Question

我打算从TextArea获取选定文本的范围，并更改selectRange的字体颜色。我的TextArea初始化为FXML文件的一部分。我可以通过使用textArea.getSelection（）获得selectRange，我想为上述方法返回的范围内的文本着色。请建议我该怎么做。

Answer 1

首先，我建议您使用任何富文本控件（RichTextFX）。但是，如果您对使用TextArea非常特定，请检查以下方法。

我提供的方法可能不是正确的解决方案，或者可能不适合您的确切要求。但这可以帮助您朝这个方向思考。

这基于Highlighting Strings in JavaFX TextArea中（@en_Knight提供）的想法。我建议先了解此OP，然后检查我的以下实现。

我创建了一个自定义TextArea控件，该控件按照上述OP中提供的相同原理工作。即，混合节点以获得所需的效果。您可以通过更改演示中组合框的值来检查不同的混合效果。我认为您可能需要BlendMode.ADD

在选择文本时，高光仍然保留。

import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.effect.BlendMode;
import javafx.scene.layout.*;
import javafx.scene.shape.Path;
import javafx.scene.shape.PathElement;
import javafx.stage.Stage;

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

public class CustomTextAreaDemo extends Application {
    @Override
    public void start(Stage stage) throws Exception {

        final VBox root = new VBox();
        root.setSpacing(10);
        root.setPadding(new Insets(10));
        final Scene sc = new Scene(root, 600, 300);
        stage.setScene(sc);
        stage.show();

        final CustomTextArea customTextArea = new CustomTextArea();
        customTextArea.setText(
                "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.");
        customTextArea.setWrapText(true);
        customTextArea.setStyle("-fx-font-size: 15px;");
        VBox.setVgrow(customTextArea, Priority.ALWAYS);

        final Button highlight = new Button("Highlight");
        final TextField stF = new TextField("40");
        final TextField enF = new TextField("51");
        final HBox hb = new HBox(highlight, stF, enF);
        hb.setSpacing(10);
        highlight.setOnAction(e -> {
            customTextArea.highlight(Integer.parseInt(stF.getText()), Integer.parseInt(enF.getText()));
        });

        final Button remove = new Button("Remove Highlight");
        remove.setOnAction(e -> customTextArea.removeHighlight());

        final Label lbl = new Label("Resize the window to see if the highlight is in align with text");
        lbl.setStyle("-fx-font-size: 17px;-fx-font-style:italic;");
        final HBox rb = new HBox(remove, lbl);
        rb.setSpacing(10);

        ComboBox<BlendMode> blendModes = new ComboBox<>();
        blendModes.getItems().addAll(BlendMode.values());
        blendModes.getSelectionModel().selectedItemProperty().addListener((obs, old, blend) -> {
            customTextArea.getHighlightPath().setBlendMode(blend);
        });
        blendModes.getSelectionModel().select(BlendMode.ADD);

        root.getChildren().addAll(hb, rb,blendModes, customTextArea);
    }

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

    class CustomTextArea extends TextArea {
        /**
         * Start position of the highlight.
         */
        private int highlightStartPos = -1;

        /**
         * End position of the highlight.
         */
        private int highlightEndPos = -1;

        /**
         * Path node to act as highlight.
         */
        private final Path highlightPath = new Path();

        /**
         * Node to keep reference of the selectionGroup node of the TextArea.
         */
        private Group selectionGroup;

        /**
         * Node to keep reference of the all contents of the TextArea.
         */
        private StackPane contentPane;

        /**
         * Node to keep reference of the content node.
         */
        private Region textContent;

        /**
         * Specifies whether the selection of text is done for purpose of highlighting.
         */
        private boolean highlightInProgress = false;

        public CustomTextArea() {
            highlightPath.setStyle("-fx-fill:red");
            highlightPath.setMouseTransparent(true);
            highlightPath.setManaged(false);
            highlightPath.setStroke(null);
            textProperty().addListener((obs, oldVal, newVal) -> removeHighlight());
            widthProperty().addListener((obs, oldVal, newVal) -> {
                if (highlightStartPos > -1 && highlightEndPos > -1 && selectionGroup != null) {
                    highlightInProgress = true;
                    selectRange(highlightStartPos, highlightEndPos);
                }
            });
        }

        /**
         * Highlights the range of characters in the text area.
         *
         * @param startPos Start position of the character in the text
         * @param endPos   End position of the character in the text
         */
        public void highlight(final int startPos, final int endPos) {
            highlightStartPos = startPos;
            highlightEndPos = endPos;
            highlightInProgress = true;
            selectRange(highlightStartPos, highlightEndPos);
        }

        public Path getHighlightPath() {
            return highlightPath;
        }

        @Override
        protected void layoutChildren() {
            super.layoutChildren();
            if (selectionGroup == null || contentPane == null) {
                final Region content1 = (Region) lookup(".content");
                if (content1 != null) {
                    // Looking for the Group node that is responsible for selection
                    content1
                            .getChildrenUnmodifiable()
                            .stream()
                            .filter(node -> node instanceof Group)
                            .map(node -> (Group) node)
                            .filter(grp -> {
                                final boolean notSelectionGroup =
                                        grp.getChildren().stream().anyMatch(node -> !(node instanceof Path));
                                return !notSelectionGroup;
                            })
                            .findFirst()
                            .ifPresent(n -> {
                                n.boundsInLocalProperty().addListener((obs, old, bil) -> {
                                    if (highlightInProgress) {
                                        updateHightlightBounds();
                                    }
                                });
                                selectionGroup = n;
                            });
                    contentPane = (StackPane) content1.getParent();
                    textContent = content1;
                }
            }
        }

        /**
         * Updates the highlight with the provided bounds.
         */
        private void updateHightlightBounds() {
            if (!selectionGroup.getChildren().isEmpty()) {
                final Path p = (Path) selectionGroup.getChildren().get(0);
                final List<PathElement> elements = new ArrayList<>(p.getElements());

                highlightPath.getElements().clear();
                highlightPath.getElements().addAll(elements);
                final Node textNode = textContent.lookup(".text");
                highlightPath.setLayoutX(textNode.getLayoutX());
                highlightPath.setLayoutY(textNode.getLayoutY());

                if (contentPane != null && !contentPane.getChildren().contains(highlightPath)) {
                    contentPane.getChildren().add(highlightPath);
                }
                highlightInProgress = false;
                Platform.runLater(this::deselect);
            }
        }

        /**
         * Removes the highlight in the text area.
         */
        public void removeHighlight() {
            if (contentPane != null) {
                contentPane.getChildren().remove(highlightPath);
            }
            highlightStartPos = -1;
            highlightEndPos = -1;
        }
    }
}

JavaFX：如何更改TextArea中与selectRange对应的文本的颜色

1 个答案: