JavaFX：根据控件内容显示tooltip

偏执的太偏执、 2023-10-15 09:29 34阅读 0赞

如题。当控件为空，没有内容时显示tooltip，反之不显示。示例如下：

package ch06;
    
    import javafx.application.Application;
    import javafx.application.Platform;
    import javafx.beans.value.ObservableValue;
    import javafx.geometry.VPos;
    import javafx.scene.Node;
    import javafx.scene.Scene;
    import javafx.scene.control.Button;
    import javafx.scene.control.Label;
    import javafx.scene.control.TextField;
    import javafx.scene.layout.GridPane;
    import javafx.scene.paint.Color;
    import javafx.scene.text.Font;
    import javafx.scene.text.Text;
    import javafx.stage.Stage;
    
    /**
     * @copyright 2023-2022
     * @package   ch06
     * @file      MicroHelpApplication.java
     * @date      2023-08-24 08:39
     * @author    qiao wei
     * @version   1.0
     * @brief     
     * @history
     */
    public class MicroHelpApplication extends Application {
    
        public static void main(String[] args) {
            try {
                Application.launch(MicroHelpApplication.class, args);
            } catch (Exception exception) {
                exception.printStackTrace();
            }
        }
        
        public MicroHelpApplication() {}
    
        @Override
        public void start(Stage stage) throws Exception {
            TextField firstNameField = new TextField();
            TextField lastNameField = new TextField();
            TextField salaryField = new TextField();
            
            Button closeButton = new Button("Close");
            closeButton.setOnAction(e -> Platform.exit());
    
            firstNameField.getProperties().put("microHelpText", "Enter the first name");
            lastNameField.getProperties().put("microHelpText", "Enter the last name");
            salaryField.getProperties().put("microHelpText", "Enter a salary greater than $2000.00.");
            
            // The help text node is unmanaged
            helpText.setManaged(false);
            helpText.setTextOrigin(VPos.TOP);
            helpText.setFill(Color.RED);
            helpText.setFont(Font.font(null, 9));
            helpText.setMouseTransparent(true);
            
            // Add all nodes to a GridPane
            GridPane root = new GridPane();
    
            root.add(new Label("First Name:"), 1, 1);
            root.add(firstNameField, 2, 1);
            root.add(new Label("Last Name:"), 1, 2);
            root.add(lastNameField, 2, 2);
            root.add(new Label("Salary:"), 1, 3);
            root.add(salaryField, 2, 3);
            root.add(closeButton, 3, 3);
            root.add(helpText, 4, 3);
            Scene scene = new Scene(root, 300, 100);
            
            // Add a change listener to the scene, so you know when the focus owner
            // changes and display the micro help
            scene.focusOwnerProperty().addListener(
                (ObservableValue<? extends Node> value,
                 Node oldNode,
                 Node newNode) -> focusChanged(value, oldNode, newNode)
            );
            
            stage.setScene(scene);
            stage.setTitle("Showing Micro Help");
            stage.show();
        }
        
        /**
         * @class   MicroHelpApplication
         * @date    2023-08-24 08:58
         * @author  qiao wei
         * @version 1.0
         * @brief   控件获得焦点时触发。
         * @param   
         * @return  
         * @throws
         */
        public void focusChanged(ObservableValue<? extends Node> value,
                                 Node oldNode,
                                 Node newNode) {
            // Focus has changed to a new node
            String microHelpText = (String) newNode.getProperties().get("microHelpText");
            
            if (microHelpText != null && microHelpText.trim().length() > 0) {
                helpText.setText(microHelpText);
                helpText.setVisible(true);
                
                // Position the help text node
                double x = newNode.getLayoutX() +
                    newNode.getLayoutBounds().getMinX() -
                    helpText.getLayoutBounds().getMinX();
                
                double y = newNode.getLayoutY() +
                    newNode.getLayoutBounds().getMinY() +
                    newNode.getLayoutBounds().getHeight() -
                    helpText.getLayoutBounds().getMinX();
                
                helpText.setLayoutX(x);
                helpText.setLayoutY(y);
                helpText.setWrappingWidth(newNode.getLayoutBounds().getWidth());
            }
            else {
                helpText.setVisible(false);
            }
        }
    
        // An instance variable to store the Text node reference
        private Text helpText = new Text();
    }

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[4963c672d73a47869d276719d52036dc.png]: https://img-blog.csdnimg.cn/4963c672d73a47869d276719d52036dc.png