在 Vaadin Grid 中添加子标题行/汇总行

Question

是否可以在 Vaadin 网格中添加汇总行？

我目前有一个网格，它有一个标题行来连接列并在顶部提供一个很好的概览。但是，我想在整个网格中添加类似的标题以标记一个部分的结尾。似乎只能在标题部分添加标题，这只会填满网格的头部。页脚在底部执行相同的操作。

但是，如果我想在网格中添加一个特殊的行而不需要创建一个新的网格组件呢？一种是可见的数据分隔符。

Answer 1

根据您的需求和您的应用程序的复杂程度，您可以fake 一些（可能很小的）努力。您可以在下面找到一个可以帮助您入门的简单示例。

1) 与BeanItemContainer 一起使用的通用类来显示两个类别的行

public abstract class Row {
    private String name;
    private int amount;

    public Row(String name, int amount) {
        this.name = name;
        this.amount = amount;
    }

    public String getName() {
        return name;
    }

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

    public int getAmount() {
        return amount;
    }

    public void setAmount(int amount) {
        this.amount = amount;
    }

    // provide a custom style/type for the current row
    public abstract String getRowType();
}

2) 常规产品行

public class ProductRow extends Row {
    public ProductRow(String name, int amount) {
        super(name, amount);
    }

    @Override
    public String getRowType() {
        return "product-row";
    }
}

3) 特殊行显示上一批产品的总数

public class TotalRow extends Row {
    public TotalRow(int sum) {
        super("Total", sum);
    }

    @Override
    public String getRowType() {
        return "total-row";
    }
}

4) 网格本身

public class GridWithIntermediateRowsComponent extends VerticalLayout {
    private static final String[] AVAILABLE_PRODUCTS = new String[]{"Banana", "Apple", "Coconut", "Pineapple", "Melon"};
    private Random random = new Random();

    public GridWithIntermediateRowsComponent() {
        BeanItemContainer<Row> container = new BeanItemContainer<>(Row.class);
        Grid grid = new Grid(container);

        // show only the relevant columns, the style one is used only to change the background
        grid.setColumns("name", "amount");

        // set a style generator so we can draw the "total" rows differently
        grid.setCellStyleGenerator(row -> ((Row) row.getItemId()).getRowType());

        // create some dummy data to display
        for (int i = 0; i < random.nextInt(10) + 1; i++) {
            container.addAll(createItemBatch(random.nextInt(5) + 1));
        }

        addComponent(grid);
    }

    private List<Row> createItemBatch(int total) {
        List<Row> rows = new ArrayList<>(total + 1);

        // add a batch of products
        String product = AVAILABLE_PRODUCTS[random.nextInt(AVAILABLE_PRODUCTS.length)];
        for (int i = 0; i < total; i++) {
            rows.add(new ProductRow(product, random.nextInt(100) + 1));
        }

        // calculate and add a "total row"
        rows.add(calculateTotal(rows));

        return rows;
    }

    private Row calculateTotal(List<Row> rows) {
        return new TotalRow(rows.stream().mapToInt(Row::getAmount).sum());
    }
}

5) 主题风格

@mixin mytheme {
  @include valo;
  // Insert your own theme rules here

  .v-grid-row > td.total-row {
    background-color: #c4e7b7;
    font-weight: bold;
  }
}

6) 结果