Question

我有一个关于将选定日期从DatePicker传递到另一个FXML文件的问题。我已经看到类似线程中的代码，但我似乎无法理解它。

基本上我想从DatePicker（在DiscountController中）中选择一个日期，并能够在另一个FXML文件（在ConfirmController中）中检索所选日期并打印它。这是我到目前为止所做的。

任何人都可以告诉我这里做错了什么/在这里失踪了吗？

public class DiscountController implements Initializable {

    private final static DiscountController instance = new DiscountController();
    public static DiscountController getInstance() {
        return instance;
    }


    @FXML private DatePicker dp;
    @FXML private Label lblDate;

    public DatePicker getDp() {
        return dp;
    }


    //button to print the selected date in a label. This works fine
    @FXML private void ConfirmBtnAction (ActionEvent event) {
          lblDate.setText(dp.getValue().toString());
          }


  //button to move to next FXML screen
  @FXML private void nextBtnAction(ActionEvent event) {

    try{
     Parent parent = FXMLLoader.load(getClass().getResource("/appl/Confirm.fxml"));
     Stage stage = new Stage();
     Scene scene = new Scene(parent);
     stage.setScene(scene);
     stage.show();


     }
     catch(IOException e){
     }
}
    @Override
    public void initialize(URL url, ResourceBundle rb) {
    }    

}

fxml文件

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

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

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="ivikappl.DiscountController">
  <children>
    <Label contentDisplay="LEFT" layoutX="236.0" layoutY="33.0" prefHeight="42.0" prefWidth="133.0" text="Discount">
      <font>
        <Font size="28.0" />
      </font>
    </Label>
    <Button fx:id="btnNext" layoutX="525.0" layoutY="358.0" mnemonicParsing="false" onAction="#nextBtnAction" prefWidth="61.0" text="Next" />
    <Label layoutX="231.0" layoutY="158.0" prefHeight="21.0" prefWidth="69.0" text="Select Date" />
    <Label layoutX="404.0" layoutY="158.0" prefHeight="21.0" prefWidth="101.0" text="Select discount %" />
    <Label layoutX="54.0" layoutY="158.0" prefHeight="21.0" prefWidth="69.0" text="Product" />
      <DatePicker fx:id="dp" layoutX="189.0" layoutY="117.0" />
      <Label fx:id="lblDate" layoutX="219.0" layoutY="247.0" prefHeight="35.0" prefWidth="95.0" />
      <Button fx:id="btnConfirm" layoutX="241.0" layoutY="200.0" mnemonicParsing="false" onAction="#ConfirmBtnAction" text="Confirm" />
      <TextField layoutX="391.0" layoutY="117.0" />
      <Label fx:id="lblProduct" layoutX="22.0" layoutY="121.0" prefHeight="17.0" prefWidth="149.0" />
        </children>
</AnchorPane>

ConfirmController文件

public class ConfirmController implements Initializable  {


//button to fetch selected date from DiscountController and print it 
//Having a problem, here, this one doesn't work
@FXML private void btnFetchAction (ActionEvent event) {
   String A;
    A = DiscountController.getInstance().getDp().getValue().toString();
            System.out.println(A);
      }


    @Override
    public void initialize(URL url, ResourceBundle rb) {
        }    

}

和FXML

<?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="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="ivikappl.ConfirmController">
   <children>
      <Button layoutX="382.0" layoutY="74.0" mnemonicParsing="false" prefHeight="49.0" prefWidth="115.0" text="Generate barcode" textAlignment="CENTER" />
      <Label layoutX="91.0" layoutY="31.0" prefHeight="30.0" prefWidth="79.0" text="Summary">
         <font>
            <Font name="System Bold" size="12.0" />
         </font>
      </Label>
      <Label layoutX="40.0" layoutY="123.0" prefHeight="20.0" prefWidth="85.0" text="Productname">
         <font>
            <Font name="System Italic" size="12.0" />
         </font>
      </Label>
      <Label fx:id="lblDate" layoutX="40.0" layoutY="79.0" prefHeight="20.0" prefWidth="67.0">
         <font>
            <Font name="System Italic" size="12.0" />
         </font>
      </Label>
      <Label layoutX="40.0" layoutY="166.0" prefHeight="20.0" prefWidth="67.0" text="Discount">
         <font>
            <Font name="System Italic" size="12.0" />
         </font>
      </Label>
      <Button fx:id="btnFetch" layoutX="40.0" layoutY="236.0" mnemonicParsing="false" onAction="#btnFetchAction" text="Fetch" />
   </children>
</AnchorPane>

Answer 1

你不能在这里使用单例模式，因为FXMLLoader本质上是通过调用无参数构造函数创建一个DiscountController的实例（即不是通过调用DiscountController.getInstance()）。（如果你真的想要的话，你可以通过设置加载折扣FXML文件的FXMLLoader上的控制器工厂来实现这条路线，但是控制器成为单身人士真的没有意义。在很多情况下你真的需要它们的多个实例。而且还有更简单的方法来实现你想要做的事情。）

在ConfirmController中定义一个可以传递日期的方法：

public class ConfirmController {

    @FXML
    private Label lblDate ;

    public void setDate(LocalDate date) {
        lblDate.setText(date.toString());
    }

    // ... other code as before...
}

然后在加载FXML时调用它：

public class DiscountController implements Initializable {

    @FXML private DatePicker dp;

    // ...

    @FXML private void nextBtnAction(ActionEvent event) {

        try{
         FXMLLoader loader = new FXMLLoader(getClass().getResource("/appl/Confirm.fxml"));
         Parent parent = loader.load();
         ConfirmController confirmController = loader.getController();
         confirmController.setDate(dp.getValue());
         Stage stage = new Stage();
         Scene scene = new Scene(parent);
         stage.setScene(scene);
         stage.show();


         }
         catch(IOException e){
         }
    }

    // ...
}

有关其他一些方法，请参阅Passing Parameters JavaFX FXML。

从DatePicker检索日期并移至另一个FXML文件

1 个答案: