JavaFX 的 TableView 具有突出显示文本和省略号功能

Question

我想要实现的是突出显示 TableView 内文本的某些部分，同时保留纯 Label 时存在的省略号功能> 用于呈现单元格内容。

所以我追求的是:

1. 正如您所见，“how”关键字已突出显示。
2. 如果文本太长，省略号会很好地呈现。

我的第一个想法是简单地使用 Label 来实现这一点并传入格式化的 html - 这在 Swing 中是可能的，但(令我惊讶的是)在 JavaFX 中不行，所以没有办法通过标签类。

我的第二次尝试是使用 TextFlow - 但显然，将标签很好地放入列中的省略号功能就这样丢失了(我还发现了一些与此问题无关的其他问题) .

这对我来说是一个非常基本的问题，因此考虑到第一个 JavaFX 版本是 9 年前发布的，我感到相当惊讶。我真的想知道是否有人找到了一些解决方案/解决方法来实现这一目标。

Answer 1

编写一个性能合理的自定义布局并不太难，它的工作方式类似于简化的 HBox 并从左到右放置一些标签。如果您提供 text 属性和 highlightedText 属性，则可以在更改时创建适当的标签。这并不是为了达到生产质量，但应该为您提供一个良好的起点:

import javafx.beans.property.StringProperty;
import javafx.beans.property.StringPropertyBase;
import javafx.css.PseudoClass;
import javafx.scene.Node;
import javafx.scene.control.Label;
import javafx.scene.layout.Pane;

public class HighlightingLabelLayout extends Pane {

    private static final PseudoClass HIGHLIGHTED = PseudoClass.getPseudoClass("highlighted");

    private boolean needsRebuild = true ;

    private final Label ellipsis = new Label("...");

    private final StringProperty text = new StringPropertyBase() {

        @Override
        public String getName() {
            return "text" ;
        }

        @Override
        public Object getBean() {
            return HighlightingLabelLayout.this ;
        }

        @Override
        protected void invalidated() {
            super.invalidated();
            needsRebuild = true ;
            requestLayout();
        }
    };

    private final StringProperty highlightText = new StringPropertyBase() {

        @Override
        public String getName() {
            return "highlightText" ;
        }

        @Override
        public Object getBean() {
            return HighlightingLabelLayout.this ;
        }

        @Override
        protected void invalidated() {
            super.invalidated();
            needsRebuild = true ;
            requestLayout();
        }
    };

    public final StringProperty textProperty() {
        return this.text;
    }


    public final String getText() {
        return this.textProperty().get();
    }


    public final void setText(final String text) {
        this.textProperty().set(text);
    }


    public final StringProperty highlightTextProperty() {
        return this.highlightText;
    }


    public final String getHighlightText() {
        return this.highlightTextProperty().get();
    }


    public final void setHighlightText(final String highlightText) {
        this.highlightTextProperty().set(highlightText);
    }

    public HighlightingLabelLayout() {
        ellipsis.getStyleClass().add("ellipsis");
        getStylesheets().add(getClass().getResource("highlighting-label-layout.css").toExternalForm());
    }

    @Override
    protected void layoutChildren() {
        if (needsRebuild) {
            rebuild() ;
        }
        double width = getWidth();
        double x = snappedLeftInset() ;
        double y = snappedTopInset() ;
        boolean truncated = false ;
        for (Node label : getChildren()) {
            double labelWidth = label.prefWidth(-1);
            double labelHeight = label.prefHeight(labelWidth);
            if (label == ellipsis) {
                label.resizeRelocate(width - labelWidth - snappedRightInset(), y, labelWidth, labelHeight);
                continue ;
            }
            if (truncated) {
                label.setVisible(false);
                continue ;
            }
            if (labelWidth + x > width - snappedLeftInset() - snappedRightInset()) {
                label.resizeRelocate(x, y, width - snappedLeftInset() - snappedRightInset() - x, labelHeight);
                truncated = true ;
                label.setVisible(true);
                x = width - snappedRightInset();
                continue ;
            }
            label.resizeRelocate(x, y, labelWidth, labelHeight);
            x+=labelWidth ;
        }
        ellipsis.setVisible(truncated);
    }

    @Override
    protected double computePrefWidth(double height) {
        if (needsRebuild) {
            rebuild();
        }
        double width = 0 ;
        for (Node label : getChildren()) {
            if (label != ellipsis) {
                width += label.prefWidth(height);
            }
        }
        return width ;
    }

    @Override
    protected double computeMaxWidth(double height) {
        return computePrefWidth(height);
    }

    @Override
    protected double computeMinWidth(double height) {
        return Math.min(ellipsis.minWidth(height), computePrefWidth(height));
    }

    @Override
    protected double computePrefHeight(double width) {
        if (needsRebuild) {
            rebuild();
        }
        double height = 0 ;
        for (Node label : getChildren()) {
            if (label != ellipsis) {
                double labelWidth = label.prefWidth(-1);
                double labelHeight = label.prefHeight(labelWidth);
                if (labelHeight > height) {
                    height = labelHeight ;
                }
            }
        }
        return height ;
    }

    @Override
    protected double computeMinHeight(double width) {
        return Math.min(computePrefHeight(width), ellipsis.prefHeight(ellipsis.prefWidth(-1)));
    }

    @Override
    protected double computeMaxHeight(double width) {
        return computePrefHeight(width);
    }

    // Performance could probably be improved by caching and reusing the labels...
    private void rebuild() {
        String[] words = text.get().split("\\s");
        String highlight = highlightText.get();
        getChildren().clear();
        StringBuffer buffer = new StringBuffer();
        boolean addLeadingSpace = false ;
        for (int i = 0 ; i < words.length ; i++) {
            if (words[i].equals(highlight)) {
                if ( i > 0) {
                    getChildren().add(new Label(buffer.toString()));
                    buffer.setLength(0);
                }
                Label label = new Label(words[i]);
                label.pseudoClassStateChanged(HIGHLIGHTED, true);
                addLeadingSpace = true ;
                getChildren().add(label);
            } else {
                if (addLeadingSpace) {
                    buffer.append(' ');
                }
                buffer.append(words[i]);
                if (i < words.length - 1) {
                    buffer.append(' ');
                }
                addLeadingSpace = false ;
            }
        }
        if (buffer.length() > 0) {
            getChildren().add(new Label(buffer.toString()));
        }
        getChildren().add(ellipsis);

        needsRebuild = false ;
    }

}

以及对应的CSS文件

.label {
    -highlight-color: yellow ;
    -fx-background-color: -fx-background ;
    -fx-ellipsis-string: "" ;
}
.label:highlighted {
    -fx-background: -highlight-color ;
}

正如评论所述，如果需要，可以利用一些性能改进。

这是一个快速测试，在表格单元格中使用它:

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.scene.Scene;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class HighlightingLabelLayoutTest extends Application {

    @Override
    public void start(Stage primaryStage) {

        TextField searchField = new TextField();

        TableView<Item> table = new TableView<>();
        TableColumn<Item, String> itemCol = new TableColumn<>("Item");
        itemCol.setCellValueFactory(cellData -> cellData.getValue().nameProperty());
        table.getColumns().add(itemCol);

        TableColumn<Item, String> dataCol = new TableColumn<>("Data");
        dataCol.setCellValueFactory(cellData -> cellData.getValue().dataProperty());
        dataCol.setPrefWidth(200);
        table.getColumns().add(dataCol);

        dataCol.setCellFactory(col -> new TableCell<Item, String>() {
            private final HighlightingLabelLayout layout = new HighlightingLabelLayout();

            {
                layout.highlightTextProperty().bind(searchField.textProperty());
            }

            @Override
            protected void updateItem(String data, boolean empty) {
                super.updateItem(data, empty);
                if (empty) {
                    setGraphic(null);
                } else {
                    layout.setText(data);
                    setGraphic(layout);
                }
            }
        });

        table.getItems().setAll(generateData(200, 10));



        VBox root = new VBox(5, searchField, table);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }

    private List<Item> generateData(int numItems, int wordsPerItem) {
        List<Item> items = new ArrayList<>();
        Random rng = new Random();
        for (int i = 1 ; i <= numItems ; i++) {
            String name = "Item "+i;
            List<String> words = new ArrayList<>();
            for (int j = 0 ; j < wordsPerItem ; j++) {
                words.add(WORDS[rng.nextInt(WORDS.length)].toLowerCase());
            }
            String data = String.join(" ", words);
            items.add(new Item(name, data));
        }
        return items ;
    }

    public static class Item {
        private final StringProperty name = new SimpleStringProperty();
        private final StringProperty data = new SimpleStringProperty();

        public Item(String name, String data) {
            setName(name);
            setData(data);
        }

        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);
        }


        public final StringProperty dataProperty() {
            return this.data;
        }


        public final String getData() {
            return this.dataProperty().get();
        }


        public final void setData(final String data) {
            this.dataProperty().set(data);
        }



    }

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

    private static final String[] WORDS = ("Lorem ipsum dolor sit amet, "
            + "consectetur adipiscing elit. Sed pulvinar massa at arcu ultrices, "
            + "nec elementum velit vestibulum. Integer eget elit justo. "
            + "Orci varius natoque penatibus et magnis dis parturient montes, "
            + "nascetur ridiculus mus. Duis ultricies diam turpis, eget accumsan risus convallis a. "
            + "Pellentesque rhoncus viverra sem, sed consequat lorem.").split("\\W") ;
}