如何在ModelView中使用HashMap？

Question

我第一次尝试使用 ViewModel，出现了一个我无法解决的错误。我收到消息 "Cannot resolve put"，我该如何解决这个问题？

public class SharedViewModel 扩展了 ViewModel {

public HashMap<Integer, MutableLiveData<String>> answers = new HashMap<Integer, MutableLiveData<String>>(){
            answers.put(1, new MutableLiveData<String>())
            answers.put(2, new MutableLiveData<String>())
            answers.put(3, new MutableLiveData<String>())
};



public MutableLiveData<String> getAnswer(int questionId) {
    return answers.get(questionId);
}

public void setAnswer(int questionId, String answer) {
    if (answers.get(questionId) != null) {
        answers.get(questionId).setValue(answer);
    }
}
}

Answer 1

public HashMap<Integer, MutableLiveData<String>> answers = new HashMap<Integer, MutableLiveData<String>>();

    public void initValues(){
        answers.put(1, new MutableLiveData<String>())
        answers.put(2, new MutableLiveData<String>())
        answers.put(3, new MutableLiveData<String>())
    }

从 fragment/activity

调用此方法初始化

或者试试这个

public HashMap<Integer, MutableLiveData<String>> answers = new HashMap<Integer, MutableLiveData<String>>() {
        {
            put(1, new MutableLiveData<String>());
            put(2, new MutableLiveData<String>());
            put(3, new MutableLiveData<String>());
        }
    };

Answer 2

而不是这个

public HashMap<Integer, MutableLiveData<String>> answers = new HashMap<Integer, MutableLiveData<String>>(){
        answers.put(1, new MutableLiveData<String>())
        answers.put(2, new MutableLiveData<String>())
        answers.put(3, new MutableLiveData<String>())
};

这样做

public HashMap<Integer, MutableLiveData<String>> answers = new HashMap<Integer, MutableLiveData<String>>(){{
        put(1, new MutableLiveData<String>())
        put(2, new MutableLiveData<String>())
        put(3, new MutableLiveData<String>())
}};