JavaFX-DatePicker始终返回null
日期选择器在更改日期后未更新 我在寻找答案,我发现了这个话题: ,但它不起作用 DatePicker的我的侦听器:JavaFX-DatePicker始终返回null,java,javafx,datepicker,javafx-8,Java,Javafx,Datepicker,Javafx 8,日期选择器在更改日期后未更新 我在寻找答案,我发现了这个话题: ,但它不起作用 DatePicker的我的侦听器: public void datePickerListener() { this.datePicker = new DatePicker(); this.datePicker.setShowWeekNumbers(false); this.datePicker.setOnAction(event -> { LocalDate date =
public void datePickerListener() {
this.datePicker = new DatePicker();
this.datePicker.setShowWeekNumbers(false);
this.datePicker.setOnAction(event -> {
LocalDate date = this.datePicker.getValue();
System.out.println("Selected date: " + date);
});
}
此外,我尝试在没有侦听器的情况下获取数据,如:
public void searchAvailableAppointments() {
LocalDate date;
String date2;
date = this.datePicker.getValue();
date2 = this.datePicker.getEditor().getText();
System.out.println(date);
System.out.println(date2);
}
也许有人有类似的问题,并找到了解决办法
EDIT1:
package sample;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.DatePicker;
import java.net.URL;
import java.time.LocalDate;
import java.util.ResourceBundle;
public class Controller implements Initializable {
@FXML
DatePicker datePicker;
@Override
public void initialize(URL location, ResourceBundle resources) {
this.datePicker = new DatePicker();
}
public void pressButton() {
LocalDate date;
date = datePicker.getValue();
System.out.println(date);
}
}
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.DatePicker?>
<?import javafx.scene.layout.AnchorPane?>
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="142.0" prefWidth="504.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<children>
<DatePicker fx:id="datePicker" layoutX="65.0" layoutY="58.0" prefHeight="25.0" prefWidth="295.0" />
<Button layoutX="387.0" layoutY="59.0" mnemonicParsing="false" onAction="#pressButton" prefHeight="25.0" prefWidth="80.0" text="Print result" />
</children>
</AnchorPane>
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
我创建了一个简单的项目来检查DatePicker的行为:
public void datePickerListener() {
this.datePicker = new DatePicker();
this.datePicker.setShowWeekNumbers(false);
this.datePicker.setOnAction(event -> {
LocalDate date = this.datePicker.getValue();
System.out.println("Selected date: " + date);
});
}
控制器类:
package sample;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.DatePicker;
import java.net.URL;
import java.time.LocalDate;
import java.util.ResourceBundle;
public class Controller implements Initializable {
@FXML
DatePicker datePicker;
@Override
public void initialize(URL location, ResourceBundle resources) {
this.datePicker = new DatePicker();
}
public void pressButton() {
LocalDate date;
date = datePicker.getValue();
System.out.println(date);
}
}
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.DatePicker?>
<?import javafx.scene.layout.AnchorPane?>
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="142.0" prefWidth="504.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<children>
<DatePicker fx:id="datePicker" layoutX="65.0" layoutY="58.0" prefHeight="25.0" prefWidth="295.0" />
<Button layoutX="387.0" layoutY="59.0" mnemonicParsing="false" onAction="#pressButton" prefHeight="25.0" prefWidth="80.0" text="Print result" />
</children>
</AnchorPane>
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
FXML文件:
package sample;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.DatePicker;
import java.net.URL;
import java.time.LocalDate;
import java.util.ResourceBundle;
public class Controller implements Initializable {
@FXML
DatePicker datePicker;
@Override
public void initialize(URL location, ResourceBundle resources) {
this.datePicker = new DatePicker();
}
public void pressButton() {
LocalDate date;
date = datePicker.getValue();
System.out.println(date);
}
}
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.DatePicker?>
<?import javafx.scene.layout.AnchorPane?>
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="142.0" prefWidth="504.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<children>
<DatePicker fx:id="datePicker" layoutX="65.0" layoutY="58.0" prefHeight="25.0" prefWidth="295.0" />
<Button layoutX="387.0" layoutY="59.0" mnemonicParsing="false" onAction="#pressButton" prefHeight="25.0" prefWidth="80.0" text="Print result" />
</children>
</AnchorPane>
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
但是我仍然不知道如何使它工作。您不应该在
initialize()
中重新初始化日期选择器。当FXMLLoader加载fxml时,它会实例化所有字段并将它们注入到引用中,这些引用用@fxml
注释
如果重新初始化该字段,对视图上呈现的原始对象的引用将丢失,并且您正在使用对新创建对象的引用,因此从该对象获取的值将始终为null
@Override
public void initialize(URL location, ResourceBundle resources) {
// this.datePicker = new DatePicker(); <-- Should not exist
}
@覆盖
公共void初始化(URL位置、ResourceBundle资源){
//this.datePicker=new datePicker();你说得完全正确!我没想到问题的解决这么简单,非常感谢!)