使用Comparator进行Java FX表列排序不起作用 [英] Java FX table column sorting with Comparator does not work

问题描述

在Java FX中，我想在已排序的TableView中显示此模型：

In Java FX I would like to display this Model in a sorted TableView:

   public class ProfilZuordnungTableRowModel {
    private int id;
    private double kundenwert;
    private String kundenwertFormatted;
    private BooleanProperty selected; }

我想将表列排序与列集成 Kundenwert。
显示的值应该是属性kundenwertFormatted（String），并且应该使用属性kundenwert（Double）进行排序。

I would like to integrate a table column sorting with the column "Kundenwert". The displayed value should be the attribute "kundenwertFormatted" (String) and for sorting the attribute "kundenwert" (Double) should be used.

所以我写了比较器：

class ProfilZuordnungTableRowModelComparator implements Comparator<ProfilZuordnungTableRowModel> {

    @Override
    public int compare(ProfilZuordnungTableRowModel t, ProfilZuordnungTableRowModel t1) {
         return t.getKundenwert() < t1.getKundenwert() ? -1 : t.getKundenwert() == t1.getKundenwert() ? 0 : 1;
    }
}

据我所知，这个比较器应该用于以下方式：

In my understanding this comparator should be used in the following way:

    TableColumn kundenwertColumn = new TableColumn();
    kundenwertColumn.setText("Kundenwert");

    kundenwertColumn.setCellValueFactory(new PropertyValueFactory("kundenwertFormatted"));
    kundenwertColumn.setComparator(new ProfilZuordnungTableRowModelComparator());

但是当尝试按Kundenwert列排序时，我得到以下异常：

But when trying to sort by the column "Kundenwert" I get the following exception:

java.lang.ClassCastException: java.lang.String cannot be cast to model.ProfilZuordnungTableRowModel
    at dialog.TableCellFactorySample$ProfilZuordnungTableRowModelComparator.compare(TableCellFactorySample.java:53)

指向此行：

kundenwertColumn.setComparator(new ProfilZuordnungTableRowModelComparator());

任何想法？

推荐答案

对于显示 Kundenwert 的列，使用 CellFactory 可以解决您的问题。这样，您不需要模型中的 kundenwertFormatted 字段，因为格式化将由单元格工厂完成：

Your problem can be solved by using a CellFactory for the column displaying Kundenwert. This way you don't need the kundenwertFormatted field in your model, since formatting will be done by the cell factory:

public class KundenwertCellFactory implements Callback<TableColumn<ProfilZuordnungTableRowModel, Double>, TableCell<ProfilZuordnungTableRowModel, Double>> {

    public TableCell<ProfilZuordnungTableRowModel, Double> call(TableColumn<ProfilZuordnungTableRowModel, Double> param) {
        TableCell<ProfilZuordnungTableRowModel, Double> cell = new TableCell<ProfilZuordnungTableRowModel, Double>() {

            @Override
            public void updateItem(final Double item, boolean empty) {
                if (item != null) {
                    setText(item.toString()); // you can format your value here
                }
            }
        };
        return cell;
    }
}

然后，您可以创建比较器来比较 kundenwert 这是双倍的：

Then, you can create your comparator to compare kundenwert which is double:

public class KundenwerComparator implements Comparator<Double> {

    public int compare(Double o1, Double o2) {
        return o1 < o2 ? -1 : o1 == o2 ? 0 : 1;

    }

}

最后，你可以按如下方式设置列：

Finally, you can setup your column as follows:

TableColumn<ProfilZuordnungTableRowModel, Double> kundenwertColumn = new TableColumn<ProfilZuordnungTableRowModel, Double>();
kundenwertColumn.setText("Kundenwert");

kundenwertColumn.setCellValueFactory(new PropertyValueFactory<ProfilZuordnungTableRowModel, Double>("kundenwert"));
kundenwertColumn.setComparator(new KundenwerComparator());
kundenwertColumn.setCellFactory(new KundenwertCellFactory());

请注意，我使用了类型参数，因为 TableColumn （和它的同伴）是通用的。

Note that I used type arguments since TableColumn (and it's companions) is generic.

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