安卓无法序列化Hashmap、java。伊奥。NotSerializableException

Question

public class Common implements Serializable{

    private static HashMap<Integer,List<LevelList>> levelListMap = new HashMap<>();

    public static Map<Integer, List<LevelList>> getLevelListMap(Context context) {

        File file = new File(context.getDir("data", MODE_PRIVATE), "map");
        ObjectInputStream inputStream = null;
        try {
            inputStream = new ObjectInputStream(new FileInputStream(file));
            levelListMap = (HashMap<Integer, List<LevelList>>) inputStream.readObject();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return levelListMap;
    } ...
}

我无法序列化hashmap。我一直得到java.io.NotSerializableException levelListMap = (HashMap<Integer, List<LevelList>>) inputStream.readObject();

public class LevelList implements Serializable{

    public int id;
    public String title;
    public String imgurl;
    public String songurl;
    public String songtext;
    boolean isFavourite;

    public void release() {

    }


    public void setFavourite(boolean favourite) {
        isFavourite = favourite;
    }

    public boolean isFavourite(){
        return isFavourite;
    }

}

Answer 1

检查此链接How to serialize a list in Java。列表的标准实现，即ArrayList、LinkedList等可序列化

如果将列表声明为ArrayList<LevelList> levelList = new ArrayList<LevelList>();等列表子类型之一，那么它应该是可即时序列化的。否则，您需要以一种安全的方式进行强制转换，例如按照该应答线程中Theodore Murdock的建议，使用<T extends List<Foo> & Serializable> setFooList(T list)设置列表实现