java - 无法使用 FirebaseRecyclerAdapter 将 Firebase JSON 转换为 Java 对象

Question

我有两项 Activity ，一项用于创建评估对象，另一项用于列出 Firebase 中的评估对象，但是我遇到了一个问题:POJO 能够很好地序列化为 JSON，但是 FirebaseRecyclerAdapter似乎无法将JSON数据返回到对象类型。

这是我的目标文件:

@IgnoreExtraProperties
public class Assessment {

private String company;
private String industry;
private String location;
private String product;
private String ownerId;
private String ownerName;
private boolean isDraft;
private boolean isQuickWalk;
private Map<String, Category> categories;



public Assessment() {
    // Default constructor required for calls to DataSnapshot.getValue()
}

public Assessment(String companyName, String industryName, String locationName,
                  String productName, String ownerId, String ownerName, boolean isDraft, boolean isQuickWalk, Map<String, Category> categories) {
    this.company = companyName;
    this.industry = industryName;
    this.location = locationName;
    this.product = productName;
    this.ownerId = ownerId;
    this.ownerName = ownerName;
    this.isDraft = isDraft;
    this.isQuickWalk = isQuickWalk;
    this.categories = categories;
}

public String getCompanyName() {
    return company;
}

public String getIndustryName() {
    return industry;
}

public String getLocationName() {
    return location;
}

public String getProductName() {
    return product;
}

public String getOwnerName() {
    return ownerName;
}

public boolean getIsDraft() {
    return isDraft;
}

public boolean getIsQuickWalk() {
    return isQuickWalk;
}

基于此，我使用此代码写入 Firebase，一切正常:

String key = mDatabaseRef.child(FIREBASE_ASSESSMENTS).push().getKey();
Assessment assessment = new Assessment(editCompanyText, editLocationText,
                        editIndustryText, editProductText, uid, 
currentUser.getEmail(), isDraft, isQuickWalk, null);

Map<String, Object> childUpdates = new HashMap<>();
                childUpdates.put("/" + FIREBASE_ASSESSMENTS + "/" + key, 
assessment);
mDatabaseRef.updateChildren(childUpdates);

但是，当我尝试从数据库中读取时，我相信这就是问题所在:

FirebaseRecyclerAdapter<Assessment, ViewDraftsViewHolder> adapter;
    mRecyclerView = (RecyclerView) findViewById(R.id.draft_recycler_view);
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

    Query query = mEvalRef;
    FirebaseRecyclerOptions<Assessment> options = new FirebaseRecyclerOptions.Builder<Assessment>()
            .setQuery(query, Assessment.class)
            .build();

    adapter = new FirebaseRecyclerAdapter<Assessment, ViewDraftsViewHolder>(options) {
        @Override
        protected void onBindViewHolder(ViewDraftsViewHolder holder, int position, Assessment model) {
            if(model.getIsDraft()) {
                holder.companyName.setText(model.getCompanyName());
                holder.industryName.setText(model.getIndustryName());
                holder.locationName.setText(model.getLocationName());
                holder.productName.setText(model.getProductName());
                holder.ownerName.setText(model.getOwnerName());

                if(model.getIsQuickWalk()) {
                    holder.isQuickWalk.setText("Quick Walkthrough");
                } else {
                    holder.isQuickWalk.setText("Full Questionnaire");
                }
            }

        }

        @Override
        public ViewDraftsViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.completed_and_drafts_list_item, parent, false);
            return new ViewDraftsViewHolder(view);
        }
    };

    mRecyclerView.setAdapter(adapter);

    private static class ViewDraftsViewHolder extends RecyclerView.ViewHolder {
    TextView companyName;
    TextView industryName;
    TextView locationName;
    TextView productName;
    TextView ownerName;
    TextView isQuickWalk;

    public ViewDraftsViewHolder(View itemView) {
        super(itemView);

        companyName = (TextView) itemView.findViewById(R.id.companyView);
        industryName = (TextView) itemView.findViewById(R.id.industryView);
        locationName = (TextView) itemView.findViewById(R.id.locationView);
        productName = (TextView) itemView.findViewById(R.id.productView);
        ownerName = (TextView) itemView.findViewById(R.id.ownerName);
        isQuickWalk = (TextView) itemView.findViewById(R.id.isQuickWalkView);
    }
}

我不太确定 FirebaseRecyclerAdapter 哪里出错了无法将数据转换回Assessment目的。我没有正确设置对象吗？我是否没有正确设置 RecyclerAdapter？这是数据在 Firebase 中的样子

"-KzB39l1KH6MyEsgr6Ke" : {
  "companyName" : "testing ",
  "industryName" : "at",
  "isDraft" : true,
  "isQuickWalk" : true,
  "locationName" : "five fifteen",
  "ownerName" : "test@email.com",
  "productName" : "please ignore"
},

您能给我的任何帮助都会非常好，几天来我一直在努力解决这个问题。谢谢!!

Answer 1

在这一行:

  Query query = mEvalRef;

我假设 mEvalRef 是一个数据库引用，您可以显示它吗，因为不清楚如何从数据库查询数据。

只需添加(mEvalRef)，即可发现问题。

编辑

在您的(评估)类中，我注意到变量没有 setter 方法，请为类中的每个变量添加 setter 方法，看看这是否有帮助。

编辑2

在您尝试读取值的代码中。

删除这个

    FirebaseRecyclerOptions<Assessment> options = new FirebaseRecyclerOptions.Builder<Assessment>()
        .setQuery(query, Assessment.class)
        .build();

在适配器初始化的这一行或部分中:

   adapter = new FirebaseRecyclerAdapter<Assessment, ViewDraftsViewHolder>(options)

删除(options)参数并将上面的代码行更改为:

      adapter = new FirebaseRecyclerAdapter<Assessment, ViewDraftsViewHolder>(Assessment.class, R.layout.completed_and_drafts_list_item, ViewDraftsViewHolder.class, query )

接下来删除此代码:

        @Override
    public ViewDraftsViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.completed_and_drafts_list_item, parent, false);
        return new ViewDraftsViewHolder(view);
    }

最后将(私有(private))更改为(公共(public)):

    private static class ViewDraftsViewHolder extends RecyclerView.ViewHolder {

并且不要忘记在评估类中保留变量的 setter 并将变量公开，正如我告诉你的那样。

编辑3

现在忘记 EDIT 2 并按照最初的方式重新输入代码，并在配置完所有内容后执行此操作:

在初始化适配器的方法中，在此之前添加:

   mRecyclerView.setAdapter(adapter);

这个:

   adapter.startListening();