即使更改后标签也不显示文本 (JavaFX)
Label not displaying text even after change (JavaFX)
我正在做一个项目,我需要显示一个 ListView
到另一个 Scene
的 Medicine 对象的信息。
用户将 select 来自 ListView
的药物,然后按 Button
以在下一个 Scene
中查看它的详细信息,这将由 Label
显示。现在的问题是,我传了信息,Label的文本属性变了(通过println和调试观察),但是Label
就是不显示变了的文本。
这是主要的
package app;
import app.data.MedicineData;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.input.MouseEvent;
import javafx.stage.Stage;
import org.w3c.dom.events.Event;
import java.io.IOException;
public class Pharmachine extends Application {
public static final double WIDTH = 480;
public static final double HEIGHT = 720;
@Override
public void start(Stage stage) throws Exception{
Parent homePage = FXMLLoader.load(getClass().getResource("homepage.fxml"));
Scene homePageScene = newDefaultScene(homePage);
stage.setResizable(false);
stage.setScene(homePageScene);
stage.setTitle("Pharmachine");
stage.show();
}
@Override
public void init(){
MedicineData.getInstance().loadData();
}
public static Scene newDefaultScene(Parent parent){
Scene scene = new Scene(parent, WIDTH, HEIGHT);
scene.addEventHandler(MouseEvent.MOUSE_CLICKED,
(mouseEvent) -> {
Node targetNode = scene.getFocusOwner();
if(targetNode != null && targetNode.isFocused()) {
if(targetNode.getParent() != null)
targetNode.getParent().requestFocus();
mouseEvent.consume();
}
}
);
return scene;
}
public static void navigateTo(ActionEvent actionEvent, String filename){
Stage mainWindow = (Stage) ((Node) actionEvent.getSource()).getScene().getWindow();
Scene currentScene = ((Node) actionEvent.getSource()).getScene();
try {
currentScene.setRoot(FXMLLoader.load(Pharmachine.class.getResource(filename)));
mainWindow.setScene(currentScene);
} catch(IOException e){
e.printStackTrace();
}
}
public static void main(String[] args){ launch(args); }
}
这是列表页面的 fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.ListView?>
<BorderPane xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml"
fx:controller="app.ListpageController" fx:id="pageRoot"
stylesheets="@styles/main.css">
<left>
<GridPane fx:id="listArea" alignment="CENTER">
<ListView fx:id="medicineList"
GridPane.rowIndex="1"/>
</GridPane>
</left>
<center>
<GridPane fx:id="buttonsArea" alignment="CENTER"
hgap="10" vgap="10">
<Button text="Back"
onAction="#displayHomePage"
GridPane.halignment="CENTER"/>
<Button text="Details"
onAction="#displayDetailsPage"
GridPane.rowIndex="1"
GridPane.halignment="CENTER"/>
</GridPane>
</center>
</BorderPane>
这是列表页面的控制器
package app;
import app.data.Medicine;
import app.data.MedicineData;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.control.Label;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.util.Callback;
import java.io.IOException;
public class ListpageController {
@FXML
private BorderPane pageRoot;
@FXML
private GridPane listArea;
@FXML
private GridPane buttonsArea;
@FXML
private ListView<Medicine> medicineList;
@FXML public void initialize(){
listArea.setMaxWidth(Pharmachine.WIDTH * 3/5);
medicineList.setMinWidth(listArea.getMaxWidth());
medicineList.setMinHeight(Pharmachine.HEIGHT);
medicineList.setItems(MedicineData.getInstance().getMedicines());
medicineList.setCellFactory(new Callback<>() {
@Override
public ListCell<Medicine> call(ListView<Medicine> medicineListView) {
ListCell<Medicine> listCell = new ListCell<>(){
@Override
public void updateItem(Medicine medicine, boolean empty){
super.updateItem(medicine, empty);
if(!empty){
HBox medName = new HBox(new Label(medicine.getName()));
HBox.setHgrow(medName, Priority.ALWAYS);
HBox medPrice = new HBox(new Label(String.format("RM%.2f", medicine.getPrice())));
HBox medLabel = new HBox(medName, medPrice);
setGraphic(medLabel);
}
}
};
listCell.setOnMouseClicked(
(mouseEvent) -> {
if(mouseEvent.getClickCount() == 2){
medicineList.getSelectionModel().clearSelection();
}
}
);
return listCell;
}
});
}
@FXML private void displayHomePage(ActionEvent actionEvent){
Pharmachine.navigateTo(actionEvent, "homepage.fxml");
}
@FXML private void displayDetailsPage(ActionEvent actionEvent){
FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("detailspage.fxml"));
try {
loader.load();
} catch(IOException e){
e.printStackTrace();
}
DetailspageController controller = loader.getController();
Medicine selectedMedicine = medicineList.getSelectionModel().getSelectedItem();
if(selectedMedicine != null) {
controller.setInfo(selectedMedicine);
Pharmachine.navigateTo(actionEvent, "detailspage.fxml");
}
}
}
这是下一个场景的 fxml(现在很简单)
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.text.Text?>
<BorderPane xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml"
fx:id="pageRoot" fx:controller="app.DetailspageController"
stylesheets="@styles/main.css">
<center>
<GridPane fx:id="detailsArea"
alignment="CENTER" hgap="10" vgap="10">
<Label text="Details"/>
<Text text="Name: "
GridPane.rowIndex="1"/>
<Label fx:id="medNameLabel" text="~"
GridPane.rowIndex="1" GridPane.columnIndex="1"/>
<Text text="Price: "
GridPane.rowIndex="2"/>
<Label fx:id="medPriceLabel" text="~"
GridPane.rowIndex="2" GridPane.columnIndex="1"/>
</GridPane>
</center>
</BorderPane>
这是场景的控制器
package app;
import app.data.Medicine;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import java.net.URL;
import java.util.ResourceBundle;
public class DetailspageController implements Initializable {
private Medicine selectedMedicine;
@FXML
private BorderPane pageRoot;
@FXML
private GridPane detailsArea;
@FXML
private Label medNameLabel;
@FXML
private Label medPriceLabel;
@Override
public void initialize(URL url, ResourceBundle rb){
}
public void setInfo(Medicine medicine){
selectedMedicine = medicine;
medNameLabel.setText(selectedMedicine.getName());
medPriceLabel.setText(String.format("RM%.2f", selectedMedicine.getPrice()));
System.out.println(medNameLabel.textProperty());
System.out.println(medNameLabel.getText());
medNameLabel.setStyle("-fx-background-color: red;");
}
}
帮助意义重大。谢谢:]
在您的 displayDetailsPage
方法中,您从 detailspage.fxml 加载场景,并通过调用控制器的 setInfo 方法更新其标签。
然后,您调用 Pharmachine.navigateTo,它再次加载 detailspage.xml 并用新加载的根替换场景根。您更新了第一个详细信息页面中的标签文本,但是第二个详细信息页面是全新的,因此没有这些变化。
navigateTo 方法中的第二个参数应该是 Parent 类型而不是字符串。 navigateTo 不应尝试加载任何 .fxml 文件;让那成为来电者的责任。
旁注:当列表的每个数据项都有多个属性时,您可能应该使用 TableView 而不是 ListView。
我正在做一个项目,我需要显示一个 ListView
到另一个 Scene
的 Medicine 对象的信息。
用户将 select 来自 ListView
的药物,然后按 Button
以在下一个 Scene
中查看它的详细信息,这将由 Label
显示。现在的问题是,我传了信息,Label的文本属性变了(通过println和调试观察),但是Label
就是不显示变了的文本。
这是主要的
package app;
import app.data.MedicineData;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.input.MouseEvent;
import javafx.stage.Stage;
import org.w3c.dom.events.Event;
import java.io.IOException;
public class Pharmachine extends Application {
public static final double WIDTH = 480;
public static final double HEIGHT = 720;
@Override
public void start(Stage stage) throws Exception{
Parent homePage = FXMLLoader.load(getClass().getResource("homepage.fxml"));
Scene homePageScene = newDefaultScene(homePage);
stage.setResizable(false);
stage.setScene(homePageScene);
stage.setTitle("Pharmachine");
stage.show();
}
@Override
public void init(){
MedicineData.getInstance().loadData();
}
public static Scene newDefaultScene(Parent parent){
Scene scene = new Scene(parent, WIDTH, HEIGHT);
scene.addEventHandler(MouseEvent.MOUSE_CLICKED,
(mouseEvent) -> {
Node targetNode = scene.getFocusOwner();
if(targetNode != null && targetNode.isFocused()) {
if(targetNode.getParent() != null)
targetNode.getParent().requestFocus();
mouseEvent.consume();
}
}
);
return scene;
}
public static void navigateTo(ActionEvent actionEvent, String filename){
Stage mainWindow = (Stage) ((Node) actionEvent.getSource()).getScene().getWindow();
Scene currentScene = ((Node) actionEvent.getSource()).getScene();
try {
currentScene.setRoot(FXMLLoader.load(Pharmachine.class.getResource(filename)));
mainWindow.setScene(currentScene);
} catch(IOException e){
e.printStackTrace();
}
}
public static void main(String[] args){ launch(args); }
}
这是列表页面的 fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.ListView?>
<BorderPane xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml"
fx:controller="app.ListpageController" fx:id="pageRoot"
stylesheets="@styles/main.css">
<left>
<GridPane fx:id="listArea" alignment="CENTER">
<ListView fx:id="medicineList"
GridPane.rowIndex="1"/>
</GridPane>
</left>
<center>
<GridPane fx:id="buttonsArea" alignment="CENTER"
hgap="10" vgap="10">
<Button text="Back"
onAction="#displayHomePage"
GridPane.halignment="CENTER"/>
<Button text="Details"
onAction="#displayDetailsPage"
GridPane.rowIndex="1"
GridPane.halignment="CENTER"/>
</GridPane>
</center>
</BorderPane>
这是列表页面的控制器
package app;
import app.data.Medicine;
import app.data.MedicineData;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.control.Label;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.util.Callback;
import java.io.IOException;
public class ListpageController {
@FXML
private BorderPane pageRoot;
@FXML
private GridPane listArea;
@FXML
private GridPane buttonsArea;
@FXML
private ListView<Medicine> medicineList;
@FXML public void initialize(){
listArea.setMaxWidth(Pharmachine.WIDTH * 3/5);
medicineList.setMinWidth(listArea.getMaxWidth());
medicineList.setMinHeight(Pharmachine.HEIGHT);
medicineList.setItems(MedicineData.getInstance().getMedicines());
medicineList.setCellFactory(new Callback<>() {
@Override
public ListCell<Medicine> call(ListView<Medicine> medicineListView) {
ListCell<Medicine> listCell = new ListCell<>(){
@Override
public void updateItem(Medicine medicine, boolean empty){
super.updateItem(medicine, empty);
if(!empty){
HBox medName = new HBox(new Label(medicine.getName()));
HBox.setHgrow(medName, Priority.ALWAYS);
HBox medPrice = new HBox(new Label(String.format("RM%.2f", medicine.getPrice())));
HBox medLabel = new HBox(medName, medPrice);
setGraphic(medLabel);
}
}
};
listCell.setOnMouseClicked(
(mouseEvent) -> {
if(mouseEvent.getClickCount() == 2){
medicineList.getSelectionModel().clearSelection();
}
}
);
return listCell;
}
});
}
@FXML private void displayHomePage(ActionEvent actionEvent){
Pharmachine.navigateTo(actionEvent, "homepage.fxml");
}
@FXML private void displayDetailsPage(ActionEvent actionEvent){
FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("detailspage.fxml"));
try {
loader.load();
} catch(IOException e){
e.printStackTrace();
}
DetailspageController controller = loader.getController();
Medicine selectedMedicine = medicineList.getSelectionModel().getSelectedItem();
if(selectedMedicine != null) {
controller.setInfo(selectedMedicine);
Pharmachine.navigateTo(actionEvent, "detailspage.fxml");
}
}
}
这是下一个场景的 fxml(现在很简单)
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.text.Text?>
<BorderPane xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml"
fx:id="pageRoot" fx:controller="app.DetailspageController"
stylesheets="@styles/main.css">
<center>
<GridPane fx:id="detailsArea"
alignment="CENTER" hgap="10" vgap="10">
<Label text="Details"/>
<Text text="Name: "
GridPane.rowIndex="1"/>
<Label fx:id="medNameLabel" text="~"
GridPane.rowIndex="1" GridPane.columnIndex="1"/>
<Text text="Price: "
GridPane.rowIndex="2"/>
<Label fx:id="medPriceLabel" text="~"
GridPane.rowIndex="2" GridPane.columnIndex="1"/>
</GridPane>
</center>
</BorderPane>
这是场景的控制器
package app;
import app.data.Medicine;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import java.net.URL;
import java.util.ResourceBundle;
public class DetailspageController implements Initializable {
private Medicine selectedMedicine;
@FXML
private BorderPane pageRoot;
@FXML
private GridPane detailsArea;
@FXML
private Label medNameLabel;
@FXML
private Label medPriceLabel;
@Override
public void initialize(URL url, ResourceBundle rb){
}
public void setInfo(Medicine medicine){
selectedMedicine = medicine;
medNameLabel.setText(selectedMedicine.getName());
medPriceLabel.setText(String.format("RM%.2f", selectedMedicine.getPrice()));
System.out.println(medNameLabel.textProperty());
System.out.println(medNameLabel.getText());
medNameLabel.setStyle("-fx-background-color: red;");
}
}
帮助意义重大。谢谢:]
在您的 displayDetailsPage
方法中,您从 detailspage.fxml 加载场景,并通过调用控制器的 setInfo 方法更新其标签。
然后,您调用 Pharmachine.navigateTo,它再次加载 detailspage.xml 并用新加载的根替换场景根。您更新了第一个详细信息页面中的标签文本,但是第二个详细信息页面是全新的,因此没有这些变化。
navigateTo 方法中的第二个参数应该是 Parent 类型而不是字符串。 navigateTo 不应尝试加载任何 .fxml 文件;让那成为来电者的责任。
旁注:当列表的每个数据项都有多个属性时,您可能应该使用 TableView 而不是 ListView。