Hello Readers I am new in flutter and i want to do pagination, for pagination I am using one package which name is "pull to refersh".
Problems :
I have total 6 post and per page limits are 3.
1)When I reached at the end of list then api will call and set current page variable value is 2 and it will load all data of page 2 as a new list, but i want to merge page 2 data into same list... (Pagination like facebook instagram etc).
2)My another problem is when i pull for refersh, page is refersh perfectly and it will go to the first page but problem is, when i again go at the end of list it shows me no more data(which means page 2 api is not working)
I have one condition like if else:- "hasNextPage" this variable getting from api and the response is 1 or 2, if response is 1 then there further page after current page and if is 0 then there is no page after current page.
I am posting my code and api link also can you please help me.
Method for get data from API
int currentPage = 1;
bool isRefersh = false;
final RefreshController refreshController = RefreshController();
Future<UserPost> getUserPost() async {
var url =
"LINK=$currentPage";
var response = await http.get(Uri.parse(url));
var jsondata = jsonDecode(response.body.toString());
var _apiData = UserPost.fromJson(jsondata);
if (response.statusCode == 200) {
print("******getUserPost API");
print("current page****$currentPage");
print("hasnext page ${_apiData.hasNextPage}");
print(jsondata);
if(isRefersh == true){
setState((){
//currentPage = 1;
isRefersh = false;
});
refreshController.refreshCompleted();
return UserPost.fromJson(jsondata);
}
else{
print("//////////////// has next page");
print(_apiData.hasNextPage.toString());
if(_apiData.hasNextPage == 0){
refreshController.loadNoData();
return UserPost.fromJson(jsondata);
}else{
}
return UserPost.fromJson(jsondata);
}
} else {
return UserPost.fromJson(jsondata);
}
}
Method for pull to Refersh
onRefresh: () async{
await Future.delayed(Duration(milliseconds: 1000));
setState(() {
isRefersh = true;
currentPage = 1;
});
},
Method for Pagination
onLoading: () async {
if(snapshot.data!.hasNextPage == 0){
refreshController.loadNoData();
}else{
setState(() {
currentPage++;
});
await Future.delayed(Duration(milliseconds: 1000));
refreshController.loadComplete();
}
},
I Hope it's help you
try this way :-
final RefreshController refreshController =
RefreshController(initialRefresh: true);
Future<bool> getPassengerData({bool isRefresh = false}) async {
if (isRefresh) {
currentPage = 1;
} else {
if (currentPage >= totalPages) {
refreshController.loadNoData();
return false;
}
}
final Uri uri = Uri.parse(
"api url=$currentPage&size=10");
final response = await http.get(uri);
if (response.statusCode == 200) {
final result = passengersDataFromJson(response.body);
if (isRefresh) {
passengers = result.data;
}else{
passengers.addAll(result.data);
}
currentPage++;
totalPages = result.totalPages;
print(response.body);
setState(() {});
return true;
} else {
return false;
}
}
Method for pull to Refersh
onRefresh: () async {
final result = await getPassengerData(isRefresh: true);
if (result) {
refreshController.refreshCompleted();
} else {
refreshController.refreshFailed();
}
},
Method for onLoading:
onLoading: () async {
final result = await getPassengerData();
if (result) {
refreshController.loadComplete();
} else {
refreshController.loadFailed();
}
},
Try this way.
when you get the response in second page just create new list with previous list.
i.e var newData = [...?dummyData.data, ...?_apiData.data];
than return this same list.
UserPostModel dummyData = UserPostModel();
Future<UserPostModel> getUserPost() async {
var url =
"*****?page=$currentPage";
var response = await http.get(Uri.parse(url));
var jsondata = jsonDecode(response.body.toString());
var _apiData = UserPostModel.fromJson(jsondata);
var newData = [...?dummyData.data, ...?_apiData.data];
//totalPage = _apiData.totalPages as int?;
if (response.statusCode == 200) {
if (isRefersh == true) {
setState(() {
isRefersh = false;
});
refreshController.refreshCompleted();
} else {
if (_apiData.hasNextPage == 0) {
refreshController.loadNoData();
} else {
refreshController.loadComplete();
}
}
dummyData.data = newData;
return dummyData;
} else {
return dummyData;
}
}
Related
Does anyone know how to adjust the QR code scanner speed? since the second scan is so quick,
source example is down below, you can download it add and run it in your Flutter project to test!
What are the differenceis are in the controller.scannedDataStream.listen() function. I posted down below:
Barcode? result;
var qrText = "";
bool isValid = false;
bool isExpired = false;
QRViewController? controller;
controller.scannedDataStream.listen((scanData) async {
log(scanData.code);
if (!scanData.code.contains('?key=')) {
setState(() {
qrText = "This is not a correct code";
isValid = false;
});
} else {
var key_hash = scanData.code.split('?key=');
log('hash: ' + key_hash[1]);
await decrypt(key_hash[1]).then((String result) async {
if (result == "") {
log('result: ' + result);
await controller.stopCamera();
setState(() {
qrText = result;
isValid = true;
isExpired = true;
});
}
else {
log('result: ' + result);
await controller.pauseCamera();
await controller.stopCamera();
setState(() {
qrText = result;
isValid = true;
isExpired = false;
});
}
});
}
});
https://pub.dev/packages/qr_code_scanner/example
I'm trying to set up Auth0 for my Flutter app from this demo, but I ran into this issue. I've only been using Flutter for a little while, and I fixed a few errors, but can't fix this one. I checked for other answers here, and tried the documentation too. The error message is;
The operator [] isn't defined for 'Future<Map<String,Object>> Function(String)'
This is the method with the error;
Future<void> loginAction() async {
setState(() {
isBusy = true;
errorMessage = '';
});
try {
final AuthorizationTokenResponse? result =
await appAuth.authorizeAndExchangeCode(
AuthorizationTokenRequest(
AUTH0_CLIENT_ID,
AUTH0_REDIRECT_URI,
issuer: 'https://$AUTH0_DOMAIN',
scopes: ['openid', 'profile', 'offline_access'],
promptValues: ['login']
),
);
Map<String, Object> parseIdToken(String idToken) {
final parts = idToken.split(r'.');
assert(parts.length == 3);
return jsonDecode(
utf8.decode(base64Url.decode(base64Url.normalize(parts[1]))));
}
Future<Map<String, Object>> getUserDetails(String accessToken) async {
final url = 'https://$AUTH0_DOMAIN/userinfo';
final response = await http.get(Uri.parse(
url,
));
if (response.statusCode == 200) {
return jsonDecode(response.body);
} else {
throw Exception('Failed to get user details');
}
}
await secureStorage.write(
key: 'refresh_token', value: result!.refreshToken);
setState(() {
isBusy = false;
isLoggedIn = true;
name = parseIdToken['name'];
picture = getUserDetails['picture'];
});
} catch (e, s) {
print('login error: $e - stack: $s');
setState(() {
isBusy = false;
isLoggedIn = false;
errorMessage = e.toString();
});
}
}
And the lines that are erroring are;
name = parseIdToken['name'];
picture = getUserDetails['picture'];
Can this be fixed?
getUserDetails is a function, and so it doesn't have a [] operator.
Instead, try: var userDetails = await getUserDetails("token..."); picture = userDetails["picture"];
I am using a provider package. I want to display a loading spinner while waiting for a request to complete. The pattern below is too verbose. Please help me make it less verbose. Here is my code
class APIService with ChangeNotifier {
// Check for working API backend
bool isWorking = false;
bool isLoading = false;
set _isLoading(bool value) {
isLoading = value; <--
notifyListeners();
}
Future<bool> selectAPI(String input) async {
_isLoading = true; <-- 1
final uri = Uri.tryParse('https://$input$url')!;
final response = await http.get(uri);
if (response.statusCode == 200) {
final body = jsonDecode(response.body) as Map<String, dynamic>;
bool isTrue = body['info']['title'] == 'SamFetch';
_isLoading = false; <-- 2
notifyListeners();
return isWorking = isTrue;
}
_isLoading = false; <-- 3
throw response;
}
}
Here is my UI code
IconButton(
icon: apiService.isLoading
? CircularProgressIndicator()
: Icon(Icons.done),
onPressed: () async {
await addAPI(apiService, cache);
}),
}
Below is addAPI() method
Future<void> addAPI(APIService apiService, Cache cache) async {
if (api != null) {
try {
await apiService.selectAPI(api!);
if (apiService.isWorking) {
await cache.saveAppName(api!);
}
} on SocketException catch (e) {
print(e);
} catch (e) {
await cache.clearCache();
}
}
}
Is setState the final solution?
You can use Future Builder and set your Future Function in future attribute. You can control the visible widget based on the status of your function. So you dont have to use isloading variable.
I have this method to feed my list, but with it i'm not able to change items dynamically ( add items, drop it...) :
loadLab(String submenu, [int limit]) async {
var parts = submenu.split('/');
var pathSlashless = parts[0].trim();
var subPathSlashless = parts.sublist(1).join('/').trim();
var snapshot = await _storage.ref().child("/${submenu}");
var retorno = await snapshot.listAll();
List<ItemLab> conteudo = [];
if(subPathSlashless.isEmpty || subPathSlashless == null){
retorno.prefixes.forEach((element) {
conteudo.add(
ItemLab(
tipo: 'PASTA',
elemento: element,
),
);
});
}
if(limit != null){
if(conteudo.length > limit){
hasMore = true;
return Stream.value(conteudo);
}else{
hasMore = false;
print("menor quen ove");
}
}
}
try {
if(subPathSlashless.isNotEmpty){
print(subPathSlashless);
List items;
await databaseReference
.collection("lab_${pathSlashless}_url")
.snapshots().forEach((element) {
element.docs.forEach((f) {
if(f.data()['videos'] != null){
items == null ? items = f.data()['videos'] :
items.addAll(f.data()['videos']);
};
print("ITEMS :::: >>> ${items}");
});
});
}catch(e){
print(e);
}
pathSlashless = null;
subPathSlashless = null;
conteudo = checkDuplicateFolder(conteudo, submenu);
print(conteudo);
return Stream.value(conteudo);
}
and the list>
return StreamBuilder(
stream: ctrlLab.loadLab(submenu),
throw this error:
type 'Future' is not a subtype of type 'Stream'
What I need to do to Make the return a Stream instead of a Future
i have been trying to get all my data from a sqflite database, when i try to get a single data, this works totally fine:
Future<dynamic> getUser() async {
final db = await database;
var res = await db.query("files");
if (res.length == 0) {
return null;
} else {
var resMap = res[0];
return resMap;
}
}
but when i try to get all data using a for loop like the example below, i get an error
Future<dynamic> getUser() async {
final db = await database;
var res = await db.query("files");
var resMap;
var count = res.length;
if (count != 0) {
for (int i = 0; i < count; i++) {
resMap.add(res[i]);
}
}
return resMap;
}
the error says:
The method 'forEach' was called on null.
Receiver: null
Tried calling: forEach(Closure: (dynamic, dynamic) => Null)
i understand that it says that I've got no data,
and i also tried to remove the if statement, but still no luck!
change this method:
EDIT
Future<List<Map>> getUser() async {
final db = await database;
var res = await db.query("files");
List<Map> resMap = [];
if (res != null res.length > 0) {
for (int i = 0; i < count; i++) {
resMap.add(res[i]);
}
return resMap;
} else
{
return null;
}
}
try this in you widget
List<Map> newUser = [];
#override
void initState() {
super.initState();
getUser();
}
getUser() async {
final _userData = await DBProvider.db.getUser();
if(_userData != null ){
setState(() {
newUser = _userData;
});
} else{
setState(() {
newUser =[];
});
}
}