Use Region as a spacer-filler in a single HBox

[警告:我不是Java FX方面的专家.]

我问了a similar Question个，更狭隘地关注于一种只使用一个HBox而不是嵌套多个HBox对象来完成标签按钮-按钮布局的方法.

Answer there by makki saud alghamdi至少为您提供了部分可能的解决方案.答案是使用Region对象作为标签和按钮之间的空间，以填补空白，有效地将按钮向右推.

代码的关键行是:

// Mind the gap between label and buttons.
Region spacer = new Region ( );
HBox.setHgrow ( spacer , Priority.ALWAYS );

HBox rowBox = new HBox ( label , spacer , editButton , completedButton );

下面是一个完整的示例应用程序.

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;
import java.io.IOException;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.List;

public class HelloApplication  extends Application
{
    @Override
    public void start ( Stage stage ) throws IOException
    {
        record Event( String title , LocalDate when ) { }
        ObservableList < Event > events =
                FXCollections.observableList (
                        List.of (
                                new Event ( "A bit of text" , LocalDate.now ( ) ) ,
                                new Event ( "Even more text than that." , LocalDate.now ( ).plusDays ( 1 ) ) ,
                                new Event ( "Lots and lots and lots of text for a very long line." , LocalDate.now ( ).plusDays ( 2 ) )
                        )
                );
        ListView < Event > eventView = new ListView <> ( events );
        eventView.setCellFactory ( ( ListView < Event > listView ) -> new ListCell < Event > ( )
        {
            Button editButton = new Button ( "Edit" );
            Button completedButton = new Button ( "Completed" );
            Label label = new Label (  );
            Label labelTwo = new Label( );
            Region spacer = new Region ( );
            VBox vBox = new VBox(label, labelTwo);
            HBox rowBox = new HBox ( vBox , spacer , editButton , completedButton );            
            DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("MM/dd");
            {
                // Mind the gap between label and buttons.
                HBox.setHgrow ( spacer , Priority.ALWAYS );
                rowBox.setAlignment ( Pos.CENTER );
                rowBox.setSpacing ( 7 );
            }
                   
            
            @Override
            protected void updateItem ( Event item , boolean empty )
            {
                super.updateItem ( item , empty );
                if ( empty || item == null )
                {
                    setText ( null );
                    setGraphic ( null );
                } 
                else
                {                   
                    label.setText(item.title());
                    labelTwo.setText("\tDue: " + item.when().format(dateTimeFormatter));
                    editButton.setOnAction ( actionEvent ->
                    {                        
                        System.out.println ( "DEBUG - Edit the Event: " + item.title() );
                    });
                    completedButton.setOnAction ( actionEvent ->
                    {
                        System.out.println ( "DEBUG - Completed the Event: " + item.title());
                    });
                    
                    setGraphic ( rowBox );
                }
            }
        } );

        BorderPane pane = new BorderPane ( );
        pane.setCenter ( eventView );

        Scene scene = new Scene ( pane , 700 , 300 );
        stage.setScene ( scene );
        stage.setTitle ( "Schedule Example" );
        stage.show ( );
    }

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

还有一张截图.

我可能不会认为这个解决方案是完整的.如果用户缩小窗口的宽度，按钮将从窗口的右边缘消失.理想情况下，按钮在窗口内始终可见，过长的标签将被截断.我不知道那个问题的解决方案.

将域对象绑定到操作按钮

另外，最终我需要弄清楚如何将按钮与之对齐的元素发送到函数中，以便在按钮被按下时使用，如果有人对此有提示的话

将每个域对象绑定到按钮是一个与小部件布局相关的问题.因此，你应该就那个特定的问题单独提出一个问题.

但简单地说，…

请注意，向您的cell factory传递了对该项目的引用，该项目是您的Event类的对象，将由ListView显示.在这一行中:

protected void updateItem ( Event item , boolean empty ) … 

…第一个参数Event item是关键.请注意，在实例化每个Label时，我如何在对item.toString的调用中使用该引用.

Label label = new Label ( item.toString ( ) );

我们也可以在您的按钮操作处理程序中添加类似的调用.

Button editButton = new Button ( "Edit" );
Button completedButton = new Button ( "Completed" );
editButton.setOnAction ( ( ActionEvent actionEvent ) ->
{
    System.out.println ( "DEBUG - Edit the Event: " + item.toString ( ) );
} );
completedButton.setOnAction ( ( ActionEvent actionEvent ) ->
{
    System.out.println ( "DEBUG - Completed the Event: " + item.toString ( ) );
} );

顺便说一句，尤其是在学习的过程中，您可能会发现扩展lambdas中的参数类型很方便.这样做有助于让你的头脑保持清醒，准确地知道在每一个点上都有哪些物体在发挥作用.

所以这就是:

editButton.setOnAction ( ( ActionEvent actionEvent ) -> …

…而不是这样:

editButton.setOnAction ( actionEvent -> …