I'm new in flutter and i'm trying to get list in list view. I searched a lot on this but i did not find something. Exception occurs when i'm trying to cast response of API and list view shows nothing.
Exception:
Exception: NoSuchMethodError: Class '_InternalLinkedHashMap<String, dynamic>' has no instance method 'map' with matching arguments.
I/flutter (21020): Receiver: _LinkedHashMap len:2
I/flutter (21020): Tried calling: map<Post>(Closure: (dynamic) => Post)
I/flutter (21020): Found: map<K2, V2>((K, V) => MapEntry<K2, V2>) => Map<K2, V2>
final response = await client.get('http:url');
return compute(parsePosts, response.body);
}
List<Post> parsePosts(String responseBody) {
final parsed = json.decode(responseBody).cast<Map<String, dynamic>>();
return parsed.map<Post>((json) => Post.fromJson(json)).toList();
}
My JSON is like that
{
"status": "1",
"category": [
"Artificial Intelligence",
"big data",
"Cyber Security",
"Data Science",
"Software Development"
]
}
I want to show a list data in list view in Flutter. If you have any query or something regarding code then can ask me. Hope I will get best solution from this community.
Thanks in advance.
Related
Help me pls.
I have this error.
10Q
Unhandled Exception: NoSuchMethodError: Class 'FirebaseAuthException' has no instance getter '_message'.
E/flutter ( 5700): Receiver: Instance of 'FirebaseAuthException'
E/flutter ( 5700): Tried calling: _message
await _auth
.signInWithEmailAndPassword(
email: _emailTextEditingController.text.trim(),
password: _passwordTextEditingController.text.trim(),
)
.then((authUser) {
setState(() {
firebaseUser = authUser.user;
});
}).catchError((error) {
showDialog(
context: context,
builder: (c) {
return ErrorAlertDialog(
message: error._message == '[firebase_auth/user-not-found] There is no user record corresponding to this identifier. The user may have been deleted.'
? 'Email or password incorrect' : 'Error',
);
});
});
error._message == '[firebase_auth/user-not-found] There is no user record corresponding to this identifier. The user may have been deleted.'
? 'Email or password incorrect' : 'Error',
You are being told that there is no getter named _message for FirebaseAuthException. If you go to the code for that class, or the documentation (here) and look at the methods you have available to you,
_message is not one.
There is one there (getErrorCode) that you should be able to compare with much easier.
I think that the _message was called on null, I am not sure about this.
I want to show videos on my channel with youtube api.
define videos: List? videos;
Here is the method with video listings:
factory VideosList.fromJson(Map<String, dynamic> json) => VideosList(
kind: json["kind"],
etag: json["etag"],
nextPageToken: json["nextPageToken"],
videos: List<VideosList>.from(
json["items"].map((x) => VideosList.fromJson(x))),
pageInfo: PageInfo.fromJson(json["pageInfo"]),
);
The error it gives when I run the application is: Unhandled Exception: NoSuchMethodError: The method 'map' was called on null.
The line with the error:
videos: List<VideosList>.from(json["items"].map((x) => VideosList.fromJson(x))),
videos: List<VideosList>.from(json["items"].map((x) => VideosList.fromJson(x))).toList(),
I tried converting map to list it didn't work.
My razor pay coding
final prefs = await SharedPreferences.getInstance();
final options = {
"description": 'Thanks for placing order!',
"image": baseImage,
"currency": "INR",
"key": " rzp_live_vwdPSYlBoyrXul", // your Key Id from Razorpay dashboard
"amount": total_amt,
"name": 'Good way',
"prefill": {
"email": '',
"contact": prefs.getString("user_name"),
"name": ''
},
};
_razorpay.open(options);
If i click pay
Unhandled Exception: NoSuchMethodError: The method 'open' was called on null it coming like this
Well, as the error says you are trying to call the method "open" on a variable which has null as value.
You need to debug where and how you define the _razorpay variable, it might get stuck somwhere, or you just forgot to define/instantiate it
_razorpay can be null here.
on Your pay button you can check if _razorpay is null or has value.
if(_razorpay != null) {
//Procced to pay
}
I am trying to generate a response from my chatbot(using dialogflow)
void response(query) async {
AuthGoogle authGoogle = await AuthGoogle(
fileJson: "Assets/amigo-pyhyyy-e2d1db5e1ee9.json").build();
Dialogflow dialogflow = await Dialogflow(
authGoogle: authGoogle, language: Language.english);
AIResponse aiResponse = await dialogflow.detectIntent(query);
setState(() {
messages.insert(0, {"data": 0,
"message": aiResponse.getListMessage()[0]["text"]["text"][0].tostring()
});
});
I get this error:
E/flutter ( 8166): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: NoSuchMethodError: Class 'String' has no instance method 'tostring'.
I tried adding dependencies in the pubspec.yaml:
dependencies:
to_string: ^1.2.1
dev_dependencies:
to_string_generator: ^1.2.1
but instead of getting a reply from the bot on the app, I am still getting a reply on my console.
Please have a look.
OKAYYYYY! I did change all of the instances to .toString() , instead of .tostring() (That was so stupid of me...- __________-)
But now I have an error:
════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
The following assertion was thrown building:
type 'String' is not a subtype of type 'Widget'
Looking at the error message, aiResponse.getListMessage()[0]["text"]["text"][0] already returns a String value, so you can remove tostring() Lik Almasfiza already mentioned, normally it's toString() with a capital S, but should not be needed to convert a String to a String.
I'm trying to athenticate using APIs from a flutter app but i get these errors everytime i click Login Button
final resp = await http.post("http://192.168.73.5/myserv/login.php", body: {
"login": "login",
"apid": "re0b53fd92d4b1593db1880az322d66ea9d4",
"email": _email,
"pass": _password,
});
var __data =json.decode(resp.body);
if (__data.length == 0) {
final snackbar = SnackBar(
content: Text('Server error'),
);
scaffoldKey.currentState.showSnackBar(snackbar);
} else if (__data[0]['resp'] == 'error') {
final snackbar = SnackBar(
content: Text('Password or email is incorrect!'),
);
scaffoldKey.currentState.showSnackBar(snackbar);
} else if (__data[0]['resp'] == 'sucess') {
final snackbar = SnackBar(
content: Text('You are logged in'),
);
scaffoldKey.currentState.showSnackBar(snackbar);
Navigator.of(context)
.pushReplacement(MaterialPageRoute(builder: (context) => HomeApp()));
}
}
══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (29517): The following NoSuchMethodError was thrown while finalizing the widget tree:
I/flutter (29517): The method 'cancel' was called on null.
I/flutter (29517): Receiver: null
I/flutter (29517): Tried calling: cancel()
I/flutter (29517): When the exception was thrown, this was the stack:
My suggestion would be to take a look to your dispose method. There you might notice a statement calling a cancel method on something that was never initiated or used, only declared. In my case I got this error because at the disposed method I was trying to cancel a subscription to a Firebase service that I had not used. I never attached a listener to it, therefore when trying to cancel it, Flutter complained saying "the method cancel was called on null". I deleted the unnecessary line at dispose method and the error resolved. Hope the explanation helps somebody.