我正在尝试将我的Firebase表/列表的内容称为“资产”显示到回收者视图中。但我收到一条错误消息:
com.google.firebase.database.DatabaseException:无法将java.lang.String类型的对象转换为com.example.zakatone.Assets类型
我试图查看所有关联的类,但是找不到错误。
这是我的数据在Firebase中的外观:
Assets.java
package com.example.zakatone;
public class Assets {
private String assetname;
private String assetamount;
public Assets() {
}
public String getAssetname() {
return assetname;
}
public void setAssetname(String assetname) {
this.assetname = assetname;
}
public String getAssetamount() {
return assetamount;
}
public void setAssetamount(String assetamount) {
this.assetamount = assetamount;
}
}
MyAdapter.java
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private Context context;
private ArrayList<Assets> assets;
MyAdapter(Context c, ArrayList<Assets> a)
{
context = c;
assets = a;
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
return new MyViewHolder(LayoutInflater.from(context).inflate(R.layout.cardview,parent, false));
}
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
holder.name.setText(assets.get(position).getAssetname());
holder.amount.setText(assets.get(position).getAssetamount());
}
@Override
public int getItemCount() {
return assets.size();
}
class MyViewHolder extends RecyclerView.ViewHolder{
TextView name, amount;
public MyViewHolder(@NonNull View itemView) {
super(itemView);
name = itemView.findViewById(R.id.name);
amount = itemView.findViewById(R.id.amount);
}
}
}
这是我要显示数据的位置:overview.java
reference = FirebaseDatabase.getInstance().getReference().child("Assets");
recyclerView = findViewById(R.id.myRecycler);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
reference = FirebaseDatabase.getInstance().getReference().child("Assets");
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
list = new ArrayList<Assets>();
for(DataSnapshot dataSnapshot1: dataSnapshot.getChildren()){
Assets a = dataSnapshot1.getValue(Assets.class);
list.add(a);
}
adapter = new MyAdapter(overview.this,list);
recyclerView.setAdapter(adapter);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Toast.makeText(overview.this, "Something Fishy", Toast.LENGTH_SHORT).show();
}
});
我在以下行的overview.java类中出错:
Assets a = dataSnapshot1.getValue(Assets.class);
[请帮助我,因为当前概述页面上没有任何显示。我假设访问数据库表时出错,但是我不确定。
首先,您有两个字段assetName
和assetAmount
。在Java中,始终使用camelCase
,第一个单词小写,第二个单词以大写字母开头。
由于具有这两个字段,因此还需要在数据库中包含它们,以便能够将对象映射到数据库。因此,保存时需要将结构更改为以下内容:
Assets
randomId
assetName : name
assetAmount : amt
randomId
assetName : name
assetAmount : amt
检索节点Assets
时,请不要使用for循环进行迭代,因为您将检索类型为String
而不是类型为Assets
的值
尝试这样编辑
((Assets) getActivity()).getValue;