accordion - 防止 JavaFX 中的手风琴折叠

Question

有没有一种简单的方法可以防止 JavaFX 2.1 中的手风琴完全崩溃？我有一个带有几个条目的手风琴，但是如果用户单击活动的手风琴条目，它会折叠手风琴。

我可能可以使用鼠标单击侦听器来检查是否进行检查并采取相应的行动，但这感觉应该比完成更简单。

Answer 1

向当前展开的手风琴窗格添加一个侦听器，并通过修改它的 collapsible 属性来防止它被用户折叠。

这是一个示例应用程序：

import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.value.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class AccordionSample extends Application {
  public static void main(String[] args) { launch(args); }
  @Override public void start(Stage primaryStage) {
    // create some titled panes to go in an accordion.
    TitledPane adminPane = new TitledPane("Animals", 
      VBoxBuilder.create().style("-fx-padding: 10").spacing(10).children(
        ButtonBuilder.create().text("Zebra").maxWidth(Double.MAX_VALUE).build(),
        ButtonBuilder.create().text("Shrew").maxWidth(Double.MAX_VALUE).build()
      ).build()            
    );
    TitledPane viewPane = new TitledPane("Vegetables", 
      VBoxBuilder.create().style("-fx-padding: 10").spacing(10).children(
        ButtonBuilder.create().text("Eggplant").maxWidth(Double.MAX_VALUE).build(),
        ButtonBuilder.create().text("Carrot").maxWidth(Double.MAX_VALUE).build()
      ).build()            
    );

    // create an accordion, ensuring the currently expanded pane can not be clicked on to collapse.
    Accordion accordion = new Accordion();
    accordion.getPanes().addAll(adminPane, viewPane);
    accordion.expandedPaneProperty().addListener(new ChangeListener<TitledPane>() {
      @Override public void changed(ObservableValue<? extends TitledPane> property, final TitledPane oldPane, final TitledPane newPane) {
        if (oldPane != null) oldPane.setCollapsible(true);
        if (newPane != null) Platform.runLater(new Runnable() { @Override public void run() { 
          newPane.setCollapsible(false); 
        }});
      }
    });
    for (TitledPane pane: accordion.getPanes()) pane.setAnimated(false);
    accordion.setExpandedPane(accordion.getPanes().get(0));

    // layout the scene.
    StackPane layout = new StackPane();
    layout.setStyle("-fx-padding: 10; -fx-background-color: cornsilk;");
    layout.getChildren().add(accordion);
    primaryStage.setScene(new Scene(layout));
    primaryStage.show();
  }
}

Answer 2

这是确保手风琴永远不会完全崩溃的另一种解决方案。与@jewelsea 的原始答案的区别很小 - 我不喜欢默认向下箭头从打开的手风琴 TitledPane 面上消失的事实，因为它的“可折叠”属性被设置为 false。我更多地使用它来为我的界面实现更“自然”的感觉。

    /* Make sure the accordion can never be completely collapsed */
    accordeon.expandedPaneProperty().addListener((ObservableValue<? extends TitledPane> observable, TitledPane oldPane, TitledPane newPane) -> {
        Boolean expand = true; // This value will change to false if there's (at least) one pane that is in "expanded" state, so we don't have to expand anything manually
        for(TitledPane pane: accordeon.getPanes()) {
            if(pane.isExpanded()) {
                expand = false;
            }
        }
        /* Here we already know whether we need to expand the old pane again */
        if((expand == true) && (oldPane != null)) {
            Platform.runLater(() -> {
                accordeon.setExpandedPane(oldPane);
            });
        }
    });