Creating a scene using both FXML and the Controller in JavaFX

问题

I've created a 9x9 GridPane in SceneBuilder, and I want to add individual TextFields to each cell. I'm certain there are other methods for creating a large table like this, but I'm not looking for a different way to do this (this is part of my learning experience). I don't want to add TextFields in FXML/SceneBuilder; I want to keep track of them in an array so I can access their individual values, so I want to create them one at a time in the Controller and then add them to the array as well as to each cell of the GridPane.

Here is the part of my controller that attempts to add TextFields (I tried creating them before adding them to the array):

@FXML
private GridPane gridPane;
private TextField myTextField[][] = new TextField[9][9];
.
.
.
@Override
public void initialize(URL url, ResourceBundle rb) {
  for (int i = 0; i < 9; ++i){
        for (int j = 0; j < 9; ++j){

            TextField tempTextField = new TextField();
            Font myFont = new Font("System",38);
            tempTextField.setFont(myFont);
            tempTextField.setText(i + ", " + j);
            tempTextField.setPrefSize(70, 70);
            myTextField[i][j] = tempTextField;
            gridPane.add(tempTextField,i,j);
            System.out.println("TextField " +i+j+" Created!");
        }
    } 
}

I don't get an error before runtime and the scene is not updated.

EDIT: I have looked at the StackTrace and noticed that I'm getting a Null Pointer at

gridPane.add(tempTextField,i,j);

FXML File:

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.text.*?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane id="AnchorPane" prefHeight="654.0" prefWidth="747.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8" fx:controller="sudokusolver.FXMLDocumentController">
    <children>
      <BorderPane prefHeight="654.0" prefWidth="747.0">
         <center>
            <GridPane fx:id="gridPane" gridLinesVisible="true" prefHeight="198.0" prefWidth="200.0" BorderPane.alignment="CENTER">
               <columnConstraints>
              <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                  <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
               </columnConstraints>
               <rowConstraints>
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                  <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
               </rowConstraints>
            </GridPane>
         </center>
         <bottom>
            <HBox alignment="CENTER" prefHeight="40.0" prefWidth="747.0" BorderPane.alignment="CENTER">
               <children>
                  <FlowPane prefHeight="200.0" prefWidth="200.0">
                     <children>
                        <Button fx:id="loadButton" alignment="CENTER" contentDisplay="CENTER" minHeight="-Infinity" minWidth="-Infinity" onAction="#setGrid" prefHeight="35.0" prefWidth="100.0" text="Load Board" />
                          <Button fx:id="solveButton" alignment="CENTER" contentDisplay="CENTER" minHeight="-Infinity" minWidth="-Infinity" onAction="#sudokuSolve" prefHeight="35.0" prefWidth="100.0" text="Solve" />
                     </children>
                  </FlowPane>
               </children>
            </HBox>
         </bottom>
      </BorderPane>
    </children>
</AnchorPane>

回答1:

Try implementing the javafx.fxml.Initializable interface in your controller and move the setGrid() logic to the method that comes with it.

来源：https://stackoverflow.com/questions/46545512/creating-a-scene-using-both-fxml-and-the-controller-in-javafx

标签

java

javafx

fxml

scenebuilder