我的自定义列表视图中的另一个列表与 Firebase

Question

我正在尝试在我的自定义列表视图中显示另一个列表，如下图所示。我已成功显示前三个孩子（姓名、运动和城镇）。但是当我添加覆盖子时，我在主要活动中收到此错误“无法将类型数组列表的值转换为字符串”。

错误信息

Failed to convert value of type java.util.ArrayList to String

这是我试图实现的显示 This is what im trying to achieve

这是我的 firebase 数据库结构 db structure

我的主要活动的代码如下

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mListView = (ListView)findViewById(R.id.cusListView);
    mTextView = (TextView)findViewById(R.id.textV);

    mRef = FirebaseDatabase.getInstance().getReference().child("Person");
        mRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                showData(dataSnapshot);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

}

private void showData(DataSnapshot dataSnapshot){

    ArrayList<PeopleGetSet> array = new ArrayList<>();

    for(DataSnapshot ds : dataSnapshot.getChildren()) {
        PeopleGetSet arr = ds.getValue(PeopleGetSet.class);

        array.add(arr);

        ViewDatabase adapter = new ViewDatabase(this, R.layout.adapter_view_layout, array);
        mListView.setAdapter(adapter);

    }

}

这是我的适配器代码

public class ViewDatabase extends ArrayAdapter<PeopleGetSet> {
private static final String TAG="ViewDatabase";
private Context mContext;
int mResource;

public ViewDatabase(@NonNull Context context, int resource, @NonNull List<PeopleGetSet> objects) {
    super(context, resource, objects);
    this.mContext=context;
    mResource = resource;
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    String name =getItem(position).getName();
    String sport =getItem(position).getSport();
    String town =getItem(position).getTown();
    String Coverage =getItem(position).getCoverage();
    PeopleGetSet person = new PeopleGetSet(name,sport, town, Coverage);

    LayoutInflater inflater = LayoutInflater.from(mContext);
    convertView=inflater.inflate(mResource, parent, false);

    TextView tvName = (TextView)convertView.findViewById(R.id.textView);
    TextView tvSport = (TextView)convertView.findViewById(R.id.textView2);
    TextView tvTown = (TextView)convertView.findViewById(R.id.textView3);
    TextView tvCoverage = (TextView)convertView.findViewById(R.id.textView4);

    tvName.setText(name);
    tvSport.setText(sport);
    tvTown.setText(town);
    tvCoverage.setText(Coverage);
    return convertView;
   }

}

这是我的 Getter 和 setter 代码

public class PeopleGetSet {
private String name;
private String sport;
private String town;
private String Coverage;

public PeopleGetSet() {

}

public PeopleGetSet(String name, String sport, String town, String Coverage) {
    this.name = name;
    this.sport = sport;
    this.town = town;
    this.Coverage = Coverage;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getSport() {
    return sport;
}

public void setSport(String sport) {
    this.sport = sport;
}

public String getTown() {
    return town;
}

public void setTown(String town) {
    this.town = town;
}

public String getCoverage() {
    return Coverage;
}

public void setCoverage(String coverage) {
    Coverage = coverage;
   }
}

Answer 1

我的意思是这样的：

public class PeopleGetSet {
   private String name;
   private String sport;
   private String town;
   private Coverage coverage; 
    ... default code
}

public class Coverage {
   private ArrayList<String> names;
   ... default code
}

Answer 2

问题出在您的 Getter Setter 类中 将 Coverage 添加为您的 PeopleGetSet 类中的 Hashmap。 Coverage 不是其数组的字符串，因此要从 firebase 读取数组，您应该使用 HashMap

      public class PeopleGetSet {
      private String name;
      private String sport;
      private String town;
      private HashMap<String,String> Coverage ;

      public PeopleGetSet() {

       }

     public PeopleGetSet(String name, String sport, String town,  HashMap<String, String> Coverage) {
      this.name = name;
      this.sport = sport;
      this.town = town;
     this.Coverage = Coverage;
     }

    public String getName() {
    return name;
    }

   public void setName(String name) {
    this.name = name;
    }

    public String getSport() {
      return sport;
    }

   public void setSport(String sport) {
    this.sport = sport;
   }

    public String getTown() {
       return town;
     }

public  HashMap<String,String> getCoverage() {
       return Coverage;
     }

Answer 3

有一种简单的方法可以在一个 ListView 中扩展多个视图。这是我的示例代码。

public class MyExampleCode extends ArrayAdapter<Object> {

private static final int TYPE_1 = 0;
private static final int TYPE_2 = 1;

private Context context;
private List<Object> objectList;

public MyExampleCode(Context context, List<Object> objectList) {
    super(context,layout,objectList);

    this.context = context;
    this.objectList = objectList;
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

    if (getItemViewType(position) == TYPE_1) {

        PeopleGetSet peopleGetSet = (PeopleGetSet)objectList.get(position);
        //handle code for first object, inflate layout and fill it
    } else {

        Coverage coverage = (Coverage)objectList.get(position);
        //handle code for second object, inflate layout and fill it
    }
}

@Override
public int getItemViewType(int position) {

    if (getItem(position) instanceof PeopleGetSet) {

        return TYPE_1;
    } else {

        return TYPE_2;
    }
}

@Nullable
@Override
public Object getItem(int position) {

    return objectList.get(position);
}

@Override
public int getCount() {

    return objectList.size();
}

}

@编辑
让我们更新您的代码

private void showData(DataSnapshot dataSnapshot){

    List<Object> array = new ArrayList<>();

    for(DataSnapshot ds : dataSnapshot.getChildren()) {
        PeopleGetSet arr = ds.getValue(PeopleGetSet.class);
        Coverage arr2 = arr.getCoverage();

        array.add(arr);
        array.add(arr2);
    }
    ViewDatabase adapter = new ViewDatabase(this, array);
    mListView.setAdapter(adapter);
}