从 TableView 中的可编辑列动态填充 ChoiceBox

Question

基本上问题标题说明了一切。我在表格视图中有一个字符串列（称为type）和一个对应的数字列（称为size），每一行代表一个对象CargoItem，它有两个属性type和size。 两列都是可编辑的。 TableView 与CargoItem 的对应可观察列表相关联，称为cargoList。

ChoiceBox 最初设置为可观察列表。我有一个附加到 ChoiceBox 的侦听器，因此它可以使用相应的 size 属性更新 TextField。这可以正常工作：如果您在 size 列的单元格中键入新值，则 TextField 中的相应值将更新（一旦选择了 ChoiceBox 项）。

目前，如果我编辑 type 列中的单元格，ChoiceBox 中的项目将不会更新。我有一个诊断按钮，它将验证可观察列表是否正确更新。我想我需要在类型列的单元格中放置一个监听器，但不确定如何。

以下是一个最小的工作示例，包含 4 个文件：Table_test02.fxml、CargoItem.java、ControllerTest.java 和 TestApp.java

Table_test02.fxml：

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

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

<AnchorPane fx:id="root" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="252.0" prefWidth="232.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="so_question01.ControllerTest">
   <children>
      <TableView fx:id="cargoTable" editable="true" layoutX="9.0" layoutY="30.0" prefHeight="107.0" prefWidth="213.0">
         <columnResizePolicy>
            <TableView fx:constant="CONSTRAINED_RESIZE_POLICY" />
         </columnResizePolicy>
         <columns>
            <TableColumn fx:id="cargoTableTypeCol" maxWidth="130.0" minWidth="60.0" prefWidth="75.0" sortable="false" text="Type" />
            <TableColumn fx:id="cargoTableSizeCol" maxWidth="118.0" minWidth="60.0" prefWidth="67.0" sortable="false" text="Size" />
         </columns>
      </TableView>
      <Label layoutX="10.0" layoutY="11.0" text="Cargo">
         <font>
            <Font name="System Bold" size="12.0" />
         </font>
      </Label>
      <ChoiceBox fx:id="externalChoiceBox" layoutX="9.0" layoutY="162.0" prefHeight="25.0" prefWidth="99.0" />
      <TextField fx:id="externalTextField" layoutX="123.0" layoutY="162.0" prefHeight="25.0" prefWidth="99.0" />
      <Button fx:id="diagnosticButton" layoutX="83.0" layoutY="210.0" mnemonicParsing="false" text="Diagnostic" textFill="#862828">
         <font>
            <Font name="Arial Black" size="11.0" />
         </font>
      </Button>
      <Label layoutX="10.0" layoutY="143.0" text="Type">
         <font>
            <Font name="System Bold" size="12.0" />
         </font>
      </Label>
      <Label layoutX="123.0" layoutY="144.0" text="Size">
         <font>
            <Font name="System Bold" size="12.0" />
         </font>
      </Label>
   </children>
</AnchorPane>

CargoItem.java：

package so_question01;

import javafx.beans.property.*;

public class CargoItem {

   private final StringProperty type;
   private final FloatProperty size;

   public CargoItem() {
      this.type = new SimpleStringProperty("");
      this.size = new SimpleFloatProperty(0f);
   }

   public CargoItem(String type, float size) {
      this.type = new SimpleStringProperty(type);
      this.size = new SimpleFloatProperty(size);
   }

   public void setType(String type) {
      this.type.set(type);
   }

   public void setSize(float size) {
      this.size.set(size);
   }

   public String getType() {
      if (!(type.get().equals("") || type.get() == null )) {
         return type.get();
      }
      return "";
   }

   public float getSize() {
      return size.get();
   }

   public StringProperty typeProperty() {
      return type;
   }

   public FloatProperty sizeProperty() {
      return size;
   }

   public void clear() {
      this.type.set("");
      this.size.set(0);
   }

   @Override
   public String toString() {  
      return type.get();     
   }

   public String display() {
      return "\nCARGO ITEM:"
              + "\n\ttype: " + type.get()
              + "\n\tsize: " + size.get();
   }
}

ControllerTest.java：

package so_question01;

import java.text.DecimalFormat;
import javafx.collections.ListChangeListener.*;
import javafx.collections.ObservableList;
import javafx.collections.FXCollections;
import javafx.collections.*;
import javafx.fxml.FXML;
import javafx.scene.control.Button;
import javafx.scene.control.ChoiceBox;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.control.cell.*;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.beans.value.ObservableValue;
import javafx.util.StringConverter;
import javafx.beans.value.*;

public class ControllerTest {

    ObservableList<CargoItem> cargoList = FXCollections.observableArrayList();
   private TestApp mainApp;   // Reference to the main application.

   @FXML private ChoiceBox externalChoiceBox;
   @FXML private TextField externalTextField;
   @FXML private Button diagnosticButton;
    @FXML   private TableView<CargoItem> cargoTable;
    @FXML   private TableColumn<CargoItem, Float> cargoTableSizeCol;
    @FXML   private TableColumn<CargoItem, String> cargoTableTypeCol;

    public ControllerTest() {  }

    @FXML
    private void initialize() {

      //*****DIAGNOSTIC ONLY*******************//
      diagnosticButton.setOnAction(e->{
         for(CargoItem c: cargoList){
            System.out.print(c.display());
         }
      });
      //does not work when changes made via table editing, but may be useful when new list loaded from file?
      cargoList.addListener(new ListChangeListener< CargoItem>(){
         public void onChanged(Change<? extends CargoItem> c){
             // Do your changes here
            System.out.println(c.getList()); 
         }});

      //**** test choicebox***//
      StringConverter cargoItemConverter= new CargoItemStringConverter();
      externalChoiceBox.setConverter(cargoItemConverter);

      //***************** CARGO TABLE  **************//
      cargoTable.setEditable(true);
      // Initialize the cargo table with the 2 columns.
        cargoTableTypeCol.setCellFactory(TextFieldTableCell.forTableColumn());
        cargoTableTypeCol.setCellValueFactory(new PropertyValueFactory<>("type"));

        cargoTableSizeCol.setCellFactory(TextFieldTableCell.forTableColumn(new FloatIntegerStringConverter()));
        cargoTableSizeCol.setCellValueFactory(new PropertyValueFactory<>("size"));
    }

    /**
     * Is called by the main application to give a reference back to itself.
     *
     * @param mainApp
     */
    public void setMainApp(TestApp mainApp) {
        this.mainApp = mainApp;   
      cargoList.setAll(mainApp.getCargoData());

        // Add observable list data to the table
        cargoTable.setItems(cargoList);
        cargoTable.getSelectionModel().setCellSelectionEnabled(true);

      externalChoiceBox.setItems(cargoList); 
      //adds listener to choicebox selection, so size is rendered to text field
      externalChoiceBox.getSelectionModel().selectedItemProperty().addListener(
         new ChangeListener<CargoItem>() {
             @Override public void changed(ObservableValue<? extends CargoItem> observableValue, CargoItem oldChoice, CargoItem newChoice) {
                externalTextField.setText(new FloatIntegerStringConverter().toString(newChoice.getSize()));
            }
         });
    }
}

//*******string converter classes, nothing to see here************//
class CargoItemStringConverter extends StringConverter<CargoItem>{
   @Override
   public String toString(CargoItem c){
      return c.toString();         
   }
   @Override
   public CargoItem fromString(String type){
      return null;
   }
}

class FloatIntegerStringConverter extends StringConverter<Float> 
{
    DecimalFormat decimalFormat = new DecimalFormat("##,###,##0");
    private Float returnVal;

   @Override
   public Float fromString(String value) {       
      if (value == null) {
         return null;
      }
      value = value.trim();
      String digits = value.replaceAll("[^0-9.]", ""); //gets rid of non-numerics

      if (digits.length() < 1) {
         return null;
      }
      try{  //avoids exception by converting invalid strings to zero (which should just be redundant due to regexp above)
      returnVal=  Float.valueOf(Math.round(Float.valueOf(digits)));//have to do this so the float value coresponds to the rounded value in table
      } catch(NumberFormatException e) { returnVal= Float.valueOf(0); }
      return  returnVal;             
    }

    @Override 
    public String toString(Float value) {
      if (value == null) {  // If the specified value is null, return a zero-length String
         return "";
      }
      return decimalFormat.format(value)+" MT"; //truncated integer representation, unit metric tonnes
   }
}

TestApp.java：

package so_question01;

import java.io.*;
import javafx.fxml.FXMLLoader;
import javafx.scene.layout.*;
import javafx.collections.ObservableList;
import javafx.collections.FXCollections;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class TestApp extends Application {

    private Stage primaryStage;
   private  ObservableList<CargoItem> cargoData = FXCollections.observableArrayList(); 

   public TestApp() {
      // create some sample data
        CargoItem cargoInstance0 = new CargoItem("Toxic waste", 5000f);
        CargoItem cargoInstance1 = new CargoItem("Cement", 10000f);
        CargoItem cargoInstance2 = new CargoItem("Wheat", 20000f);
        cargoData.add(cargoInstance0);
        cargoData.add(cargoInstance1);
        cargoData.add(cargoInstance2);
   }

    /**
     * Returns the data as observable lists of objects. 
     * @return
     */
    public ObservableList<CargoItem> getCargoData() {return cargoData; }   //called in the controller

   @Override
   public void start(Stage primaryStage) { 
        this.primaryStage = primaryStage;
      this.primaryStage.setTitle("**** TEST ****");   
      show();
    }

      /**
     * Initializes the root layout.
     */
    public void show() {
        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(TestApp.class.getResource("Table_test02.fxml"));
            AnchorPane root = (AnchorPane) loader.load();

            // Give the controller access to the main app.
            ControllerTest controller = loader.getController();
            controller.setMainApp(this);

            // Show the scene containing the root layout.
            Scene scene = new Scene(root);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (IOException e) { System.out.println(e);}
    } 

   /**
     * Returns the main stage.
     * @return
     */
    public Stage getPrimaryStage() {
        return primaryStage;
    }

    public static void main(String[] args) { 
        Application.launch(TestApp.class, (java.lang.String[])null);
    }   
}

Answer 1

假设我正确理解了这个问题，您需要使用 extractor 初始化您的 cargoList：

ObservableList<CargoItem> cargoList = FXCollections.observableArrayList(cargo -> 
    new Observable[]{cargo.typeProperty(), cargo.sizeProperty()});

ChoiceBox 一直无法很好地处理对其基础列表的更新通知；我不确定最新版本是否已修复所有问题。您可能要考虑改用ComboBox。

更新

如果您需要使用ChoiceBox，解决方法可能不是将项目直接设置为cargoList，而是在cargoList 更改时更新项目。您可以通过在setMainApp(...) 中进行以下更改来做到这一点：

//  externalChoiceBox.setItems(cargoList); 
    externalChoiceBox.getItems().setAll(cargoList);

并在您的列表更改侦听器中添加以下内容：

  cargoList.addListener(new ListChangeListener< CargoItem>(){
     public void onChanged(Change<? extends CargoItem> c){
         // Do your changes here
        System.out.println(c.getList()); 
        externalChoiceBox.getItems().setAll(cargoList);
     }});