JavaFX TextPane 不显示更新的文本

Question

我有一个 Pane (下面的所有代码)，其中包含一个带有 2 个子 Pane (VisualPane 和 TextPane)的 HBox。当有人按 ENTER 或 SPACE 时，我希望程序打印“Enter Pressed”。和“空间受压”。分别。当按下 ESCAPE 时，我希望应用程序关闭。

TextPane 由带有私有(private) TextArea 的 Pane 组成。使用 push(String message) 方法，TextArea 被清除，然后填充新消息。

但是，当您按 Enter 或 Space 时，什么也没有发生。无论您按按钮多少次，“文本”都会在控制台中打印一次。然而，每当按下 Escape 时，程序仍然会退出。

为什么push()方法会“卡住”TextArea？

代码:

public class GamePane extends Pane {

  private VBox content;
  private HBox textBox;

  private VisualPane visualPane;
  private TextPane textPane;

  public GamePane(){
    initialize();
  }

  private void initialize(){
    this.content = new VBox();
    getChildren().add(content);
    this.textBox = new HBox();

    this.visualPane = new VisualPane();
    this.textPane = new TextPane();

    content.getChildren().add(visualPane);
    content.getChildren().add(textBox);
    textBox.getChildren().add(textPane);

    this.setOnKeyPressed(e -> {
      switch (e.getCode()){
        case ENTER:
          this.textPane.push("Button pressed.");
          break;

        case SPACE:
          this.textPane.push("Button pressed.");
          break;

        case ESCAPE:
          Platform.exit();
          break;
      }
    });
  }
}

public class TextPane extends Pane {

  private TextArea textArea;

  public TextPane(){
    initialize();
    push("Text");
  }

  private void initialize(){
    this.textArea = new TextArea();
    textArea.setMinWidth(Constants.width);
    textArea.setMinHeight(Constants.height * 4 / 11);

    textArea.setEditable(false);
    textArea.setStyle("-fx-font-size: 3em;");

    getChildren().add(textArea);
  }

  public void push(String message){
    textArea.clear();
    textArea.setText(message);
    System.out.println("Text");
  }
}

附注:

GamePane 有一个 HBox 文本框，用于放置要添加的内容。

Answer 1

将 this.setOnkeyPressed(..) 更改为 this.setOnKeyReleased(..)。

如果程序启动时您的节点没有焦点，您可能还需要添加 this.requestFocus();。

import javafx.application.Platform;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;

public class GamePane extends Pane
{

    private VBox content;
    private HBox textBox;

    private VisualPane visualPane;
    private TextPane textPane;

    public GamePane()
    {
        initialize();
    }

    private void initialize()
    {
        this.content = new VBox();
        getChildren().add(content);
        this.textBox = new HBox();

        this.visualPane = new VisualPane();
        this.textPane = new TextPane();

        content.getChildren().add(visualPane);
        content.getChildren().add(textBox);
        textBox.getChildren().add(textPane);

        this.setOnKeyReleased(e -> {//Change here!
            switch (e.getCode()) {

                case ENTER:
                    this.textPane.push("Enter pressed.");
                    break;

                case SPACE:
                    this.textPane.push("Space pressed.");
                    break;

                case ESCAPE:
                    System.out.println("escaped pressed");
                    Platform.exit();
                    break;
            }
        });

        this.requestFocus();//Change here!
    }
}

您还知道为什么 OnKeyPressed 的行为与 OnKeyReleased 不同吗？

This answer is from the JavaDocs.

"Key typed" events are higher-level and generally do not depend on the platform or keyboard layout. They are generated when a Unicode character is entered, and are the preferred way to find out about character input. In the simplest case, a key typed event is produced by a single key press (e.g., 'a'). Often, however, characters are produced by series of key presses (e.g., SHIFT + 'a'), and the mapping from key pressed events to key typed events may be many-to-one or many-to-many. Key releases are not usually necessary to generate a key typed event, but there are some cases where the key typed event is not generated until a key is released (e.g., entering ASCII sequences via the Alt-Numpad method in Windows). No key typed events are generated for keys that don't generate Unicode characters (e.g., action keys, modifier keys, etc.).