Center children in GridPane using CSS

问题

I have a GridPane populated with ToggleButtons. First row and column in that GridPane holds Text object labels.
I am unable to center the Text objects with the ToggleButtons so the text appears in the middle, using css.
(This answer shows how to achieve it by using GridPane.setHalignment(node, HPos.CENTER);).

MCVE if needed :

import javafx.application.Application;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.ToggleButton;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.Pane;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class GridTest extends Application {

    private static final int COLS = 5, ROWS = 3;

    @Override public void start(Stage stage) {
        Scene scene = new Scene(makeGrid());
        scene.getStylesheets().add(getClass().
                getResource("GridTest.css").toExternalForm());
        stage.setScene(scene);
        stage.show();
    }

    private Pane makeGrid() {

        GridPane grid = new GridPane();

        for(int rowIndex = 0; rowIndex < ROWS ; rowIndex++) {

            Node[] nodes = new Node[COLS];
            Node node;
            for(int colIndex = 0; colIndex < COLS ; colIndex++) {

                if (rowIndex == 0){ //col header;
                    String txt =  (colIndex == 0) ?
                            " " : String.valueOf(colIndex);
                    node = new Text(txt);
                }else if (colIndex == 0){//row header
                    node = new Text(String.valueOf(rowIndex));
                }else {
                    node= new ToggleButton();
                }
                nodes[colIndex]= node;
            }
            grid.addRow(rowIndex, nodes);
        }
        return grid;
    }

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

CSS:

Text{
    -fx-text-alignment: center;
}

GridPane {
    -fx-hpos:center ;
    -fx-hgap: 5;
    -fx-vgap: 5;
    -fx-padding:10;  
}

ToggleButton {  
    -fx-pref-width:30;
}

回答1:

Based on the comments posted by @ James_D and @fabian and previous answers there are two options to get the text labels centered.
One option, as posted in the question, does not use css. It requires slight modification of the makeGrid:

//see: https://stackoverflow.com/a/35438985/3992939
GridPane.setHalignment(node, HPos.CENTER);  //added line
nodes[colIndex]= node;

This solutions does not change the (non resizable) Text. It simple centers it within its GridPane parent column.

The other option involves changing the Text lables to Labels :

private Pane makeGrid() {

    GridPane grid = new GridPane();
    for(int rowIndex = 0; rowIndex < ROWS ; rowIndex++) {

        Node[] nodes = new Node[COLS];
        Node node;
        for(int colIndex = 0; colIndex < COLS ; colIndex++) {
            if (rowIndex == 0){ //col header;
                String txt =  (colIndex == 0) ? " " : String.valueOf(colIndex);
                node = new Label(txt);                      //** changed 
            }else if (colIndex == 0){//row header
                node = new Label(String.valueOf(rowIndex)); //** changed 
            }else {
                node= new ToggleButton();
            }
            nodes[colIndex]= node;
        }
        grid.addRow(rowIndex, nodes);
    }
    return grid;
}

And using css (or additional code) to set the label's width to maximum and center the text :

GridPane .label{
    -fx-alignment: center;
    -fx-max-width: Infinity;
}

GridPane {
    -fx-hgap: 5;
    -fx-vgap: 5;
    -fx-padding:10;  
}

ToggleButton {  
    -fx-pref-width:30;
}

来源：https://stackoverflow.com/questions/50470841/center-children-in-gridpane-using-css

标签

css

javafx

alignment

gridpane