我必须根据用户输入创建一个自动填充ComboBox.

我的代码是这样的：

public class JavaFXApplication1 extends Application {

    @Override
    public void start(Stage primaryStage) {
        ComboBox<String> combo = new ComboBox<>();
        ObservableList<String> list = FXCollections.observableArrayList();
        list.add("A");
        list.add("AND");
        list.add("ANDR");
        list.add("ANDRE");
        list.add("B");
        list.add("BP");
        list.add("BPO");
        combo.setItems(list);
        new AutoCompleteComboBoxListener(combo);

        StackPane root = new StackPane();
        root.getChildren().add(combo);

        Scene scene = new Scene(root, 300, 250);

        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

AutoCompleteComboBoxListener取自此answer.

使用此自动完成工作正常.我在列表大小方面遇到了问题,

运行该应用程序并单击ComboBox下拉列表以查看弹出窗口大小.

>在组合框中键入ANDRE(将在弹出窗口中显示ANDRE选项).现在删除所有字符.(按退格键)
>现在,已填充的列表使用滚动条缩小为一个条目大小.
>再次单击组合框下拉列表以获取完整大小列表.

如何根据内容制作列表大小？

解决方法:

这是因为comboBox.hide();方法未被调用(下拉列表在show上自动更新).

您可以将侦听器改进为：

public class AutoCompleteComboBoxListener<T> implements EventHandler<KeyEvent> {

    private ComboBox<T> comboBox;
    private ObservableList<T> data;
    private boolean moveCaretToPos = false;
    private int caretPos;

    public AutoCompleteComboBoxListener(final ComboBox<T> comboBox) {
        this.comboBox = comboBox;
        data = comboBox.getItems();

        this.comboBox.setEditable(true);
        this.comboBox.setOnKeyReleased(AutoCompleteComboBoxListener.this);
    }

    @Override
    public void handle(KeyEvent event) {


        if(event.getCode() == KeyCode.UP) {
            caretPos = -1;
            moveCaret(comboBox.getEditor().getText().length());
            return;
        } else if(event.getCode() == KeyCode.DOWN) {
            if(!comboBox.isShowing())
                comboBox.show();

            caretPos = -1;
            moveCaret(comboBox.getEditor().getText().length());
            return;
        } 

        if (event.getCode() == KeyCode.RIGHT || event.getCode() == KeyCode.LEFT
                || event.isControlDown() || event.getCode() == KeyCode.HOME
                || event.getCode() == KeyCode.END || event.getCode() == KeyCode.TAB) {
            return;
        }

        comboBox.hide();

        if(event.getCode() == KeyCode.BACK_SPACE) {
            moveCaretToPos = true;
            caretPos = comboBox.getEditor().getCaretPosition();
        } else if(event.getCode() == KeyCode.DELETE) {
            moveCaretToPos = true;
            caretPos = comboBox.getEditor().getCaretPosition();
        }



        ObservableList<T> list = FXCollections.observableArrayList();
        for (int i=0; i<data.size(); i++) {
            if(data.get(i).toString().toLowerCase().startsWith(
                AutoCompleteComboBoxListener.this.comboBox
                .getEditor().getText().toLowerCase())) {
                list.add(data.get(i));
            }
        }
        String t = comboBox.getEditor().getText();

        comboBox.setItems(list);
        comboBox.getEditor().setText(t);
        if(!moveCaretToPos) {
            caretPos = -1;
        }
        moveCaret(t.length());
        if(!list.isEmpty()) {
            comboBox.show();
        }
    }

    private void moveCaret(int textLength) {
        if(caretPos == -1) 
            comboBox.getEditor().positionCaret(textLength);
        else 
            comboBox.getEditor().positionCaret(caretPos);

        moveCaretToPos = false;
    }

}

此更新将确保每次更改搜索字符串时都会隐藏并重新显示下拉列表.