无JSON数组的对象如何在RecyclerView中展示？求技术指导

1. 定义数据实体类 #

先创建一个实体类，用来存储单个货币的价格信息，方便后续RecyclerView适配：

public class CurrencyPrice {
    private String currencyCode; // 存储USD、EUR这类货币代码
    private String min;
    private String max;
    private String current;

    // 构造方法
    public CurrencyPrice(String currencyCode, String min, String max, String current) {
        this.currencyCode = currencyCode;
        this.min = min;
        this.max = max;
        this.current = current;
    }

    // Getter方法，供适配器调用获取数据
    public String getCurrencyCode() { return currencyCode; }
    public String getCurrent() { return current; }
    public String getMin() { return min; }
    public String getMax() { return max; }
}

2. 解析JSON并转换为列表 #

RecyclerView需要的是集合（比如List）而非键值对对象，所以核心是把prices里的键值对转成List<CurrencyPrice>，下面提供两种常用解析方式：

原生JSONObject解析 #

// 假设已获取完整的JSON字符串jsonString
JSONObject rootObj = new JSONObject(jsonString);
JSONObject dataObj = rootObj.getJSONObject("data");
JSONObject pricesObj = dataObj.getJSONObject("prices");

List<CurrencyPrice> priceList = new ArrayList<>();

// 遍历prices对象的所有货币键
Iterator<String> keys = pricesObj.keys();
while (keys.hasNext()) {
    String currencyCode = keys.next();
    JSONObject currencyPriceObj = pricesObj.getJSONObject(currencyCode);
    
    String min = currencyPriceObj.getString("min");
    String max = currencyPriceObj.getString("max");
    String current = currencyPriceObj.getString("current");
    
    priceList.add(new CurrencyPrice(currencyCode, min, max, current));
}

Gson库解析 #

先定义对应整个JSON结构的外层类：

public class PriceResponse {
    private Data data;

    public Data getData() { return data; }

    public static class Data {
        private String message;
        private int status;
        private Map<String, CurrencyDetail> prices;

        public Map<String, CurrencyDetail> getPrices() { return prices; }
    }

    public static class CurrencyDetail {
        private String min;
        private String max;
        private String current;

        // Getter方法
        public String getMin() { return min; }
        public String getMax() { return max; }
        public String getCurrent() { return current; }
    }
}

再解析并转成列表：

Gson gson = new Gson();
PriceResponse response = gson.fromJson(jsonString, PriceResponse.class);
Map<String, PriceResponse.CurrencyDetail> priceMap = response.getData().getPrices();

List<CurrencyPrice> priceList = new ArrayList<>();
for (Map.Entry<String, PriceResponse.CurrencyDetail> entry : priceMap.entrySet()) {
    String currencyCode = entry.getKey();
    PriceResponse.CurrencyDetail detail = entry.getValue();
    
    priceList.add(new CurrencyPrice(currencyCode, detail.getMin(), detail.getMax(), detail.getCurrent()));
}

3. 实现RecyclerView适配器 #

创建适配器，把列表数据绑定到单个条目布局：

public class PriceAdapter extends RecyclerView.Adapter<PriceAdapter.PriceViewHolder> {
    private List<CurrencyPrice> priceList;

    public PriceAdapter(List<CurrencyPrice> priceList) {
        this.priceList = priceList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull PriceViewHolder holder, int position) {
        CurrencyPrice price = priceList.get(position);
        holder.tvCurrency.setText(price.getCurrencyCode());
        holder.tvCurrentPrice.setText(price.getCurrent());
        holder.tvMinPrice.setText("最低: " + price.getMin());
        holder.tvMaxPrice.setText("最高: " + price.getMax());
    }

    @Override
    public int getItemCount() {
        return priceList.size();
    }

    static class PriceViewHolder extends RecyclerView.ViewHolder {
        TextView tvCurrency, tvCurrentPrice, tvMinPrice, tvMaxPrice;

        public PriceViewHolder(@NonNull View itemView) {
            super(itemView);
            tvCurrency = itemView.findViewById(R.id.tv_currency);
            tvCurrentPrice = itemView.findViewById(R.id.tv_current_price);
            tvMinPrice = itemView.findViewById(R.id.tv_min_price);
            tvMaxPrice = itemView.findViewById(R.id.tv_max_price);
        }
    }
}

4. 配置RecyclerView并加载数据 #

在Activity/Fragment中完成RecyclerView的基础配置：

RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
PriceAdapter adapter = new PriceAdapter(priceList);
recyclerView.setAdapter(adapter);

5. 单个条目布局示例 #

创建res/layout/item_currency_price.xml，定义每个货币条目的展示样式：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="16dp"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tv_currency"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:textStyle="bold"/>

    <TextView
        android:id="@+id/tv_current_price"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:layout_marginTop="4dp"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_marginTop="4dp">

        <TextView
            android:id="@+id/tv_min_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="14sp"
            android:textColor="@android:color/darker_gray"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="14sp"
            android:text=" | "
            android:textColor="@android:color/darker_gray"/>

        <TextView
            android:id="@+id/tv_max_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="14sp"
            android:textColor="@android:color/darker_gray"/>
    </LinearLayout>
</LinearLayout>

内容的提问来源于stack exchange，提问作者developerspace null