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我在這裏使用接口時遇到問題。當我嘗試設置列表中的「答案」到一個ArrayList我得到的錯誤:使用列表接口,其中給出的類型是要通過setter方法實現的接口
的方法setAnswers(列表)在類型QuestionImpl不適用於參數(ArrayList的)
對我來說,似乎我想在這種情況下使用接口,以便稍後可以指定實現。
public class QuestionImpl extends QuestionAnswerImpl implements Comparable<Object>, Question {
private List<Answer> answers;
public QuestionImpl(){
setAnswers(new ArrayList<AnswerImpl>());
}
@Override
public void setAnswers(List<Answer> answers) {
this.answers = answers;
}
@Override
public List<Answer> getAnswers() {
// TODO Auto-generated method stub
return answers;
}
答接口:
public interface Answer {
int i=0;
public int compareTo(Object object1);
public String getListValu(int question);
public void setNum(int i);
}
Answer class info (most of the code is irrelevant here)
public class AnswerImpl extends QuestionAnswerImpl implements
Comparable<Object>, Answer {...}
變化'setAnswers(新的ArrayList());'(所以''而非'') –