[Flutter] 에러 해결

210627

1. Target of URI doesn't exist 'package:english_words/english_words.dart'관련 에러

참고 https://stackoverflow.com/questions/51809899/target-of-uri-doesnt-exist-packageenglish-words-english-words-dart

=> flutter pub get과 flutter packages get은 동일하다

2. 사진 첨부 시 에러

사진 첨부 방법
-> 사진을 넣을 파일 생성
-> pubspec.yaml 수정

flutter:
  uses-material-design: true
  assets:
    - assets/soongsil.jpg

띄어쓰기, 들여쓰기 잘하기!!!!!!!!!
(엔터)assets:
(엔터)-(공백)assets/파일명.jpg

3. 객체 선언시 괄호 주의

var list = const [
    ['Let It Go', 'Idina Menzel'],
    ['Hakuna Matata', 'Nathan Lane'],
    ['A Whole New World', 'Naomi Scott'],
    ['Under the Sea', 'Samuel E. Wright'],
    ['Prince Ali', 'Will Smith'],
    ['Youve got a friend in me','Randy Newman'],
    ['Beauty and the Beast', 'Ariana Grande & john Legend'],
    ['Speechless', 'Naomi Scott']
  ];

{'let it go','idina menzel'}, {}썼다가 에러남

---

210630

4.api-get 관련 에러

https://github.com/dart-lang/http/issues/536

초기에 잘못작성한 코드

final response= await http.get(Uri.https('www.google.com', '/get/'));

수정

final url=Uri.parse('https://dapi.kakao.com/v3/search/book?target=title&query=doit; 
var response=await http.get(url,
              headers: {"Authorization":"KakaoAK ##비밀"});
          

4-1.Json 파싱 관련

https://muhly.tistory.com/84?category=926046

5.null safety 관련 에러

https://stackoverflow.com/questions/66648374/how-to-migrate-code-to-null-safety-in-dart

---

210701

6. The method '[]' can't be unconditionally invoked because the receiver can be 'null'.

전

children: <Widget>[
              Image.network(
                routeArgs['thumbnail'],
                height:100,
                width:100,
                fit:BoxFit.contain
              ),
            ],

후

(routeArgs as dynamic)['thumbnail'],

https://fileidea.com/2021/05/05/method-cant-be-unconditionally-invoked-because-the-receiver-can-be-null-with-firestore/

https://dart.dev/tools/diagnostic-messages#unchecked_use_of_nullable_value

7. provider 소비관련

이런식으로 접근했을때 접근이 불가능 했음

context.watch<DisplayList>().items[index]['title']

수정 후

var item =context.watch<DisplayList>().items; //선언하고
Text(item[index]['authors'].toString()) //접근성공

이유는 아직도 모름 😂

0709
flutter web으로 안켜지는 에러
https://flutter.dev/docs/development/ui/navigation/url-strategies