dart

问题 I have the following function which extracts order data from Db for each user. My goal is to print each user's orders. However, I am getting some weird errors. Here's the function: Future<void> fetchAllOrders() async { final url = 'https://tb-936.firebaseio.com/orders.json?auth=$authToken'; final response = await http.get(url); final List<OrderItem> loadedOrders = []; final extractedData = json.decode(response.body) as Map<String, dynamic>; print('Extracted data is ' + extractedData.toString(

问题 I have a Cloud Firebase database with a questions collection. Each question has a list of map options . I'm using Flutter and have the following classes for question and option : class Question { final String text; final List<Option> options; // I have tried changing this to List<dynamic> but it doesn't help final String reference; Question(this.text, this.options, this.reference); Question.fromMap(Map<String, dynamic> map, {this.reference}) : text = map['text'], options = map['options']; //

问题 I have a Cloud Firebase database with a questions collection. Each question has a list of map options . I'm using Flutter and have the following classes for question and option : class Question { final String text; final List<Option> options; // I have tried changing this to List<dynamic> but it doesn't help final String reference; Question(this.text, this.options, this.reference); Question.fromMap(Map<String, dynamic> map, {this.reference}) : text = map['text'], options = map['options']; //

问题 i have 3 Lists, for example: List l1 = [1, 2, 3, 55, 7, 99, 21]; List l2 = [1, 4, 7, 65, 99, 20, 21]; List l3 = [0, 2, 6, 7, 21, 99, 26]; and i expect the common elements: // [7,99,21] here is what i've tried but didn't work correctly: List l1 = [1, 2, 3, 55, 7, 99, 21]; List l2 = [1, 4, 7, 65, 99, 20, 21]; List l3 = [0, 2, 6, 7, 21, 99, 26]; List common = l1; l2.forEach((element) { l3.forEach((element2) { if (!common.contains(element) || !common.contains(element2)) { common.remove(element);

问题 i have 3 Lists, for example: List l1 = [1, 2, 3, 55, 7, 99, 21]; List l2 = [1, 4, 7, 65, 99, 20, 21]; List l3 = [0, 2, 6, 7, 21, 99, 26]; and i expect the common elements: // [7,99,21] here is what i've tried but didn't work correctly: List l1 = [1, 2, 3, 55, 7, 99, 21]; List l2 = [1, 4, 7, 65, 99, 20, 21]; List l3 = [0, 2, 6, 7, 21, 99, 26]; List common = l1; l2.forEach((element) { l3.forEach((element2) { if (!common.contains(element) || !common.contains(element2)) { common.remove(element);

问题 I am trying to figure out the difference between onEdittingComplete and onSubmitted , I don't know when the latter should be used since the former can be used to switch focus or to submit the content of the form. I tried looking into the documentation but there is not much said about the onSubmitted property. 回答1: onSubmitted: final ValueChanged<String> onSubmitted It returns the TextField entered value in onSubmitted callback, most of the time its used for next/previous field button of

问题 I am trying to figure out the difference between onEdittingComplete and onSubmitted , I don't know when the latter should be used since the former can be used to switch focus or to submit the content of the form. I tried looking into the documentation but there is not much said about the onSubmitted property. 回答1: onSubmitted: final ValueChanged<String> onSubmitted It returns the TextField entered value in onSubmitted callback, most of the time its used for next/previous field button of

问题 I am trying to figure out the difference between onEdittingComplete and onSubmitted , I don't know when the latter should be used since the former can be used to switch focus or to submit the content of the form. I tried looking into the documentation but there is not much said about the onSubmitted property. 回答1: onSubmitted: final ValueChanged<String> onSubmitted It returns the TextField entered value in onSubmitted callback, most of the time its used for next/previous field button of

问题 I am trying to figure out the difference between onEdittingComplete and onSubmitted , I don't know when the latter should be used since the former can be used to switch focus or to submit the content of the form. I tried looking into the documentation but there is not much said about the onSubmitted property. 回答1: onSubmitted: final ValueChanged<String> onSubmitted It returns the TextField entered value in onSubmitted callback, most of the time its used for next/previous field button of

问题 I am trying to figure out the difference between onEdittingComplete and onSubmitted , I don't know when the latter should be used since the former can be used to switch focus or to submit the content of the form. I tried looking into the documentation but there is not much said about the onSubmitted property. 回答1: onSubmitted: final ValueChanged<String> onSubmitted It returns the TextField entered value in onSubmitted callback, most of the time its used for next/previous field button of