java - 是否可以在 StackPane 中添加 Hbox？

Question

如您所见，我是一名初级开发人员，也是 stackOverflow 社区的新人。所以请不要告诉我我很蠢(或者我至少不知道为什么:))

我正在用 javaFx 编写一个小应用程序，但我遇到了一个小问题，我花了整个下午的时间来解决这个问题。

所以我有这个类(class)的程序:

package glintSG.view.mainPane;

 import java.awt.Dimension;

 import javafx.geometry.Pos;
 import javafx.scene.layout.HBox;
 import javafx.scene.text.Text;

public class CountDown extends HBox {

private Text countDownLabel;

public CountDown() {
    super();        
}   

public HBox buildCountDown() {
    HBox hb = new HBox();
    hb.setId("countDownBox");
    countDownLabel = new Text();
    countDownLabel.setId("countdownlabel-SG");
    //position of the count down adapted to the screen size
    relocateCountDown();    
    countDownLabel.getStyleClass().add("countdownlabel-SG");
    hb.getChildren().add(countDownLabel);
    hb.setAlignment(Pos.BASELINE_LEFT);
    return hb;      
}

public Text getCountDownLabel() {
    return countDownLabel;
}   

public void relocateCountDown() {
    countDownLabel.setTranslateX(Main.getWindowWidth()/2);      
}
}

现在，如果我在我看来它正在工作:

package glintSG.view;

public class SGView  {

private EnterHeadingPane enterHeadingPane;
private CountDown countDown;

@Override
public void preInit() {
    countDown = new CountDown();
    enterHeadingPane = new EnterHeadingPane();
}

@Override
public void init() {
getRootNode().getChildren().add(countDown.buildCountDown());
getRootNode().getChildren().add(enterHeadingPane.buildEnterCap());
}
}

(如您所见，我确实减少了类(class)，以便您更具可读性，如果您需要更多有关类(class)的信息，请不要犹豫)

但是如果我这样做它就会起作用。我不明白的是，当我不想将倒计时放在主图像中但在子堆栈 Pane 中时，什么也没有显示。如果我把倒计时放在这个类中:

package glintSG.view.mainPane;

public class EnterHeadingPane extends StackPane {

private Group group;

private Button tryButtonCAP;
private TextField inputTextCAP;
private Text textLabel;
private CountDown countDown;
private DifficultyLvlBox diffLvl;

private double textFieldPaddingTop = 7.0;
private double textFieldPaddingBot = 09.0;
private double textFieldPaddingLeft = 10.0;
private double textFieldPaddingRight = 10.0;

private double ButtonPaddingTop = 10.0;
private double ButtonPaddingBot = 10.0;
private double ButtonPaddingLeft = 10.0;
private double ButtonPaddingRight = 10.0;

private CustomTextField capTextField;
private boolean isWarningHere = false;

private Dimension dimension = java.awt.Toolkit.getDefaultToolkit().getScreenSize();


public EnterHeadingPane() {
    super();
    this.getStyleClass().add("glint-title-window");
}

public StackPane buildEnterCap() {
    final StackPane enterCap = new StackPane();
    enterCap.setId("enterCapLayer");
    textLabel = buildTextLabel();
    inputTextCAP = buildTextFieldCap();
    tryButtonCAP = buildCapButton();
    countDown =buildCountDown();
    group = new Group();
    group.getChildren().add(tryButtonCAP);
    group.getChildren().add(inputTextCAP);
    group.getChildren().add(textLabel);
    group.getChildren().add(countDown);
    group.getChildren().add(diffLvl);
    group.setTranslateX(getScreenWidth() - 
          textLabel.getLayoutBounds().getWidth() - 50);
    group.setTranslateY(900);
    enterCap.getChildren().add(group);
    return enterCap;
}
//well i write the methods buildTextLabel etc.

private CountDown buildCountDown() {
    countDown = new CountDown();
    countDown.setId("countDown-SG");
    countDown.buildCountDown();
    countDown.setAlignment(Pos.CENTER);
    return countDown;
}
}

如果我这样做了，我的倒计时就不会被打印出来。为什么？

所以我认为主要问题是:是否可以将 hbox 放入堆栈 Pane 中，但我认为可以。所以我需要你帮助我:)如果有人知道为什么，请帮助我:)

Answer 1

在您的第一个示例中，它可以工作，因为您使用了

getRootNode().getChildren().add(countDown.buildCountDown());

当您调用 countDown.buildCountDown() 时，您将创建一个新的 HBox 并返回它。

在第二个示例中

private CountDown buildCountDown() {
    countDown = new CountDown();
    countDown.setId("countDown-SG");
    countDown.buildCountDown();
    countDown.setAlignment(Pos.CENTER);
    return countDown;
}

它不起作用，因为您返回了扩展 HBox 但为空的 CountDown 对象。

您实际上在 CountDown 类中犯了一个错误。

您应该使用倒计时类作为 HBox，如下所示:

public class CountDown extends HBox {

    private Text countDownLabel;

    public CountDown() {
        super();
        // Initializes your CountDown.
        buildCountDown();
    }

    public void buildCountDown() {
        // Not needed to instantiate a new HBox, your countdown object is extending this kind of Node
        this.setId("countDownBox");
        countDownLabel = new Text();
        countDownLabel.setId("countdownlabel-SG");

        //position of the count down adapted to the screen size
        relocateCountDown();

        countDownLabel.getStyleClass().add("countdownlabel-SG");
        // Add the label to your CountDown object.
        this.getChildren().add(countDownLabel);
        this.setAlignment(Pos.BASELINE_LEFT);
    }


    public Text getCountDownLabel() {
        return countDownLabel;
    }


    public void relocateCountDown() {
        countDownLabel.setTranslateX(Main.getWindowWidth()/2);      
    }
}

当您实例化 CountDown 对象时，您可以将其添加到您的 Group 或 StackPane 中。

或者您可以使用对象初始化 HBox 属性并通过 getter 检索它:

public class CountDown {

    private Text countDownLabel;

    private HBox container;

    public CountDown() {
        super();
        // Initializes your CountDown.
        buildCountDown();
    }

    // Your method
    public void buildCountDown() {
        container = new HBox();
        container.setId("countDownBox");
        countDownLabel = new Text();
        countDownLabel.setId("countdownlabel-SG");

        //position of the count down adapted to the screen size
        relocateCountDown();

        countDownLabel.getStyleClass().add("countdownlabel-SG");
        container.getChildren().add(countDownLabel);
        container.setAlignment(Pos.BASELINE_LEFT);
    }

    // You can access to your HBox here
    public HBox getContainer() {
        return container;
    }

    public Text getCountDownLabel() {
        return countDownLabel;
    }

    public void relocateCountDown() {
        countDownLabel.setTranslateX(Main.getWindowWidth()/2);      
    }
}

Hbox“容器”将在对象 CountDown 的同时初始化，因为在 CountDown 构造函数中调用 buildCountDown 方法。您可以通过 getter CountDown#getContainer() 访问它。