java - 如何使用两个数据模型在 RecyclerView 中创建多个 View 类型？

Question

我有使用 Retrofit 库从 API 获取的数据。 API 完美运行。问题是如何将数据放入列表并使用 RecyclerView 适配器显示它。我尝试使用 HashMap 但它会使应用程序崩溃。有人可以帮我展示这个问题的正确结构和解决方案吗？

来自API的数据

报表模型

在报表列表中记录模型

我已经从API得到的数据

我要显示的界面

Answer 1

我建议您展平模型。而不是让 parent 带着 child ，只有一个层次。此外，为您的 UI 和 Retrofit 使用不同的数据模型。需要时，在模型之间进行转换。这样，事情就不会紧密耦合，你可以在转换时做其他事情，例如如果需要格式化字符串。

// This is what the data model will extend
interface UiBaseModel { }

// monthly detail report
class UiMonthlyDetailReport implements UiBaseModel {

    private String month;
    private String total;

    UiMonthlyDetailReport(String month, String total) {
        this.month = month;
        this.total = total;
    }

    public String getMonth() {
        return month;
    }

    public String getTotal() {
        return total;
    }
}

// monthly detail record
class UiMonthlyDetailsRecord implements UiBaseModel {

    private String month;
    private String expenseName;
    private String expenseIcon;
    private String expenseTotal;

    UiMonthlyDetailsRecord(String month, String expenseName, String expenseIcon, String expenseTotal) {
        this.month = month;
        this.expenseName = expenseName;
        this.expenseIcon = expenseIcon;
        this.expenseTotal = expenseTotal;
    }

    public String getMonth() {
        return month;
    }

    public String getExpenseName() {
        return expenseName;
    }

    public String getExpenseIcon() {
        return expenseIcon;
    }

    public String getExpenseTotal() {
        return expenseTotal;
    }
}



// In your activity / fragment / viewmodel / presenter:

    List<ReportMonthlyDetailsReport> reports = ... // get your data from retrofit
    List<UiBaseModel> uiModels = ArrayList<UiBaseModel>();
    for (ReportMonthlyDetailsReport report : reports) {
        // First records, then report
        List<ReportMonthlyDetailsRecord> records = report.getRecords();
        for (ReportMonthlyDetailsRecord record : records) {
            // Create UI model and add to list
            UiMonthlyDetailsRecord uiRecord = UiMonthlyDetailsRecord(record.getMonth_label(), record.getExpense_type_name(), record.getExpense_type_icon(), record.getExpense_type_total());
            uiModels.add(uiRecord);
        }
        // Lastly, add the report
        UiMonthlyDetailsReport uiReport = UiMonthlyDetailsReport(report.getMonth_label(), report.getMonthly_total());
        uiModels.add(uiReport);
    }

    // Use the ui models (for the recycler adapter)
    MonthlyDetailsAdapter adapter = MonthlyDetailsAdapter(uiModels);
    recyclerView.adapter = adapter;

剩下要做的就是适配器。有很多关于如何支持多种 View 类型的例子，简单的未完成的例子:

public class MonthlyDetailsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private final static int VIEW_TYPE_RECORD = 0;
    private final static int VIEW_TYPE_REPORT = 1;

    private List<UiBaseModel> data;

    MonthlyDetailsAdapter(List<UiBaseModel> data) {
        this.data = data;
    }

    class RecordViewHolder extends RecyclerView.ViewHolder {
        public RecordViewHolder(@NonNull View itemView) {
            // code
            super(itemView);
        }
    }

    class ReportViewHolder extends RecyclerView.ViewHolder {
        public ReportViewHolder(@NonNull View itemView) {
            // code
            super(itemView);
        }
    }

    @Override
    public int getItemViewType(int position) {
        UiBaseModel item = data.get(position);
        if (item instanceof UiMonthlyDetailsRecord) {
            return VIEW_TYPE_RECORD;
        } else {
            return VIEW_TYPE_REPORT;
        }
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        if (holder instanceof RecordViewHolder) {
            UiMonthlyDetailsRecord record = (UiMonthlyDetailsRecord) data.get(position);
            // bind record
        } else if (holder instanceof ReportViewHolder) {
            UiMonthlyDetailsReport report = (UiMonthlyDetailsReport) data.get(position);
            // bind report
        }
    }
}