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我在我正在使用的主屏幕上有兩個表格。從文本字段中提取空數據。表已填充，但無法檢索對象。 Java/JavaFX
零件表和產品表。產品由零件組成。零件表（搜索，選擇等）的表功能都可以正常工作。當一個新產品被創建並添加到表中時，它似乎就在那裏。但是，當我試圖檢索數據進行修改時，通過用數據初始化產品字段，我得到了一個NPE。當使用與Part表相同的搜索功能時，搜索功能找不到該零件。
列出的是有問題的文件...
MainScreenController.java
/**
* Sample Skeleton for 'MainScreen.fxml' Controller Class
*/
package jbernsd_IMS.View;
import javafx.application.Platform;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.collections.transformation.SortedList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Alert;
import javafx.scene.control.Button;
import javafx.scene.control.ButtonType;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import jbernsd_IMS.MainApp;
import jbernsd_IMS.Model.Inventory;
import jbernsd_IMS.Model.Part;
import jbernsd_IMS.Model.Product;
public class MainScreenController {
// Table and column declarations for Part table.
// fx:id partTableMain
@FXML
private TableView<Part> partTableMain;
// fx:ids are respective...ie partIdColumnMain, partInvColumnMain, etc.
@FXML
private TableColumn<Part, Integer> partIdColumnMain, partInvColumnMain;
// fx:id partNameColumnMain;
@FXML
private TableColumn<Part, String> partNameColumnMain;
// fx:id partCostColumnMain
@FXML
private TableColumn<Part, Double> partCostColumnMain;
// Table and column declarations for Product table.
// fx:id productTableMain
@FXML
private TableView<Product> productTableMain;
// fx:ids are respective...ie productIdColumnMain, productInvColumnMain, etc.
@FXML
private TableColumn<Product, Integer> productIdColumnMain, productInvColumnMain;
// fx:id productNameColumnMain
@FXML
private TableColumn<Product, String> productNameColumnMain;
// fx:id productCostColumnMain
@FXML
private TableColumn<Product, Double> productCostColumnMain;
// fx:ids are respective...ie addPartButtonMain, modPartButtonMain, etc.
@FXML
private Button addPartButtonMain, modPartButtonMain, delPartButtonMain, searchPartButtonMain,
addProductButtonMain, modProductButtonMain, delProductButtonMain, searchProductButtonMain,
exitButton;
// fx:ids are respective...ie searchPartFieldMain, searchProductFieldMain, etc.
@FXML
private TextField searchPartFieldMain, searchProductFieldMain;
private boolean okClicked = false;
// Reference to the main application...
private MainApp mainApp;
/**
* The MainScreenController (MSC) no-argument Constructor
* The constructor is called before the initialize() method.
*/
public MainScreenController() {
}
/**
* Initializes the controller class. This method is automatically called
* after the fxml file has been loaded.
*/
@FXML
private void initialize() {
partIdColumnMain.setCellValueFactory(cellData -> cellData.getValue().partIdProperty().asObject());
partNameColumnMain.setCellValueFactory(cellData -> cellData.getValue().partNameProperty());
partInvColumnMain.setCellValueFactory(cellData -> cellData.getValue().partInvProperty().asObject());
partCostColumnMain.setCellValueFactory(cellData -> cellData.getValue().partCostProperty().asObject());
productIdColumnMain.setCellValueFactory(cellData -> cellData.getValue().productIdProperty().asObject());
productNameColumnMain.setCellValueFactory(cellData -> cellData.getValue().productNameProperty());
productInvColumnMain.setCellValueFactory(cellData -> cellData.getValue().productInvProperty().asObject());
productCostColumnMain.setCellValueFactory(cellData -> cellData.getValue().productCostProperty().asObject());
}
// setText(String.format("%0.2f", value.doubleValue()));
/**
* Is called by the main application to give reference to itself.
*
* @param mainApp
*/
public void setMainApp(MainApp mainApp) {
this.mainApp = mainApp;
// Add observable list data to the table
partTableMain.setItems(Inventory.getAllParts());
productTableMain.setItems(Inventory.getProducts());
}
// onAction="#handleNewPart"
@FXML
private void handleNewPart() {
okClicked = mainApp.showAddPartScreen();
}
// onAction="#handleNewProduct"
@FXML
private void handleNewProduct() {
okClicked = mainApp.showAddProductScreen();
}
// onAction="#handleModPart"
@FXML
private void handleModPart(ActionEvent e) {
Inventory.selectedPart = partTableMain.getSelectionModel().getSelectedItem();
Part selectedPart = Inventory.selectedPart;
if(selectedPart != null) {
Alert alert = new Alert(Alert.AlertType.CONFIRMATION);
alert.setTitle("Selection Confirmation");
alert.setHeaderText("Please confirm the part you selected...");
alert.setContentText("You have selected: \n\n"
+ "Part ID: \t\t" + selectedPart.partIdProperty().getValue() + "\n"
+ "Part Name: \t" + selectedPart.partNameProperty().getValueSafe() + "\n\n");
alert.showAndWait()
.filter(response -> response == ButtonType.OK)
.ifPresent(response -> mainApp.showModPartScreen());
okClicked = true;
} else { // //
// Nothing selected...
Alert alert = new Alert(Alert.AlertType.WARNING);
alert.setTitle("No selection");
alert.setHeaderText("No part selected");
alert.setContentText("Please select a part in the table.");
alert.showAndWait()
.filter(response -> response == ButtonType.OK)
.ifPresent(response -> alert.close());
okClicked = false;
}
}
// onAction="#handleModProduct"
@FXML
private void handleModProduct(ActionEvent e) {
// productTableMain.setOnMouseClicked((MouseEvent event) -> {
// if(event.getButton().equals(MouseButton.PRIMARY)) {}
// });
Inventory.selectedProduct = productTableMain.getSelectionModel().getSelectedItem();
Product selectedProduct = Inventory.selectedProduct;
if(selectedProduct != null) {
Alert alert = new Alert(Alert.AlertType.CONFIRMATION);
alert.setTitle("Selection Confirmation");
alert.setHeaderText("Please confirm the product you selected...");
alert.setContentText("You have selected: \n\n"
+ "Product ID: \t\t" + selectedProduct.productIdProperty().getValue() + "\n"
+ "Product Name: \t" + selectedProduct.productNameProperty().getValueSafe() + "\n\n");
alert.showAndWait()
.filter(response -> response == ButtonType.OK)
.ifPresent(response -> mainApp.showModProductScreen());
okClicked = true;
} else { // //
// Nothing selected...
Alert alert = new Alert(Alert.AlertType.WARNING);
alert.setTitle("No selection");
alert.setHeaderText("No products selected");
alert.setContentText("Please select a product in the table.");
alert.showAndWait()
.filter(response -> response == ButtonType.OK)
.ifPresent(response -> alert.close());
okClicked = false;
}
}
// fx:id foundMe
@FXML
private void foundMe() {
Alert alert = new Alert(Alert.AlertType.INFORMATION);
alert.setTitle("Easter Egg!! (Illegal after 9/11)");
alert.setHeaderText("Congratulations!!!");
alert.setContentText("Congratulations!! You found my Easter Egg!!! :) ");
alert.showAndWait();
}
@FXML
private void handleClose(ActionEvent e) {
Platform.exit();
}
/**
* Called when the user clicks on the delete button.
*/
@FXML
private void handleDelete(ActionEvent e) {
Part selectedPart = partTableMain.getSelectionModel().getSelectedItem();
if(selectedPart != null) {
// Confirm deletion
Alert alert = new Alert(Alert.AlertType.CONFIRMATION);
alert.setTitle("Confirm Deletion");
alert.setHeaderText("Deleting...");
alert.setContentText("Are you sure you want to delete the part? \n\n"
+ "Part ID: \t\t" + selectedPart.partIdProperty().getValue() + "\n"
+ "Part Name: \t" + selectedPart.partNameProperty().getValueSafe());
alert.showAndWait()
.filter(response -> response == ButtonType.OK)
.ifPresent(response -> Inventory.getAllParts().remove(selectedPart));
// Update partTableMain
partTableMain.setItems(Inventory.getAllParts());
} else {
// Nothing selected...
Alert alert = new Alert(Alert.AlertType.WARNING);
alert.setTitle("No selection");
alert.setHeaderText("No part selected");
alert.setContentText("Please select a part in the table.");
alert.showAndWait();
}
}
@FXML
private void handleDeleteProd(ActionEvent e) {
Product selectedProduct = productTableMain.getSelectionModel().getSelectedItem();
if(selectedProduct != null) {
// Confirm deletion
Alert alert = new Alert(Alert.AlertType.CONFIRMATION);
alert.setTitle("Confirm Deletion");
alert.setHeaderText("Deleting...");
alert.setContentText("Are you sure you want to delete the product? \n\n"
+ "Part ID: \t\t" + selectedProduct.productIdProperty().getValue() + "\n"
+ "Part Name: \t" + selectedProduct.productNameProperty().getValueSafe()); //
alert.showAndWait()
.filter(response -> response == ButtonType.OK)
.ifPresent(response -> Inventory.getProducts().remove(selectedProduct));
// Update partTableMain
productTableMain.setItems(Inventory.getProducts());
} else { // //
// Nothing selected...
Alert alert = new Alert(Alert.AlertType.WARNING);
alert.setTitle("No selection");
alert.setHeaderText("No product selected");
alert.setContentText("Please select a product in the table.");
alert.showAndWait();
}
}
@FXML
private void searchPartTable() {
String searchItem = searchPartFieldMain.getText();
if(isSearchInputValid(searchItem)) {
FilteredList<Part> searchPartResults = searchParts(searchItem);
SortedList<Part> sortedParts = new SortedList<>(searchPartResults);
sortedParts.comparatorProperty().bind(partTableMain.comparatorProperty());
partTableMain.setItems(sortedParts);
searchPartFieldMain.clear();
}
}
private FilteredList<Part> searchParts (String s) {
return Inventory.getAllParts().filtered(p -> p.getPartName().toLowerCase().contains(s.toLowerCase()));
}
@FXML
void searchProductTable() {
String searchItem = searchProductFieldMain.getText();
if(isSearchInputValid(searchItem)) {
FilteredList<Product> searchProductResults = searchProducts(searchItem);
SortedList<Product> sortedProducts = new SortedList<>(searchProductResults);
sortedProducts.comparatorProperty().bind(productTableMain.comparatorProperty());
productTableMain.setItems(sortedProducts);
}
}
public FilteredList<Product> searchProducts (String s) {
return Inventory.getProducts().filtered(p -> p.getProductName().contains(s.substring(0, 1).toUpperCase()
+ s.substring(1).toLowerCase()));
}
public boolean isSearchInputValid(String searchItem) {
ObservableList<Part> list = FXCollections.observableArrayList(Inventory.getAllParts());
String errorMessage = "";
String partName;
if(Inventory.getAllParts().isEmpty()) {
errorMessage += "Inv: \t\t There are no parts in inventory to search. \n\n";
}
if(!searchItem.equalsIgnoreCase("")) {
int count = 0;
for(Part p:Inventory.getAllParts()) {
String name = p.partNameProperty().getValueSafe();
if(!searchItem.equalsIgnoreCase(name) || searchItem.equals(null)) {
count++;
if(count == Inventory.getAllParts().size()) {
errorMessage += "Inv: \t\t The search item, " + "\"" + searchItem + "\"" + " does not match \n"
+ "\t\t any known items in the inventory. \n\n"
+ "\t\t The item cannot be found, or it does not exist. \n";
}
}
}
}
if(errorMessage.length() == 0) {
return true;
} else {
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setTitle("Error");
alert.setHeaderText("Data Error Exists");
alert.setContentText(errorMessage);
alert.showAndWait();
return false;
}
}
}
MainScreen.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TableColumn?>
<?import javafx.scene.control.TableView?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.control.cell.PropertyValueFactory?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.shape.Rectangle?>
<?import javafx.scene.text.Font?>
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="800.0" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1" fx:controller="jbernsd_IMS.View.MainScreenController">
<children>
<Rectangle fx:id="borderPartsMAIN" arcHeight="10.0" arcWidth="10.0" fill="TRANSPARENT" height="280.0" layoutX="25.0" layoutY="56.0" stroke="#979797" strokeLineCap="BUTT" strokeLineJoin="ROUND" strokeType="OUTSIDE" strokeWidth="2.0" width="366.0" />
<Label fx:id="labelInvMgmtSysMAIN" layoutX="18.0" layoutY="15.0" text=" Inventory Management System">
<font>
<Font name="Calibri Italic" size="24.0" />
</font>
</Label>
<!-- Parts section begins here -->
<TableView fx:id="partTableMain" layoutX="35.0" layoutY="95.0" prefHeight="188.0" prefWidth="344.0">
<columns>
<TableColumn fx:id="partIdColumnMain" prefWidth="54.0" text="Part ID">
<cellValueFactory>
<PropertyValueFactory property="partID" />
</cellValueFactory>
</TableColumn>
<TableColumn fx:id="partNameColumnMain" prefWidth="71.0" text="Part Name">
<cellValueFactory>
<PropertyValueFactory property="partName" />
</cellValueFactory>
</TableColumn>
<TableColumn fx:id="partInvColumnMain" minWidth="0.0" prefWidth="97.0" text="Inventory Level">
<cellValueFactory>
<PropertyValueFactory property="partInv" />
</cellValueFactory>
</TableColumn>
<TableColumn fx:id="partCostColumnMain" prefWidth="121.0" text="Price/Cost per Unit">
<cellValueFactory>
<PropertyValueFactory property="partCost" />
</cellValueFactory>
</TableColumn>
</columns>
</TableView>
<!-- Parts sections ends here -->
<Label fx:id="labelPartsPrtsMAIN" layoutX="36.0" layoutY="58.0" text="Parts">
<font>
<Font name="Calibri Italic" size="24.0" />
</font>
</Label>
<Button fx:id="searchPartButtonMain" layoutX="179.0" layoutY="63.0" mnemonicParsing="false" onAction="#searchPartTable" text="Search">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
<TextField fx:id="searchPartFieldMain" layoutX="241.0" layoutY="63.0" prefHeight="25.0" prefWidth="136.0" />
<HBox layoutX="169.0" layoutY="294.0" spacing="15.0">
<children>
<Button fx:id="addPartButtonMain" mnemonicParsing="false" onAction="#handleNewPart" prefHeight="30.0" prefWidth="60.0" text="Add">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
<Button fx:id="modPartButtonMain" mnemonicParsing="false" onAction="#handleModPart" prefHeight="30.0" prefWidth="60.0" text="Modify">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
<Button fx:id="delPartButtonMain" mnemonicParsing="false" onAction="#handleDelete" prefHeight="30.0" prefWidth="60.0" text="Delete">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
</children>
</HBox>
<!-- Parts section ends here -->
<!-- Products section begins here -->
<Rectangle fx:id="borderProdsMAIN" arcHeight="10.0" arcWidth="10.0" fill="TRANSPARENT" height="280.0" layoutX="410.0" layoutY="56.0" stroke="#979797" strokeLineCap="BUTT" strokeLineJoin="ROUND" strokeType="OUTSIDE" strokeWidth="2.0" width="370.0" />
<TableView fx:id="productTableMain" layoutX="420.0" layoutY="95.0" prefHeight="188.0" prefWidth="344.0">
<columns>
<TableColumn fx:id="productIdColumnMain" prefWidth="54.0" text="Prod ID" />
<TableColumn fx:id="productNameColumnMain" prefWidth="71.0" text="Prod Name" />
<TableColumn fx:id="productInvColumnMain" minWidth="0.0" prefWidth="97.0" text="Inventory Level" />
<TableColumn fx:id="productCostColumnMain" prefWidth="121.0" text="Price/Cost per Unit" />
</columns>
</TableView>
<Label fx:id="labelProdsMAIN" layoutX="421.0" layoutY="58.0" text="Products">
<font>
<Font name="Calibri Italic" size="24.0" />
</font>
</Label>
<Button fx:id="searchProductButtonMain" layoutX="564.0" layoutY="63.0" mnemonicParsing="false" onAction="#searchProductTable" text="Search">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
<TextField fx:id="searchProductFieldMain" layoutX="626.0" layoutY="63.0" prefHeight="25.0" prefWidth="136.0" />
<HBox layoutX="554.0" layoutY="294.0" spacing="15.0">
<children>
<Button fx:id="addProductButtonMain" mnemonicParsing="false" onAction="#handleNewProduct" prefHeight="30.0" prefWidth="60.0" text="Add">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
<Button fx:id="modProductButtonMain" mnemonicParsing="false" onAction="#handleModProduct" prefHeight="30.0" prefWidth="60.0" text="Modify">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
<Button fx:id="delProductButtonMain" mnemonicParsing="false" onAction="#handleDeleteProd" prefHeight="30.0" prefWidth="60.0" text="Delete">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
</children>
</HBox>
<Button fx:id="foundMe" layoutX="309.0" layoutY="109.0" mnemonicParsing="false" onAction="#foundMe" prefHeight="2.0" prefWidth="2.0" textFill="TRANSPARENT" AnchorPane.bottomAnchor="288.0" AnchorPane.leftAnchor="309.0" AnchorPane.rightAnchor="489.0" AnchorPane.topAnchor="109.0">
<font>
<Font size="2.0" />
</font>
</Button>
<Button fx:id="exitButton" layoutX="370.0" layoutY="356.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#handleClose" prefHeight="30.0" prefWidth="60.0" text="Exit">
<font>
<Font name="Calibri Italic" size="12.0" />
</font></Button>
<!-- Products section ends here -->
</children>
</AnchorPane>
代碼中的哪個位置可以獲得NPE？ –
這是在不同的代碼部分，我無法發佈。這是我第一次發表SO/SE的文章，它說我已經超過了我的人物數量。我還有兩個其他文件可以發佈。 我的修復程序是在我的.fxml文件中，我沒有fx：id條目，用於我試圖填充的字段。菜鳥犯的菜鳥錯誤。所以一旦我糾正了fx：id條目來匹配我的字段名稱，我沒事。 我非常想發佈我的其他代碼，這樣人們可能會失去我的錯誤，但不知道如何處理字符計數通知！ –