设置自定义javafx组合框的值

编辑：我包含了一些给我带来错误的示例文件 我正在尝试实现一个组合框，它根据击键来过滤项目，遵循来自的配方。我想列出世界上的国家

我正在使用FilterComboBox.fxml

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

<?import java.lang.*?>
<?import javafx.collections.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import persondetails2.controller.*?>

<fx:root type="javafx.scene.control.ComboBox" fx:id="countries" 
         xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" 
         fx:controller="persondetails2.controller.FilterComboBox">
        <items>
          <FXCollections fx:factory="observableArrayList">
            <String fx:value="Austria" />
            <String fx:value="Denmark" />
            <String fx:value="France" />
            <String fx:value="Germany" />
            <String fx:value="Italy" />
            <String fx:value="Portugal" />
            <String fx:value="Spain" />
          </FXCollections>
        </items>
</fx:root>

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


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


<AnchorPane xmlns:fx="http://javafx.com/fxml/1" id="AnchorPane" prefHeight="200" prefWidth="320" fx:controller="persondetails2.controller.PersonDetailsController">
  <ScrollPane id="personalData" fx:id="personaldata" fitToHeight="false" focusTraversable="false" maxHeight="-Infinity" prefHeight="-1.0" prefViewportHeight="1440.0" prefWidth="569.0" AnchorPane.bottomAnchor="2.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="-2.0">
    <content>
      <AnchorPane id="Content" focusTraversable="false" maxWidth="-1.0" minHeight="0.0" minWidth="0.0" prefHeight="-1.0" prefWidth="600.0">
        <children>
          <VBox focusTraversable="false" prefHeight="-1.0" prefWidth="-1.0" spacing="2.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
            <children>
              <Label prefHeight="21.0001220703125" text="Personal Details">
                <font>
                  <Font name="System Bold" size="14.0" fx:id="x1" />
                </font>
              </Label>

              <GridPane id="GridPane" focusTraversable="false" hgap="3.0" prefWidth="354.0" vgap="4.0">
                <children>
                  <Label text="Name:" GridPane.columnIndex="0" GridPane.rowIndex="0">
                    <labelFor>
                      <TextField fx:id="name" prefWidth="200.0" GridPane.columnIndex="1" GridPane.rowIndex="0" />
                    </labelFor>
                  </Label>
                  <fx:reference source="name" />
                  <Label text="Surname:" GridPane.columnIndex="0" GridPane.rowIndex="1" />
                  <TextField fx:id="surname" prefWidth="200.0" GridPane.columnIndex="1" GridPane.rowIndex="1" />
                  <Label text="Country:" GridPane.columnIndex="0" GridPane.rowIndex="2"  />
                  <fx:include source="FilterComboBox.fxml" GridPane.columnIndex="1" GridPane.rowIndex="2" />
                </children>
              </GridPane>
            </children>
            <padding>
              <Insets bottom="10.0" left="10.0" right="10.0" top="10.0" />
            </padding>
          </VBox>
        </children>
        <padding>
          <Insets left="5.0" right="5.0" />
        </padding>
      </AnchorPane>
    </content>
  </ScrollPane>
</AnchorPane>

这个配置现在为我提供了一个

java.lang.InstantiationException:persondetails2.controller.FilterComboBox

。我想读取控制器初始化中的数据，然后能够设置文本字段中的值以及组合框中的所选值

---

关于如何继续，有什么想法吗？

既然您正在FXML文件中为combobox设置项，我将FilterComboBox构造函数重构为no参数，并添加了加载FXML文件的代码：

public class FilterComboBox<T> extends ComboBox<T> {

    private final ObservableList<T> items;
    private final ObservableList<T> filter;
    private String s;
    private Object selection;

    private class KeyHandler implements EventHandler<KeyEvent> {

        private SingleSelectionModel<T> sm;

        public KeyHandler() {
            sm = getSelectionModel();
            s = "";
            System.err.println("Initialized keyhandler");
        }

        @Override
        public void handle(KeyEvent event) {
            filter.clear();
            // handle non alphanumeric keys like backspace, delete etc
            if (event.getCode() == KeyCode.BACK_SPACE && s.length() > 0) {
                s = s.substring(0, s.length() - 1);
            } else {
                s += event.getText();
            }

            if (s.length() == 0) {
                setItems(items);
                sm.selectFirst();
                return;
            }
            //System.out.println(s);
            if (event.getCode().isLetterKey()) {
                for (T item : items) {
                    if (item.toString().toUpperCase().startsWith(s.toUpperCase())) {

                        filter.add(item);
                        System.out.println(item);

                        setItems(filter);

                        //sm.clearSelection();
                        //sm.select(item);
                    }
                }
                sm.select(0);
            }

        }
    }

    public FilterComboBox() {

        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("FilterComboBox.fxml"));
        fxmlLoader.setRoot(this);
        fxmlLoader.setController(this);
        try {
            fxmlLoader.load();
        } catch (IOException exception) {
            throw new RuntimeException(exception);
        }

        items = getItems();
        this.filter = FXCollections.observableArrayList();

        setOnKeyReleased(new KeyHandler());

        this.focusedProperty().addListener(new ChangeListener() {
            @Override
            public void changed(ObservableValue observable, Object oldValue, Object newValue) {
                if ((boolean) newValue == false) {
                    s = "";
                    setItems(items);
                    getSelectionModel().select((T) selection);
                }
            }
        });

        this.getSelectionModel().selectedItemProperty().addListener(new ChangeListener() {
            @Override
            public void changed(ObservableValue observable, Object oldValue, Object newValue) {
                if (newValue != null) {
                    selection = (Object) newValue;
                }
            }
        });
    }

}

---

你能在加载fxml的地方显示代码吗？只是编辑了文章以反映加载方式我认为你不能将

与动态根fxml（即使用

的根fxml）一起使用：无法设置根元素。您可能只需要执行

，这假设您的

过滤器ComboBox.java

设置正确。谢谢@James\u D。我尝试了创建

过滤器ComboBox

控件的步骤，但是在

PersonDetails.fxml

中（请参阅上文了解稍微不同的版本）我在编辑FXML时遇到一个错误，即FXML加载器无法创建实例

FilterComboBox

（尽管我已经在前言中包含了这些包）。感谢@Uluk Biy，我克服了这个障碍，但现在它给了我一个错误，即它无法将

FilterComboBox字段packages.countries设置为javafx.scene.control.ComboBox

。很抱歉，我没有给出更多细节，因为这是一个复杂设计的一部分，目前这给了我一个InstantiationException@YannisP. 用猜测来回答是困难的。看起来您有两个FXML文件和两个控制器文件。你能不能只发布那些可复制的格式。嗨@Uluk Biy。我已经编辑了这篇文章，包括一个可复制的例子，谢谢@扬尼斯普。否，FXMLLoader将通过反射创建FilterComboBox的实例。默认情况下（如果未使用工厂），它将不调用参数构造函数。您看到的实例化异常就是由于这个原因，即加载程序找不到arg构造函数。参数化构造函数可以在工厂中使用，或者您自己显式创建一个参数化实例，然后调用加载程序的setController。

package persondetails2.controller;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;

/**
 *
 * @author DRY
 */
public class PersonDetailsController implements Initializable {

    @FXML
    private Label label;

    @FXML
    private void handleButtonAction(ActionEvent event) {
        System.out.println("You clicked me!");
        label.setText("Hello World!");
    }

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    

}

public class FilterComboBox<T> extends ComboBox<T> {

    private final ObservableList<T> items;
    private final ObservableList<T> filter;
    private String s;
    private Object selection;

    private class KeyHandler implements EventHandler<KeyEvent> {

        private SingleSelectionModel<T> sm;

        public KeyHandler() {
            sm = getSelectionModel();
            s = "";
            System.err.println("Initialized keyhandler");
        }

        @Override
        public void handle(KeyEvent event) {
            filter.clear();
            // handle non alphanumeric keys like backspace, delete etc
            if (event.getCode() == KeyCode.BACK_SPACE && s.length() > 0) {
                s = s.substring(0, s.length() - 1);
            } else {
                s += event.getText();
            }

            if (s.length() == 0) {
                setItems(items);
                sm.selectFirst();
                return;
            }
            //System.out.println(s);
            if (event.getCode().isLetterKey()) {
                for (T item : items) {
                    if (item.toString().toUpperCase().startsWith(s.toUpperCase())) {

                        filter.add(item);
                        System.out.println(item);

                        setItems(filter);

                        //sm.clearSelection();
                        //sm.select(item);
                    }
                }
                sm.select(0);
            }

        }
    }

    public FilterComboBox() {

        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("FilterComboBox.fxml"));
        fxmlLoader.setRoot(this);
        fxmlLoader.setController(this);
        try {
            fxmlLoader.load();
        } catch (IOException exception) {
            throw new RuntimeException(exception);
        }

        items = getItems();
        this.filter = FXCollections.observableArrayList();

        setOnKeyReleased(new KeyHandler());

        this.focusedProperty().addListener(new ChangeListener() {
            @Override
            public void changed(ObservableValue observable, Object oldValue, Object newValue) {
                if ((boolean) newValue == false) {
                    s = "";
                    setItems(items);
                    getSelectionModel().select((T) selection);
                }
            }
        });

        this.getSelectionModel().selectedItemProperty().addListener(new ChangeListener() {
            @Override
            public void changed(ObservableValue observable, Object oldValue, Object newValue) {
                if (newValue != null) {
                    selection = (Object) newValue;
                }
            }
        });
    }

}

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

<?import java.lang.*?>
<?import javafx.collections.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import persondetails2.controller.*?>

<fx:root type="FilterComboBox"
         xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2">
        <items>
          <FXCollections fx:factory="observableArrayList">
            <String fx:value="Austria" />
            <String fx:value="Denmark" />
            <String fx:value="France" />
            <String fx:value="Germany" />
            <String fx:value="Italy" />
            <String fx:value="Portugal" />
            <String fx:value="Spain" />
          </FXCollections>
        </items>
</fx:root>

<?import persondetails2.controller.FilterComboBox ?>
...

<FilterComboBox GridPane.columnIndex="1" GridPane.rowIndex="2" />