JavaFX，GridPane：在GridPane的列中生成元素将保持所有列的宽度

在本例中，您需要将按钮的MaxWidth设置为Positive_Infinity.

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

import java.util.stream.Stream;

public class Tester extends Application {
    private static final int WIDTH = 300;
    private static final int HEIGHT = 400;

    @Override
    public void start(Stage stage) {
        GridPane pane = new GridPane();
        pane.setGridLinesVisible(true);
        pane.setAlignment(Pos.TOP_LEFT);
        pane.setHgap(10);
        pane.setVgap(10);
        pane.setPadding(new Insets(10, 10, 10, 10));

        Button cat = new Button("cat");
        Button monkey = new Button("monkey");
        Button elephant = new Button("elephant and lion");
        pane.add(cat, 0, 0);
        pane.add(monkey, 0, 1);
        pane.add(elephant, 0, 2);

        Stream.of(cat, monkey, elephant).forEach(btn -> btn.setMaxWidth(Double.POSITIVE_INFINITY));

        Scene scene = new Scene(pane, WIDTH, HEIGHT);
        stage.setScene(scene);
        stage.show();
    }
}