Question

我正在根据评论修改我的问题。我有一个JavaFX TableView，其复选框列的数量仅在运行时已知。因此，要创建列，我会这样做：

dispatch_async(transitionQueue,^{
     //heavy lifting code
viewerPVC=..... //this should block here otherwise will not work
  dispatch_async(dispatch_get_main_queue(), ^{
      [activity stopAnimating];
      [self transitionToAnotherViewer:viewerPVC];
  });
});

问题是，这个TableView的表模型怎么样？如果有一个固定数量的复选框列，比如2列，我的模型如下所示：

    TableColumn attributeColumn = new TableColumn("Attribut");
    attributeColumn.setCellValueFactory(new PropertyValueFactory<AttributeRow, String>("name"));        
    attributeTable.getColumns().add(attributeColumn);

    for (String group : companyGroups)
    {
        TableColumn< AttributeRow, Boolean > groupColumn = new TableColumn<>( group );
        groupColumn.setCellFactory(CheckBoxTableCell.forTableColumn(groupColumn)); 
        groupColumn.setCellValueFactory( f -> f.getValue().activeProperty());
        groupColumn.setEditable(true);
        attributeTable.getColumns().add(groupColumn);
    }

如果我有一个字符串列和一个复选框列，则此模型有效。但是我该怎么做，如果我有多个复选框列，其数字只在运行时知道？

Answer 1

您还没有真正描述过数据的结构，但看起来有一些String s（companyGroups）的集合，每一行都是由表格表示的一个String（name）和一个布尔值，用于companyGroups的每个元素。因此，实现此目的的一种方法就是在模型类Map<String, BooleanProperty>中定义AttributeRow，其中地图中的键旨在成为companyGroups的元素：

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;

public class AttributeRow {

    private final StringProperty name = new SimpleStringProperty();

    private final Map<String, BooleanProperty> activeByGroup = new HashMap<>();

    public AttributeRow(List<String> companyGroups) {
        for (String group : companyGroups) {
            activeByGroup.put(group, new SimpleBooleanProperty()) ;
        }
    }

    public final BooleanProperty activeProperty(String group) {
        // might need to deal with the case where
        // there is no entry in the map for group
        // (else calls to isActive(...) and setActive(...) with 
        // a non-existent group will give a null pointer exception):

        return activeByGroup.get(group) ;
    }

    public final boolean isActive(String group) {
        return activeProperty(group).get();
    }

    public final void setActive(String group, boolean active) {
        activeProperty(group).set(active);
    }

    public final StringProperty nameProperty() {
        return this.name;
    }


    public final String getName() {
        return this.nameProperty().get();
    }


    public final void setName(final String name) {
        this.nameProperty().set(name);
    }



}

列的单元格值工厂没有什么特别之处 - 它仍然只需将每一行映射到该列的相应observable属性：

for (String group : groups) {
    TableColumn<AttributeRow, Boolean> groupColumn = new TableColumn<>(group);
    groupColumn.setCellFactory(CheckBoxTableCell.forTableColumn(groupColumn));
    groupColumn.setCellValueFactory(cellData -> cellData.getValue().activeProperty(group));
    attributeTable.getColumns().add(groupColumn);
}

当然要更新值，只需更新模型：

Button selectAll = new Button("Select all");
selectAll.setOnAction(e -> {
    for (AttributeRow row : attributeTable.getItems()) {
        for (String group : groups) {
            row.setActive(group, true);
        }
    }
});

这是一个SSCCE：

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.CheckBoxTableCell;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class TableWithMappedBooleans extends Application {

    private static final List<String> groups = Arrays.asList("Group 1", "Group 2", "Group 3", "Group 4");

    @Override
    public void start(Stage primaryStage) {

        TableView<AttributeRow> attributeTable = new TableView<>();
        attributeTable.setEditable(true);

        TableColumn<AttributeRow, String> attributeColumn = new TableColumn<>("Attribute");
        attributeColumn.setCellValueFactory(cellData -> cellData.getValue().nameProperty());

        attributeTable.getColumns().add(attributeColumn);

        for (String group : groups) {
            TableColumn<AttributeRow, Boolean> groupColumn = new TableColumn<>(group);
            groupColumn.setCellFactory(CheckBoxTableCell.forTableColumn(groupColumn));
            groupColumn.setCellValueFactory(cellData -> cellData.getValue().activeProperty(group));
            attributeTable.getColumns().add(groupColumn);
        }

        // generate data:
        for (int i = 1 ; i <= 10; i++) {
            AttributeRow row = new AttributeRow(groups);
            row.setName("Attribute "+i);
            attributeTable.getItems().add(row);
        }

        // button to select everything:

        Button selectAll = new Button("Select all");
        selectAll.setOnAction(e -> {
            for (AttributeRow row : attributeTable.getItems()) {
                for (String group : groups) {
                    row.setActive(group, true);
                }
            }
        });

        // for debugging, to check data are updated from check boxes:
        Button dumpDataButton = new Button("Dump data");
        dumpDataButton.setOnAction(e -> {
            for (AttributeRow row : attributeTable.getItems()) {
                String groupList = groups.stream()
                        .filter(group -> row.isActive(group))
                        .collect(Collectors.joining(", "));
                System.out.println(row.getName() + " : " + groupList);
            }
            System.out.println();
        });

        HBox buttons = new HBox(5, selectAll, dumpDataButton);
        buttons.setAlignment(Pos.CENTER);
        buttons.setPadding(new Insets(5));

        BorderPane root = new BorderPane(attributeTable, null, null, buttons, null);

        Scene scene = new Scene(root);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

编辑：具有动态列号的TableView模型

1 个答案: