar(
title: Text("Shortie"),
),
body: Padding(
padding: const EdgeInsets.all(8.0),
child: ListView.builder(
itemCount: item.length,
itemBuilder: (context, index) {
return ListTile(
leading: Icon(Icons.link),
title: Text(item[index]),
subtitle: Text("data"),
);
//return new Text();
},
),
),
floatingActionButton: FloatingActionButton(onPressed: () {
createAlertDialog(context).then((onValue) {
temp = onValue;
print(temp);
});
}));
}
}

createAlertDialog(BuildContext context) doesn't return a Future<String>, it's returns Future<T>, dynamic in your case.
https://api.flutter.dev/flutter/material/showDialog.html

flutter search bar with bloc with firestore

I do search app bar.I search data by title(substring) and return items.I have Ui,bloc,service classes.I dont know how to pass '$searchQuery' into bloc sink.I return stream list(in Ui),but firstly i need to filter my list by title(item) and put in sink.Could you give me some advise or examples?Should i fix my bloc class?
class Search extends StatefulWidget {
#override
_Search createState() => _Search();
}
class _Search extends State<Search> {
static final GlobalKey<ScaffoldState> scaffoldKey =
new GlobalKey<ScaffoldState>();
TextEditingController _searchQuery;
bool _isSearching = false;
String searchQuery = "Search query";
#override
void initState() {
super.initState();
_searchQuery = new TextEditingController();
}
void _startSearch() {
print("open search box");
ModalRoute.of(context)
.addLocalHistoryEntry(new LocalHistoryEntry(onRemove: _stopSearching));
setState(() {
_isSearching = true;
});
}
void _stopSearching() {
_clearSearchQuery();
setState(() {
_isSearching = false;
});
}
void _clearSearchQuery() {
print("close search box");
setState(() {
_searchQuery.clear();
updateSearchQuery("Search query");
});
}
Widget _buildTitle(BuildContext context) {
var horizontalTitleAlignment =
Platform.isIOS ? CrossAxisAlignment.center : CrossAxisAlignment.start;
return new InkWell(
onTap: () => scaffoldKey.currentState.openDrawer(),
child: new Padding(
padding: const EdgeInsets.symmetric(horizontal: 12.0),
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: horizontalTitleAlignment,
children: <Widget>[
const Text('Seach box'),
],
),
),
);
}
Widget _buildSearchField() {
return new TextField(
controller: _searchQuery,
autofocus: true,
decoration: const InputDecoration(
hintText: 'Search...',
border: InputBorder.none,
hintStyle: const TextStyle(color: Colors.white30),
),
style: const TextStyle(color: Colors.white, fontSize: 16.0),
onChanged: updateSearchQuery,
);
}
void updateSearchQuery(String newQuery) {
setState(() {
searchQuery = newQuery;
});
print("search query " + newQuery);
}
List<Widget> _buildActions() {
if (_isSearching) {
return <Widget>[
new IconButton(
icon: const Icon(Icons.clear),
onPressed: () {
if (_searchQuery == null || _searchQuery.text.isEmpty) {
Navigator.pop(context);
return;
}
_clearSearchQuery();
},
),
];
}
return <Widget>[
new IconButton(
icon: const Icon(Icons.search),
onPressed: _startSearch,
),
];
}
#override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
key: scaffoldKey,
appBar: new AppBar(
leading: _isSearching ? const BackButton() : null,
title: _isSearching ? _buildSearchField() : _buildTitle(context),
actions: _buildActions(),
),
body: new Center(
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Text(
'$searchQuery',
style: Theme.of(context).textTheme.display1,
)
],
),
),
));
}
}
class MovieService {
static final String _baseUrl = 'xxxx';
final CollectionReference _db;
MovieService() : _db = Firestore.instance.collection(_baseUrl);
Future<List<MovieEntity>> searchByString(String stringSearch) async {
final CollectionReference _dbs = Firestore.instance.collection(_baseUrl);
QuerySnapshot query =
await _dbs.where("Title", isEqualTo: stringSearch.substring(0, 1).toUpperCase()).getDocuments();
List<MovieEntity> products = query.documents
.map((doc) => MovieEntity.fromSnapshotJson(doc))
.toList();
return products;
}
}
class MovieBloc extends BlocBase {
String nameFilmSearchQuery;
final MovieService _productService;
MovieBloc(this._productService) {
_loadMovies();
}
final BehaviorSubject<List<MovieEntity>> _controllerSearch =
new BehaviorSubject<List<MovieEntity>>.seeded(List<MovieEntity>());
Observable<List<MovieEntity>> get listMoviesFluxSearch =>
_controllerSearch.stream;
Sink<List<MovieEntity>> get listMoviesEventSearch => _controllerSearch.sink;
_loadMovies() async {
listMoviesEventSearch.add(await _productService.searchByString(nameFilmSearchQuery));// i should pass '$searchQuery' here from Ui
}
#override
void dispose() {
_controllerSearch.close();
super.dispose();
}
}

A possible implementation of this Feature, includes a SearchDelegate used relatively to the main BLoC that changes states and events.
In this case the Resource needed is a City, so it is implemented a "SearchCity" class that extends SearchDelegate.
Overriding the method buildResults and BlocBuilder, it also adds a SearchCity event and some SearchCity states, in order to easily manage all possible operations related to the search operation itself.
class CitySearchEvent {
final String query;
const CitySearchEvent(this.query);
#override
String toString() => 'CitySearchEvent { query: $query }';
}
class CitySearchState {
final bool isLoading;
final List<City> cities;
final bool hasError;
const CitySearchState({this.isLoading, this.cities, this.hasError});
factory CitySearchState.initial() {
return CitySearchState(
cities: [],
isLoading: false,
hasError: false,
);
}
factory CitySearchState.loading() {
return CitySearchState(
cities: [],
isLoading: true,
hasError: false,
);
}
factory CitySearchState.success(List<City> cities) {
return CitySearchState(
cities: cities,
isLoading: false,
hasError: false,
);
}
factory CitySearchState.error() {
return CitySearchState(
cities: [],
isLoading: false,
hasError: true,
);
}
#override
String toString() =>
'CitySearchState {cities: ${cities.toString()}, isLoading: $isLoading, hasError: $hasError }';
}
Here is the edits added to the main BLoC implementation, that uses previously created States and Events in order to contruct a better business logic for the operation.
class CityBloc extends Bloc<CitySearchEvent, CitySearchState> {
#override
CitySearchState get initialState => CitySearchState.initial();
#override
void onTransition(Transition<CitySearchEvent, CitySearchState> transition)
{
print(transition.toString());
}
#override
Stream<CitySearchState> mapEventToState(CitySearchEvent event) async* {
yield CitySearchState.loading();
try {
List<City> cities = await _getSearchResults(event.query);
yield CitySearchState.success(cities);
} catch (_) {
yield CitySearchState.error();
}
}
Future<List<City>> _getSearchResults(String query) async {
// Simulating network latency
await Future.delayed(Duration(seconds: 1));
return [City('Chicago'), City('Los Angeles')];
}
}
Here is a full example of a single-file implementation that includes both UI and search methods.
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:bloc/bloc.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: BlocProvider(
create: (_) => CityBloc(),
child: MyHomePage(),
));
}
}
class MyHomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Search Delegate'),
),
body: Container(
child: Center(
child: RaisedButton(
child: Text('Show search'),
onPressed: () async {
City selected = await showSearch<City>(
context: context,
delegate: CitySearch(BlocProvider.of<CityBloc>(context)),
);
print(selected);
},
),
),
),
);
}
}
class City {
final String name;
const City(this.name);
#override
String toString() => 'City { name: $name }';
}
class CitySearch extends SearchDelegate<City> {
final Bloc<CitySearchEvent, CitySearchState> cityBloc;
CitySearch(this.cityBloc);
#override
List<Widget> buildActions(BuildContext context) => null;
#override
Widget buildLeading(BuildContext context) {
return IconButton(
icon: BackButtonIcon(),
onPressed: () {
close(context, null);
},
);
}
#override
Widget buildResults(BuildContext context) {
cityBloc.add(CitySearchEvent(query));
return BlocBuilder(
bloc: cityBloc,
builder: (BuildContext context, CitySearchState state) {
if (state.isLoading) {
return Center(
child: CircularProgressIndicator(),
);
}
if (state.hasError) {
return Container(
child: Text('Error'),
);
}
return ListView.builder(
itemBuilder: (context, index) {
return ListTile(
leading: Icon(Icons.location_city),
title: Text(state.cities[index].name),
onTap: () => close(context, state.cities[index]),
);
},
itemCount: state.cities.length,
);
},
);
}
#override
Widget buildSuggestions(BuildContext context) => Container();
}
class CitySearchEvent {
final String query;
const CitySearchEvent(this.query);
#override
String toString() => 'CitySearchEvent { query: $query }';
}
class CitySearchState {
final bool isLoading;
final List<City> cities;
final bool hasError;
const CitySearchState({this.isLoading, this.cities, this.hasError});
factory CitySearchState.initial() {
return CitySearchState(
cities: [],
isLoading: false,
hasError: false,
);
}
factory CitySearchState.loading() {
return CitySearchState(
cities: [],
isLoading: true,
hasError: false,
);
}
factory CitySearchState.success(List<City> cities) {
return CitySearchState(
cities: cities,
isLoading: false,
hasError: false,
);
}
factory CitySearchState.error() {
return CitySearchState(
cities: [],
isLoading: false,
hasError: true,
);
}
#override
String toString() =>
'CitySearchState {cities: ${cities.toString()}, isLoading: $isLoading, hasError: $hasError }';
}
class CityBloc extends Bloc<CitySearchEvent, CitySearchState> {
#override
CitySearchState get initialState => CitySearchState.initial();
#override
void onTransition(Transition<CitySearchEvent, CitySearchState> transition) {
print(transition.toString());
}
#override
Stream<CitySearchState> mapEventToState(CitySearchEvent event) async* {
yield CitySearchState.loading();
try {
List<City> cities = await _getSearchResults(event.query);
yield CitySearchState.success(cities);
} catch (_) {
yield CitySearchState.error();
}
}
Future<List<City>> _getSearchResults(String query) async {
// Simulating network latency
await Future.delayed(Duration(seconds: 1));
return [City('Chicago'), City('Los Angeles')];
}
}
A reference for the code above is available at this Github Gist link
https://gist.github.com/felangel/11769ab10fbc4076076299106f48fc95