javafx.fxml.LoadException 尝试在 TableView JavaFX 中显示对象列表时
javafx.fxml.LoadException when trying to display a list of objects in a TableView JavaFX
我正在尝试在 JavaFX table 中显示对象列表，但在遍历要添加到 table 的对象时，我将 运行 保留在 JavaFX 异常中，确实任何人都知道可能是什么原因造成的，我已经尝试了 ObservableLists 的几种不同实现，但它们都看到产生相同的结果，我的结论是 class 或 .fxml 文件可能存在错误。提前致谢。
JavaFX:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.image.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.text.*?>
<BorderPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="HomePageController">
<left>
<AnchorPane prefHeight="400.0" prefWidth="200.0" style="-fx-background-color: #c7a4ff;" BorderPane.alignment="CENTER">
<children>
<Label fx:id="userLabel" alignment="TOP_CENTER" contentDisplay="CENTER" text="Hello <User>" textAlignment="CENTER" textFill="WHITE">
<font>
<Font name="Segoe UI Semilight" size="24.0" />
</font>
<padding>
<Insets bottom="10.0" left="25.0" right="25.0" top="10.0" />
</padding>
</Label>
<padding>
<Insets bottom="10.0" left="25.0" right="25.0" top="10.0" />
</padding>
</Label>
<Button layoutY="60.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Home" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="120.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Diet" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="180.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Workout" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="240.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Groups" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="300.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="User Information" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
</children>
</AnchorPane>
</left>
<right>
<AnchorPane prefHeight="400.0" prefWidth="394.0" BorderPane.alignment="CENTER">
<children>
<Label alignment="TOP_CENTER" contentDisplay="CENTER" layoutX="148.0" text="Home" textAlignment="CENTER" textFill="#aa80ff">
<font>
<Font name="Segoe UI Semilight" size="24.0" />
</font>
<padding>
<Insets bottom="10.0" left="10.0" right="25.0" top="10.0" />
</padding>
</Label>
<Label alignment="TOP_CENTER" contentDisplay="CENTER" layoutX="14.0" layoutY="55.0" text="My Goals" textAlignment="CENTER" textFill="#aa80ff">
<font>
<Font name="Segoe UI Semilight" size="18.0" />
</font>
<padding>
<Insets bottom="10.0" left="10.0" right="25.0" top="10.0" />
</padding>
</Label>
<TableView fx:id="tbData" layoutX="14.0" layoutY="102.0" prefHeight="200.0" prefWidth="360.0" style="-fx-background-color: #ffffff;">
<columns>
<TableColumn fx:id="goalName" prefWidth="160.0" text="Name" />
<TableColumn fx:id="goalDate" prefWidth="50.0" text="Date" />
<TableColumn fx:id="goalStatus" prefWidth="75.0" text="Status" />
<TableColumn fx:id="goalGroups" prefWidth="10.0" text="Groups"/>
</columns>
</TableView>
</children>
</AnchorPane>
</right>
<bottom>
<AnchorPane prefHeight="50.0" prefWidth="600.0" style="-fx-background-color: #c7a4ff;" BorderPane.alignment="CENTER">
<children>
<ImageView fitHeight="30.0" fitWidth="30.0" layoutX="380.0" layoutY="10.0" pickOnBounds="true" preserveRatio="true">
<image>
<Image url="@img/add_box.png" />
</image>
</ImageView>
<Button graphicTextGap="0.0" layoutX="380.0" layoutY="10.0" mnemonicParsing="false" onAction="#openSelectGoalTypePage" opacity="0.0" prefHeight="30.0" prefWidth="30.0" />
<ImageView fitHeight="30.0" fitWidth="30.0" layoutX="300.0" layoutY="10.0" pickOnBounds="true" preserveRatio="true">
<image>
<Image url="@img/mode_edit.png" />
</image>
</ImageView>
<Button graphicTextGap="0.0" layoutX="300.0" layoutY="10.0" mnemonicParsing="false" onAction="#openEditGoalPage" opacity="0.0" prefHeight="30.0" prefWidth="30.0" />
<ImageView fitHeight="30.0" fitWidth="30.0" layoutX="460.0" layoutY="10.0" pickOnBounds="true" preserveRatio="true">
<image>
<Image url="@img/delete.png" />
</image>
</ImageView>
<Button graphicTextGap="0.0" layoutX="460.0" layoutY="10.0" mnemonicParsing="false" onAction="#removeTableItem" opacity="0.0" prefHeight="30.0" prefWidth="30.0" />
</children>
</AnchorPane>
</bottom>
</BorderPane>
控制者：
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.stage.Stage;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
public class HomePageController extends BaseController implements Initializable {
@FXML
private TableView<Goal> tbData = new TableView<>();
@FXML
public TableColumn<Goal, String> goalName;
@FXML
public TableColumn<Goal, String> goalDate;
@FXML
public TableColumn<Goal, String> goalStatus;
@FXML
public TableColumn<Goal, String> goalGroups;
/*@FXML
private Label userLabel;*/
//allow user to select a table item/row and delete it using the delete button
public void removeTableItem(){
}
public void openSelectGoalTypePage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("SelectGoalType.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openAddGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
//if user selects weight goal then open AddWeightGoal page
//else if user selects workout goal then open AddWorkoutGoal page
root = FXMLLoader.load(getClass().getResource("AddWeightGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openEditGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("EditGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
tbData = new TableView<>();
TableColumn<Goal, String> goalName = new TableColumn<>("GoalName");
goalName.setCellValueFactory(new PropertyValueFactory<>("goalName"));
TableColumn<Goal, String> goalDate = new TableColumn<>("GoalDate");
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalDate"));
TableColumn<Goal, String> goalStatus = new TableColumn<>("GoalStatus");
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalStatus"));
TableColumn<Goal, String> goalGroups = new TableColumn<>("GoalGroups");
goalGroups.setCellValueFactory(new PropertyValueFactory<>("goalGroups"));
tbData.getColumns().add(goalName);
tbData.getColumns().add(goalDate);
tbData.getColumns().add(goalStatus);
tbData.getColumns().add(goalGroups);
tbData.setItems(getGoals());
}
private ObservableList<Goal> getGoals(){
ObservableList<Goal> goals = FXCollections.observableArrayList();
for(int i = 0; i < user.getGoals().size(); i++){
goals.add(user.getGoals().get(i));
}
return goals;
}
}
目标Class：
import java.io.Serial;
import java.io.Serializable;
public class Goal implements Serializable {
@Serial
private static final long serialVersionUID = 1L;
public String getGoalName() {
return goalName;
}
public void setGoalName(String goalName) {
this.goalName = goalName;
}
public String getGoalDate() {
return goalDate;
}
public void setGoalDate(String goalDate) {
this.goalDate = goalDate;
}
public String getGoalStatus() {
return goalStatus;
}
public void setGoalStatus(String goalStatus) {
this.goalStatus = goalStatus;
}
public String getGoalGroups() {
return goalGroups;
}
public void setGoalGroups(String goalGroups) {
this.goalGroups = goalGroups;
}
public Goal(String goalName, String goalDate, String goalStatus, String goalGroups) {
this.goalName = goalName;
this.goalDate = goalDate;
this.goalStatus = goalStatus;
this.goalGroups = goalGroups;
}
String goalName;
String goalDate;
String goalStatus;
String goalGroups;
}
编辑：
我做了更多的调试，当我用一个 try-catch 块包围它时，它似乎从基本控制器指向我的用户对象为 null，尽管我相信我将它传递给了控制器持有用户对象的基本控制器，以及我用来传递用户对象的调用（在作为参数传递之前确认用户没有问题）。我似乎得到的唯一堆栈跟踪是加载程序，这是来自 try catch:java.lang.NullPointerException: Cannot invoke "User.getGoals()" because "this.user" is null :
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.stage.Stage;
import java.io.IOException;
public class BaseController {
User user;
Parent root;
Stage stage;
Scene scene;
@FXML
Label userLabel;
//default constructor
public BaseController(){
}
void setUser(User user){
this.user = user;
userLabel.setText(user.getUsername());
}
//connect to current user once logged in
/*
public BaseController(User user){
displayUsername(User);
}*/
//display current logged in user's first name
/*
private void displayUsername(User user){
userLabel.setText(user.firstName);
}*/
/**
* Menu Functions just in case
*/
// public void openHomePage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("HomePage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openDietPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("DietPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openWorkoutPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("WorkoutPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openGroupsPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("GroupsPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openUserPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("UserPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
public void MenuSwitch(javafx.event.ActionEvent actionEvent) throws IOException{
String text = ((Button)actionEvent.getSource()).getText();
String filename="";
switch(text){
case "Home":
filename="HomePage.fxml";break;
case "Diet":
filename="DietPage.fxml";break;
case "Workout":
filename="WorkoutPage.fxml";break;
case "Groups":
filename="GroupsPage.fxml";break;
case "User Information":
filename="UserPage.fxml";break;
case "Edit group":
filename="EditGroupPage.fxml"; break;
case "Create group":
filename="CreateGroupPage.fxml";break;
case "Add Diet Item":
filename="AddDietItemPage.fxml"; break;
case "EditWorkoutPage":
filename="EditWorkoutPage.fxml";break;
case "AddWorkoutPage":
filename="AddWorkoutPage.fxml";break;
case "EditUserPage":
filename="EditUserPage.fxml";break;
}
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource(filename));
Parent root = (Parent) fxmlLoader.load();
BaseController baseController = fxmlLoader.getController();
System.out.println(user);
baseController.setUser(user);
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
}
来自传递用户对象的前一个控制器：
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("HomePage.fxml"));
Parent root = (Parent) fxmlLoader.load();
HomePageController controller = fxmlLoader.getController();
controller.setUser(newUser);
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
谢谢！
编辑二：
完整堆栈跟踪：
java.lang.NullPointerException: Cannot invoke "User.getGoals()" because "this.user" is null
java.lang.NullPointerException: Cannot invoke "User.getGoals()" because "this.user" is null
at HomePageController.initialize(HomePageController.java:75)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2655)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:2517)
at UserLoginController.login(UserLoginController.java:108)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:76)
at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at javafx.base/com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:273)
at javafx.fxml/com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:83)
at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1857)
at javafx.fxml/javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1729)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Node.fireEvent(Node.java:8886)
at javafx.controls/javafx.scene.control.Button.fire(Button.java:203)
at javafx.controls/com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:208)
at javafx.controls/com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:247)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Scene$MouseHandler.process(Scene.java:3856)
at javafx.graphics/javafx.scene.Scene.processMouseEvent(Scene.java:1851)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2584)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:409)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:299)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent(GlassViewEventHandler.java:447)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:412)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:446)
at javafx.graphics/com.sun.glass.ui.View.handleMouseEvent(View.java:556)
at javafx.graphics/com.sun.glass.ui.View.notifyMouse(View.java:942)
at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication.lambda$runLoop(GtkApplication.java:277)
at java.base/java.lang.Thread.run(Thread.java:832)
java.sql.SQLException: The prepared statement has been finalized
控制器的initialize()方法在FXMLLoader.load()的执行过程中被调用，所以initialize()，因此getGoals()在之前被调用[=40] =] 你打电话给 setUser(...)。因此 user 在您尝试调用 user.getGoals().
时为空
要在您设置的结构中修复此问题，您需要在调用 setUser(...) 时填充 table 列表。您可以在子类中使用重写的 setUser(...) 方法来做到这一点。
另请注意，初始化 @FXML 注释字段总是错误的（因为它们由 FXMLLoader 初始化为 FXML 文件中定义的元素）。所以你的控制器应该看起来像这样：
public class HomePageController extends BaseController implements Initializable {
@FXML
private TableView<Goal> tbData ;
@FXML
public TableColumn<Goal, String> goalName;
@FXML
public TableColumn<Goal, String> goalDate;
@FXML
public TableColumn<Goal, String> goalStatus;
@FXML
public TableColumn<Goal, String> goalGroups;
/*@FXML
private Label userLabel;*/
//allow user to select a table item/row and delete it using the delete button
public void removeTableItem(){
}
public void openSelectGoalTypePage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("SelectGoalType.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openAddGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
//if user selects weight goal then open AddWeightGoal page
//else if user selects workout goal then open AddWorkoutGoal page
root = FXMLLoader.load(getClass().getResource("AddWeightGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openEditGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("EditGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
goalName.setCellValueFactory(new PropertyValueFactory<>("goalName"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalDate"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalStatus"));
goalGroups.setCellValueFactory(new PropertyValueFactory<>("goalGroups"));
}
@Override
void setUser(User user){
super.setUser(user);
tbData.setItems(getGoals());
}
private ObservableList<Goal> getGoals(){
return FXCollections.observableList(user.getGoals());
}
}
一种更标准的方法是使用 MVC 类型的设计，其中用户由 ObjectProperty<User> 表示，您可以观察它的变化。例如
public class BaseController {
private final ObjectProperty<User> user;
// ...
//default constructor
public BaseController(){
user = new SimpleObjectProperty();
user.addListener((obs, oldUser, newUser) ->
userLabel.setText(newUser == null ? "" : newUser.getUsername()));
}
public ObjectProperty<User> userProperty() {
return user ;
}
public final User getUser() {
return userProperty().get();
}
public final void setUser(User user) {
userProperty().set(user);
}
// ...
}
和
public class HomePageController extends BaseController implements Initializable {
@FXML
private TableView<Goal> tbData ;
@FXML
public TableColumn<Goal, String> goalName;
@FXML
public TableColumn<Goal, String> goalDate;
@FXML
public TableColumn<Goal, String> goalStatus;
@FXML
public TableColumn<Goal, String> goalGroups;
public HomePageController() {
userProperty().addListener((obs, oldUser, newUser) -> {
if (newUser == null) {
tbData.setItems(FXCollections.observableArrayList());
} else {
tbData.setItems(getGoals());
}
});
}
// ...
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
goalName.setCellValueFactory(new PropertyValueFactory<>("goalName"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalDate"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalStatus"));
goalGroups.setCellValueFactory(new PropertyValueFactory<>("goalGroups"));
}
private ObservableList<Goal> getGoals(){
return FXCollections.observableList(user.getGoals());
}
}
通常这里 user 不是您需要观察的唯一值，因此它会被分解到某个模型中。例如，参见
我正在尝试在 JavaFX table 中显示对象列表，但在遍历要添加到 table 的对象时，我将 运行 保留在 JavaFX 异常中，确实任何人都知道可能是什么原因造成的，我已经尝试了 ObservableLists 的几种不同实现，但它们都看到产生相同的结果，我的结论是 class 或 .fxml 文件可能存在错误。提前致谢。
JavaFX:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.image.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.text.*?>
<BorderPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="HomePageController">
<left>
<AnchorPane prefHeight="400.0" prefWidth="200.0" style="-fx-background-color: #c7a4ff;" BorderPane.alignment="CENTER">
<children>
<Label fx:id="userLabel" alignment="TOP_CENTER" contentDisplay="CENTER" text="Hello <User>" textAlignment="CENTER" textFill="WHITE">
<font>
<Font name="Segoe UI Semilight" size="24.0" />
</font>
<padding>
<Insets bottom="10.0" left="25.0" right="25.0" top="10.0" />
</padding>
</Label>
<padding>
<Insets bottom="10.0" left="25.0" right="25.0" top="10.0" />
</padding>
</Label>
<Button layoutY="60.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Home" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="120.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Diet" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="180.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Workout" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="240.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="Groups" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
<Button layoutY="300.0" mnemonicParsing="false" onAction="#MenuSwitch" prefHeight="50.0" prefWidth="200.0" style="-fx-background-color: #aa80ff;" text="User Information" textFill="WHITE">
<font>
<Font size="14.0" />
</font>
</Button>
</children>
</AnchorPane>
</left>
<right>
<AnchorPane prefHeight="400.0" prefWidth="394.0" BorderPane.alignment="CENTER">
<children>
<Label alignment="TOP_CENTER" contentDisplay="CENTER" layoutX="148.0" text="Home" textAlignment="CENTER" textFill="#aa80ff">
<font>
<Font name="Segoe UI Semilight" size="24.0" />
</font>
<padding>
<Insets bottom="10.0" left="10.0" right="25.0" top="10.0" />
</padding>
</Label>
<Label alignment="TOP_CENTER" contentDisplay="CENTER" layoutX="14.0" layoutY="55.0" text="My Goals" textAlignment="CENTER" textFill="#aa80ff">
<font>
<Font name="Segoe UI Semilight" size="18.0" />
</font>
<padding>
<Insets bottom="10.0" left="10.0" right="25.0" top="10.0" />
</padding>
</Label>
<TableView fx:id="tbData" layoutX="14.0" layoutY="102.0" prefHeight="200.0" prefWidth="360.0" style="-fx-background-color: #ffffff;">
<columns>
<TableColumn fx:id="goalName" prefWidth="160.0" text="Name" />
<TableColumn fx:id="goalDate" prefWidth="50.0" text="Date" />
<TableColumn fx:id="goalStatus" prefWidth="75.0" text="Status" />
<TableColumn fx:id="goalGroups" prefWidth="10.0" text="Groups"/>
</columns>
</TableView>
</children>
</AnchorPane>
</right>
<bottom>
<AnchorPane prefHeight="50.0" prefWidth="600.0" style="-fx-background-color: #c7a4ff;" BorderPane.alignment="CENTER">
<children>
<ImageView fitHeight="30.0" fitWidth="30.0" layoutX="380.0" layoutY="10.0" pickOnBounds="true" preserveRatio="true">
<image>
<Image url="@img/add_box.png" />
</image>
</ImageView>
<Button graphicTextGap="0.0" layoutX="380.0" layoutY="10.0" mnemonicParsing="false" onAction="#openSelectGoalTypePage" opacity="0.0" prefHeight="30.0" prefWidth="30.0" />
<ImageView fitHeight="30.0" fitWidth="30.0" layoutX="300.0" layoutY="10.0" pickOnBounds="true" preserveRatio="true">
<image>
<Image url="@img/mode_edit.png" />
</image>
</ImageView>
<Button graphicTextGap="0.0" layoutX="300.0" layoutY="10.0" mnemonicParsing="false" onAction="#openEditGoalPage" opacity="0.0" prefHeight="30.0" prefWidth="30.0" />
<ImageView fitHeight="30.0" fitWidth="30.0" layoutX="460.0" layoutY="10.0" pickOnBounds="true" preserveRatio="true">
<image>
<Image url="@img/delete.png" />
</image>
</ImageView>
<Button graphicTextGap="0.0" layoutX="460.0" layoutY="10.0" mnemonicParsing="false" onAction="#removeTableItem" opacity="0.0" prefHeight="30.0" prefWidth="30.0" />
</children>
</AnchorPane>
</bottom>
</BorderPane>
控制者：
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.stage.Stage;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
public class HomePageController extends BaseController implements Initializable {
@FXML
private TableView<Goal> tbData = new TableView<>();
@FXML
public TableColumn<Goal, String> goalName;
@FXML
public TableColumn<Goal, String> goalDate;
@FXML
public TableColumn<Goal, String> goalStatus;
@FXML
public TableColumn<Goal, String> goalGroups;
/*@FXML
private Label userLabel;*/
//allow user to select a table item/row and delete it using the delete button
public void removeTableItem(){
}
public void openSelectGoalTypePage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("SelectGoalType.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openAddGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
//if user selects weight goal then open AddWeightGoal page
//else if user selects workout goal then open AddWorkoutGoal page
root = FXMLLoader.load(getClass().getResource("AddWeightGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openEditGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("EditGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
tbData = new TableView<>();
TableColumn<Goal, String> goalName = new TableColumn<>("GoalName");
goalName.setCellValueFactory(new PropertyValueFactory<>("goalName"));
TableColumn<Goal, String> goalDate = new TableColumn<>("GoalDate");
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalDate"));
TableColumn<Goal, String> goalStatus = new TableColumn<>("GoalStatus");
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalStatus"));
TableColumn<Goal, String> goalGroups = new TableColumn<>("GoalGroups");
goalGroups.setCellValueFactory(new PropertyValueFactory<>("goalGroups"));
tbData.getColumns().add(goalName);
tbData.getColumns().add(goalDate);
tbData.getColumns().add(goalStatus);
tbData.getColumns().add(goalGroups);
tbData.setItems(getGoals());
}
private ObservableList<Goal> getGoals(){
ObservableList<Goal> goals = FXCollections.observableArrayList();
for(int i = 0; i < user.getGoals().size(); i++){
goals.add(user.getGoals().get(i));
}
return goals;
}
}
目标Class：
import java.io.Serial;
import java.io.Serializable;
public class Goal implements Serializable {
@Serial
private static final long serialVersionUID = 1L;
public String getGoalName() {
return goalName;
}
public void setGoalName(String goalName) {
this.goalName = goalName;
}
public String getGoalDate() {
return goalDate;
}
public void setGoalDate(String goalDate) {
this.goalDate = goalDate;
}
public String getGoalStatus() {
return goalStatus;
}
public void setGoalStatus(String goalStatus) {
this.goalStatus = goalStatus;
}
public String getGoalGroups() {
return goalGroups;
}
public void setGoalGroups(String goalGroups) {
this.goalGroups = goalGroups;
}
public Goal(String goalName, String goalDate, String goalStatus, String goalGroups) {
this.goalName = goalName;
this.goalDate = goalDate;
this.goalStatus = goalStatus;
this.goalGroups = goalGroups;
}
String goalName;
String goalDate;
String goalStatus;
String goalGroups;
}
编辑：
我做了更多的调试，当我用一个 try-catch 块包围它时，它似乎从基本控制器指向我的用户对象为 null，尽管我相信我将它传递给了控制器持有用户对象的基本控制器，以及我用来传递用户对象的调用（在作为参数传递之前确认用户没有问题）。我似乎得到的唯一堆栈跟踪是加载程序，这是来自 try catch:java.lang.NullPointerException: Cannot invoke "User.getGoals()" because "this.user" is null :
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.stage.Stage;
import java.io.IOException;
public class BaseController {
User user;
Parent root;
Stage stage;
Scene scene;
@FXML
Label userLabel;
//default constructor
public BaseController(){
}
void setUser(User user){
this.user = user;
userLabel.setText(user.getUsername());
}
//connect to current user once logged in
/*
public BaseController(User user){
displayUsername(User);
}*/
//display current logged in user's first name
/*
private void displayUsername(User user){
userLabel.setText(user.firstName);
}*/
/**
* Menu Functions just in case
*/
// public void openHomePage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("HomePage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openDietPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("DietPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openWorkoutPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("WorkoutPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openGroupsPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("GroupsPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
//
// public void openUserPage(javafx.event.ActionEvent actionEvent) throws IOException {
// root = FXMLLoader.load(getClass().getResource("UserPage.fxml"));
// stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
// scene = new Scene(root);
// stage.setScene(scene);
// stage.show();
// }
public void MenuSwitch(javafx.event.ActionEvent actionEvent) throws IOException{
String text = ((Button)actionEvent.getSource()).getText();
String filename="";
switch(text){
case "Home":
filename="HomePage.fxml";break;
case "Diet":
filename="DietPage.fxml";break;
case "Workout":
filename="WorkoutPage.fxml";break;
case "Groups":
filename="GroupsPage.fxml";break;
case "User Information":
filename="UserPage.fxml";break;
case "Edit group":
filename="EditGroupPage.fxml"; break;
case "Create group":
filename="CreateGroupPage.fxml";break;
case "Add Diet Item":
filename="AddDietItemPage.fxml"; break;
case "EditWorkoutPage":
filename="EditWorkoutPage.fxml";break;
case "AddWorkoutPage":
filename="AddWorkoutPage.fxml";break;
case "EditUserPage":
filename="EditUserPage.fxml";break;
}
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource(filename));
Parent root = (Parent) fxmlLoader.load();
BaseController baseController = fxmlLoader.getController();
System.out.println(user);
baseController.setUser(user);
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
}
来自传递用户对象的前一个控制器：
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("HomePage.fxml"));
Parent root = (Parent) fxmlLoader.load();
HomePageController controller = fxmlLoader.getController();
controller.setUser(newUser);
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
谢谢！
编辑二： 完整堆栈跟踪：
java.lang.NullPointerException: Cannot invoke "User.getGoals()" because "this.user" is null
java.lang.NullPointerException: Cannot invoke "User.getGoals()" because "this.user" is null
at HomePageController.initialize(HomePageController.java:75)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2655)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:2517)
at UserLoginController.login(UserLoginController.java:108)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:76)
at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at javafx.base/com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:273)
at javafx.fxml/com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:83)
at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1857)
at javafx.fxml/javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1729)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Node.fireEvent(Node.java:8886)
at javafx.controls/javafx.scene.control.Button.fire(Button.java:203)
at javafx.controls/com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:208)
at javafx.controls/com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:247)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Scene$MouseHandler.process(Scene.java:3856)
at javafx.graphics/javafx.scene.Scene.processMouseEvent(Scene.java:1851)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2584)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:409)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:299)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent(GlassViewEventHandler.java:447)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:412)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:446)
at javafx.graphics/com.sun.glass.ui.View.handleMouseEvent(View.java:556)
at javafx.graphics/com.sun.glass.ui.View.notifyMouse(View.java:942)
at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication.lambda$runLoop(GtkApplication.java:277)
at java.base/java.lang.Thread.run(Thread.java:832)
java.sql.SQLException: The prepared statement has been finalized
控制器的initialize()方法在FXMLLoader.load()的执行过程中被调用，所以initialize()，因此getGoals()在之前被调用[=40] =] 你打电话给 setUser(...)。因此 user 在您尝试调用 user.getGoals().
要在您设置的结构中修复此问题，您需要在调用 setUser(...) 时填充 table 列表。您可以在子类中使用重写的 setUser(...) 方法来做到这一点。
另请注意，初始化 @FXML 注释字段总是错误的（因为它们由 FXMLLoader 初始化为 FXML 文件中定义的元素）。所以你的控制器应该看起来像这样：
public class HomePageController extends BaseController implements Initializable {
@FXML
private TableView<Goal> tbData ;
@FXML
public TableColumn<Goal, String> goalName;
@FXML
public TableColumn<Goal, String> goalDate;
@FXML
public TableColumn<Goal, String> goalStatus;
@FXML
public TableColumn<Goal, String> goalGroups;
/*@FXML
private Label userLabel;*/
//allow user to select a table item/row and delete it using the delete button
public void removeTableItem(){
}
public void openSelectGoalTypePage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("SelectGoalType.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openAddGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
//if user selects weight goal then open AddWeightGoal page
//else if user selects workout goal then open AddWorkoutGoal page
root = FXMLLoader.load(getClass().getResource("AddWeightGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public void openEditGoalPage(javafx.event.ActionEvent actionEvent) throws IOException {
root = FXMLLoader.load(getClass().getResource("EditGoal.fxml"));
stage = (Stage)((Node)actionEvent.getSource()).getScene().getWindow();
scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
goalName.setCellValueFactory(new PropertyValueFactory<>("goalName"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalDate"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalStatus"));
goalGroups.setCellValueFactory(new PropertyValueFactory<>("goalGroups"));
}
@Override
void setUser(User user){
super.setUser(user);
tbData.setItems(getGoals());
}
private ObservableList<Goal> getGoals(){
return FXCollections.observableList(user.getGoals());
}
}
一种更标准的方法是使用 MVC 类型的设计，其中用户由 ObjectProperty<User> 表示，您可以观察它的变化。例如
public class BaseController {
private final ObjectProperty<User> user;
// ...
//default constructor
public BaseController(){
user = new SimpleObjectProperty();
user.addListener((obs, oldUser, newUser) ->
userLabel.setText(newUser == null ? "" : newUser.getUsername()));
}
public ObjectProperty<User> userProperty() {
return user ;
}
public final User getUser() {
return userProperty().get();
}
public final void setUser(User user) {
userProperty().set(user);
}
// ...
}
和
public class HomePageController extends BaseController implements Initializable {
@FXML
private TableView<Goal> tbData ;
@FXML
public TableColumn<Goal, String> goalName;
@FXML
public TableColumn<Goal, String> goalDate;
@FXML
public TableColumn<Goal, String> goalStatus;
@FXML
public TableColumn<Goal, String> goalGroups;
public HomePageController() {
userProperty().addListener((obs, oldUser, newUser) -> {
if (newUser == null) {
tbData.setItems(FXCollections.observableArrayList());
} else {
tbData.setItems(getGoals());
}
});
}
// ...
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
goalName.setCellValueFactory(new PropertyValueFactory<>("goalName"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalDate"));
goalDate.setCellValueFactory(new PropertyValueFactory<>("goalStatus"));
goalGroups.setCellValueFactory(new PropertyValueFactory<>("goalGroups"));
}
private ObservableList<Goal> getGoals(){
return FXCollections.observableList(user.getGoals());
}
}
通常这里 user 不是您需要观察的唯一值，因此它会被分解到某个模型中。例如，参见