Adding elements to List in Flutter from For statement?
21,108
You are not instantiating your searchIds object. add this
List searchIds = new ArrayList<>();
(Or)
List searchIds = new List();
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Charles Jr
Jack of All Trades - Master of Few!! Started with Obj-C.then(Swift)!.now(Flutter/Dart)! Thank everyone for every answer, comment, edit, suggestion. Can't believe I've been able to answer a few myself :-)
Updated on April 26, 2020Comments
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Charles Jr almost 4 years
I'm receiving the following error while trying to add elements from my for loop to my
List
...NoSuchMethodError: The method 'addAll' was called on null. Receiver: null Tried calling: addAll("LrWr826cd3Y")
Here is my code...
Future getData() async { //Map videoId; String url = 'https://Youtube API'; var httpClient = createHttpClient(); var response = await httpClient.read(url); Map data = JSON.decode(response); var videos = data['items']; //returns a List of Maps List searchTitles; List searchIds; List searchImages; for (var items in videos) { //iterate over the list Map myMap = items; //store each map final video = (myMap['id'] as Map); print(video['videoId']); searchIds.addAll(video['videoId']); final details = (myMap['snippet'] as Map); final videoimage = (details['thumbnails'] as Map); final medium = (videoimage['medium'] as Map); } setState(() { }); if (!mounted) return; }
print(video['videoId']);
successfully lists the 3 Youtube video ids as Strings.searchIds.addAll(video['videoId']);
throws the error. I've tried bothsearchIds.add
andsearchIds.addAll
. Where am I going wrong?I would like to eventually push these lists to my List class here..
class CardInfo { //Constructor List id; List title; List video; CardInfo.fromJson(List json) { this.id; this.title; this.video; } }
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Charles Jr over 6 yearsThis is how I got it to work for Flutter...
List searchIds = new List();
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milad zahedi over 6 yearsI see your problem is fixed. Good job.
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Gowthaman M almost 5 yearsList searchIds = new List(); this is worked for me.
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poonam kalra almost 3 yearsYou can also use List searchIds = [];