Javafx Tableview在当前视图中保留选定的行

Question

我正在使用javafx tableview进行主动排序并每毫秒插入一个新行...

我想要这个功能:

如果我选择了一行,那么当插入新行时,它应该保持可见(不应该从我表的当前可见部分向上或向下).

Answer 1

这可能是它周围的很长时间,它有点hackish,但当我需要做类似的事情时,它对我有用.

答案的要点是你需要访问该VirtualFlow成员TableViewSkin.这并不像声音那么简单,因为在解析CSS之前不会加载外观.我添加了一个Listener到skinProperty的TableView,并能得到VirtualFlow这样的.

tableView.skinProperty().addListener(new ChangeListener<Skin>()
{
   @Override
   public void changed(ObservableValue<? extends Skin> ov, Skin t, Skin t1)
   {
      if (t1 == null) { return; }

      TableViewSkin tvs = (TableViewSkin)t1;
      ObservableList<Node> kids = tvs.getChildrenUnmodifiable();

      if (kids == null || kids.isEmpty()) { return; }
      flow = (VirtualFlow)kids.get(1);
   }
});

获得后VirtualFlow,您可以收听表格的ObservableList更改并检查以确保所选项目仍在视口中.

countries.addListener(new ListChangeListener<Country>()
{
   @Override
   public void onChanged(ListChangeListener.Change<? extends Country> change)
   {
      while (change.next())
      {
          if (change.wasAdded())
          {
             if (flow == null) { return; }
             int first = flow.getFirstVisibleCell().getIndex();
             int last = flow.getLastVisibleCell().getIndex();
             int selected = tableView.getSelectionModel().getSelectedIndex();

             if (selected < first || selected > last)
             {
                flow.show(selected);
             }
          }
       }
   }
});

There will still be a bit of bookkeeping to manage. For instance, if you wanted to place focus back on the table. Also, it's worth noting that the VirtualFlow isn't strictly bound by the visible rectangle of the table, so an item may be considered visible even if it is just outside the viewport. You can study the VirtualFlow for more details.

Here's a SSCCE.

JavaFXApplication21.java:

package javafxapplication21;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class JavaFXApplication21 extends Application
{
    @Override
    public void start(Stage stage) throws Exception
    {
        Parent root = FXMLLoader.load(getClass().getResource("Sample.fxml"));

        Scene scene = new Scene(root);

        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args)
    {
        launch(args);
    }
}

Sample.fxml:

<?xml version="1.0" encoding="UTF-8"?>

<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane id="AnchorPane" prefHeight="200.0" prefWidth="200.0" xmlns:fx="http://javafx.com/fxml" fx:controller="javafxapplication21.SampleController">
  <children>
    <ToolBar AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
      <items>
        <Button fx:id="insertBtn" mnemonicParsing="false" text="Insert" />
      </items>
    </ToolBar>
    <TableView fx:id="tableView" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="31.0">
      <columns>
        <TableColumn prefWidth="100.0" text="Country" fx:id="countryColumn" />
        <TableColumn prefWidth="100.0" text="Capital" fx:id="capitalColumn" />
      </columns>
    </TableView>
  </children>
</AnchorPane>

SampleController.java:

package javafxapplication21;

import com.sun.javafx.scene.control.skin.TableViewSkin;
import com.sun.javafx.scene.control.skin.VirtualFlow;
import java.net.URL;
import java.util.*;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.collections.*;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.control.*;
import javafx.scene.control.cell.PropertyValueFactory;

public class SampleController implements Initializable
{
    @FXML private Button insertBtn;
    @FXML private TableView<Country> tableView;
    @FXML private TableColumn<Country, String> countryColumn;
    @FXML private TableColumn<Country, String> capitalColumn;

    private VirtualFlow flow;

    private ObservableList<Country> countries =
            FXCollections.observableArrayList();
    private List<Country> insertList = new ArrayList<>();

    public SampleController()
    {
        countries.addAll(new Country("AG", "Buenos Aires"),
                new Country("AU", "Vienna"),
                new Country("BY", "Minsk"),
                new Country("CO", "Bogota"),
                new Country("EG", "Cairo"));

        insertList.add(new Country("ZI", "Harare"));
        insertList.add(new Country("UK", "London"));
        insertList.add(new Country("TW", "Taipei"));
    }

    @Override
    public void initialize(URL url, ResourceBundle rb)
    {
        countryColumn.setCellValueFactory(
                new PropertyValueFactory<Country, String>("name"));
        capitalColumn.setCellValueFactory(
                new PropertyValueFactory<Country, String>("capital"));

        tableView.setItems(countries);

        tableView.skinProperty().addListener(new ChangeListener<Skin>()
        {
            @Override
            public void changed(ObservableValue<? extends Skin> ov,
                Skin t, Skin t1)
            {
                if (t1 == null) { return; }

                TableViewSkin tvs = (TableViewSkin)t1;
                ObservableList<Node> kids = tvs.getChildrenUnmodifiable();

                if (kids == null || kids.isEmpty()) { return; }

                flow = (VirtualFlow)kids.get(1);
            }
        });

        insertBtn.setOnAction(new EventHandler<ActionEvent>()
        {
            @Override
            public void handle(ActionEvent t)
            {
                if (!insertList.isEmpty())
                {
                    countries.add(2, insertList.get(0));
                    insertList.remove(0);
                }
            }
        });

        countries.addListener(new ListChangeListener<Country>()
        {
            @Override
            public void onChanged(ListChangeListener.Change<? extends Country> change)
            {
                while (change.next())
                {
                    if (change.wasAdded())
                    {
                        if (flow == null) { return; }
                        int first = flow.getFirstVisibleCell().getIndex();
                        int last = flow.getLastVisibleCell().getIndex();
                        int selected = tableView.getSelectionModel().getSelectedIndex();

                        if (selected < first || selected > last)
                        {
                            flow.show(selected);
                        }
                    }
                }
            }
        });
    }

    public class Country
    {
        private SimpleStringProperty name;
        private SimpleStringProperty capital;

        public Country(String name, String capital)
        {
            this.name = new SimpleStringProperty(name);
            this.capital = new SimpleStringProperty(capital);
        }

        public SimpleStringProperty nameProperty() { return name; }
        public SimpleStringProperty capitalProperty() { return capital; }
    }
}