setWrapText(true) 不适用于 JavaFX 中的标签

Question

我在 JavaFX 中创建了一个 Label，其中包含很多文本。

Label l1 = new Label("\t\tC-Mark and Attendance Calculator is a simple "
            + "software to find both the C-Mark and monthly attendance "
            + "of students. Inorder to use the features of this software,"
            + " user has to create an account for him first. Then he should "
            + "login using the username and password. He will be able to "
            + "perform all the operations then. Further details are mentioned"
            + " in the 'HELP' section in the user home page.");
l1.setWrapText(true);
l1.setTextAlignment(TextAlignment.JUSTIFY);

在此代码中，setWrapText(true) 不起作用。为什么？我怎样才能让它发挥作用？

Answer 1

Label l1 = new Label("\t\tC-Mark and Attendance Calculator is a simple "
                + "software to find both the C-Mark and monthly attendance "
                + "of students. Inorder to use the features of this software,"
                + " user has to create an account for him first. Then he should "
                + "login using the username and password. He will be able to "
                + "perform all the operations then. Further details are mentioned"
                + " in the 'HELP' section in the user home page.");
        l1.setWrapText(true);
        l1.setTextAlignment(TextAlignment.JUSTIFY);

这是一个 SSCCE：

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.scene.text.TextAlignment;
import javafx.stage.Stage;

public class WrappedLabelExample extends Application {

    @Override
    public void start(Stage primaryStage) {
        Label l1 = new Label("\t\tC-Mark and Attendance Calculator is a simple "
                + "software to find both the C-Mark and monthly attendance "
                + "of students. Inorder to use the features of this software,"
                + " user has to create an account for him first. Then he should "
                + "login using the username and password. He will be able to "
                + "perform all the operations then. Further details are mentioned"
                + " in the 'HELP' section in the user home page.");
        l1.setWrapText(true);
        l1.setTextAlignment(TextAlignment.JUSTIFY);

        StackPane root = new StackPane(l1);
        root.setPadding(new Insets(10));
        Scene scene = new Scene(root, 400, 400);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

导致

Answer 2

我在 Scene Builder 中遇到了同样的问题，其他解决方案都不起作用。

我终于通过将“最小高度”设置为 USE_PREF_SIZE 并将“首选项高度”保持在 USE_COMPUTED_SIZE 来实现它。

这将转换为 FXML，并将 minHeight 属性设置为 -Infinity。

Answer 3

虽然上述解决方案可以工作，但我遇到的一个特殊问题是，如果将标签放置在 VBox 内，它不会包装 尽管设置了标签最大宽度并且 wrapText 是设置为真。在这种情况下，标签必须ALSO设置其首选项和最小高度才能开始换行，如果您在 VBox 中有多个标签并试图让它们工作，这可能会很烦人。

private VBox myCode() {
    VBox container = new VBox();
    int maxWidth = 200;
    container.setMaxWidth(maxWidth);

    Label one = new Label("This is very long");
    one.setMaxWidth(maxWidth);
    one.setPrefWidth(maxWidth);
    one.setWrapText(true);
    // Tailored to the text
    one.setMinHeight(100);
    one.setPrefHeight(100);

    Label two = new Label("This is also very long");
    two.setMaxWidth(maxWidth);
    two.setPrefWidth(maxWidth);
    two.setWrapText(true);
    // Tailored to the text
    two.setMinHeight(200);
    two.setPrefHeight(200);

    container.getChildren().addAll(one, two);
    return container;
}

为避免与此相关的麻烦，您可以使用 TextFlow 对象而不是标签，并将一个 Text 对象放入 TextFlow 中，因为它将包裹文本而无需担心它的高度应该是多少。

private static TextFlow aLabel(String... pString) {
     TextFlow textFlowLabel = new TextFlow();
     textFlowLabel.setMaxWidth(MAX_WIDTH);
     textFlowLabel.setPrefWidth(MAX_WIDTH);
     textFlowLabel.setTextAlignment(TextAlignment.JUSTIFY);
     for (String aString : pString) {
         textFlowLabel.getChildren().add(new Text(aString));
     }
     return textFlowLabel;
}

private VBox myCode() {
     VBox container = new VBox();
     int maxWidth = 200;
     container.setMaxWidth(maxWidth);
     
     TextFlow labelOne = aLabel("This is very long");
     TextFlow labelTwo = aLabel("This is also very long");
     container.getChildren().addAll(labelOne, labelTwo);
     return container;
}