我想要实现的是能够突出显示
TableView
内文本的某些部分,同时保留使用纯 Label
呈现单元格内容时存在的省略号功能。
所以我追求的是:
我的第一个想法是简单地使用
Label
来实现此目的并传入格式化的 html - 这在 Swing 中是可能的,但(令我惊讶的是)在 JavaFX 中不行,因此无法使用 Label
类来实现这一点。
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,所以考虑到第一个 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如何实现这一目标的解决方案/解决方法。
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 ;
}
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") ;
}
仅使用 CSS 即可正常工作
.table-view .column-header {
-fx-ellipsis-string: "" ;
}
.table-column {
-fx-ellipsis-string: "" ;
}