Inheritance 将值从子类存储到父类
我想知道如何将值从子类存储到父类Inheritance 将值从子类存储到父类,inheritance,hashmap,abstract-class,Inheritance,Hashmap,Abstract Class,我想知道如何将值从子类存储到父类 public class Question { private HashMap<String,ArrayList<String>> mcqHashMap = new HashMap<String,ArrayList<String>>(); //storing question and options of MCQ public ArrayList<String> rankingquestion = n
public class Question {
private HashMap<String,ArrayList<String>> mcqHashMap = new HashMap<String,ArrayList<String>>(); //storing question and options of MCQ
public ArrayList<String> rankingquestion = new ArrayList<String>();
public Scanner scan = new Scanner(System.in);
public ArrayList<String> correctMCQAnswer = new ArrayList<String>(); // will keeps the correct answer of each question
HashMap<String,ArrayList<String>> newmcqHashMap;
public HashMap<String, ArrayList<String>> getMCQQuestionAnswer() {
System.out.println("NEW:" + mcqHashMap);
return this.newmcqHashMap;
}
public void setMCQQuestionAnswer(HashMap<String, ArrayList<String>> mcqQuestionAnswer) {
this.mcqHashMap = mcqQuestionAnswer;
System.out.println("After setting" + this.mcqHashMap);
newmcqHashMap = this.mcqHashMap;
}
}
public class MultipleChoiceQuestion extends Question {
String storeMultipleChoiceQuestion;
ArrayList<String> answersMCQ = new ArrayList<String>();
HashMap<String, ArrayList<String>> mcqQuestionAnswer = new HashMap<String, ArrayList<String>>();
//returns MCQQuestion
public String storeMultipleChoiceQuestion() {
System.out.println("Enter the Multiple question: ");
String MultipleChoiceQuestion = scan.nextLine();
while(MultipleChoiceQuestion.isEmpty()) {
System.out.println("Null in invalid");
MultipleChoiceQuestion = scan.nextLine();
}
return MultipleChoiceQuestion;
}
//creates MCQ Questions with mcq options
public void create() {
String value = storeMultipleChoiceQuestion();
try {
System.out.println("Enter the number of choices for your multiple choice question:");
int numberOfChoices = scan.nextInt();
scan.nextLine();
if(numberOfChoices <= 0) {
System.out.println("Must be greater than 0");
}
else {
for(int i=1; i <= numberOfChoices; i++){
System.out.println("Enter prompt " + i);
String Option = scan.nextLine();
answersMCQ.add(Option);
while(Option.isEmpty()) {
System.out.println("Null in invalid");
Option = scan.nextLine();
}
mcqQuestionAnswer.put(value, answersMCQ);
super.setMCQQuestionAnswer(mcqQuestionAnswer);
//this.mcqHashMap.put(value, answersMCQ);
}
}
}catch (Exception e) {
System.out.println("Exception thrown! Use integer greater than 0.");
}
}
`
没有打印任何东西
我肯定我在什么地方做错了。我在父类中也使用了getter setter,但仍然不走运。所以基本上,问题将存储到mcqHashMap中,我想使用存储的mcqHashMap来显示Survey类的目的
谢谢你的帮助。谢谢没关系,伙计们,我想起来了。谢谢我使受保护的静态而不是受保护的hashmap。糟糕的做法,但工作
谢谢你的帮助。没关系,伙计们,我想出来了。谢谢我使受保护的静态而不是受保护的hashmap。糟糕的做法,但工作
谢谢你的帮助。如果你说这是不打印任何东西,那么可能是
mcqHashMap
是空的吗?很难从你模糊的例子中看出发生了什么我刚刚编辑了更多的细节。谢谢如果你说它根本不打印任何东西,那么可能是mcqHashMap
是空的吗?很难从你模糊的例子中看出发生了什么我刚刚编辑了更多的细节。谢谢
public class Survey extends Question implements Serializable {
MultipleChoiceQuestion mcq = new MultipleChoiceQuestion();
public void Display() {
System.out.println("THis is from get " + this.getMCQQuestionAnswer());
System.out.println("THis is from get mcqhash" + this.newmcqHashMap);
}