JavaFX 中的自动完成组合框

Question

我正在寻找一种将自动完成添加到 JavaFX ComboBox 的方法。

这 AutoFillBox 是已知的，但不是我正在搜索的。我想要的是一个可编辑的 ComboBox，并且在键入列表时应该进行过滤。但我也想在不输入和查看整个项目的情况下打开列表。

任何想法？

原文由 JulianG 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

我找到了适合我的解决方案：

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

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

    public AutoCompleteComboBoxListener(final ComboBox comboBox) {
        this.comboBox = comboBox;
        sb = new StringBuilder();
        data = comboBox.getItems();

        this.comboBox.setEditable(true);
        this.comboBox.setOnKeyPressed(new EventHandler<KeyEvent>() {

            @Override
            public void handle(KeyEvent t) {
                comboBox.hide();
            }
        });
        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;
        } else if(event.getCode() == KeyCode.BACK_SPACE) {
            moveCaretToPos = true;
            caretPos = comboBox.getEditor().getCaretPosition();
        } else if(event.getCode() == KeyCode.DELETE) {
            moveCaretToPos = true;
            caretPos = comboBox.getEditor().getCaretPosition();
        }

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

        ObservableList 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;
    }

}

你可以用

new AutoCompleteComboBoxListener<>(comboBox);

---

它基于 此，我对其进行了定制以满足我的需要。

随意使用它，如果有人可以改进它，请告诉我。

原文由 JulianG 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

首先，您必须在您的项目中创建此类：

 import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.EventHandler;
import javafx.scene.control.ComboBox;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;

public class FxUtilTest {

    public interface AutoCompleteComparator<T> {
        boolean matches(String typedText, T objectToCompare);
    }

    public static<T> void autoCompleteComboBoxPlus(ComboBox<T> comboBox, AutoCompleteComparator<T> comparatorMethod) {
        ObservableList<T> data = comboBox.getItems();

        comboBox.setEditable(true);
        comboBox.getEditor().focusedProperty().addListener(observable -> {
            if (comboBox.getSelectionModel().getSelectedIndex() < 0) {
                comboBox.getEditor().setText(null);
            }
        });
        comboBox.addEventHandler(KeyEvent.KEY_PRESSED, t -> comboBox.hide());
        comboBox.addEventHandler(KeyEvent.KEY_RELEASED, new EventHandler<KeyEvent>() {

            private boolean moveCaretToPos = false;
            private int caretPos;

            @Override
            public void handle(KeyEvent event) {
                if (event.getCode() == KeyCode.UP) {
                    caretPos = -1;
                    if (comboBox.getEditor().getText() != null) {
                        moveCaret(comboBox.getEditor().getText().length());
                    }
                    return;
                } else if (event.getCode() == KeyCode.DOWN) {
                    if (!comboBox.isShowing()) {
                        comboBox.show();
                    }
                    caretPos = -1;
                    if (comboBox.getEditor().getText() != null) {
                        moveCaret(comboBox.getEditor().getText().length());
                    }
                    return;
                } else if (event.getCode() == KeyCode.BACK_SPACE) {
                    if (comboBox.getEditor().getText() != null) {
                        moveCaretToPos = true;
                        caretPos = comboBox.getEditor().getCaretPosition();
                    }
                } else if (event.getCode() == KeyCode.DELETE) {
                    if (comboBox.getEditor().getText() != null) {
                        moveCaretToPos = true;
                        caretPos = comboBox.getEditor().getCaretPosition();
                    }
                } else if (event.getCode() == KeyCode.ENTER) {
                    return;
                }

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

                ObservableList<T> list = FXCollections.observableArrayList();
                for (T aData : data) {
                    if (aData != null && comboBox.getEditor().getText() != null && comparatorMethod.matches(comboBox.getEditor().getText(), aData)) {
                        list.add(aData);
                    }
                }
                String t = "";
                if (comboBox.getEditor().getText() != null) {
                    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;
            }
        });
    }

    public static<T> T getComboBoxValue(ComboBox<T> comboBox){
        if (comboBox.getSelectionModel().getSelectedIndex() < 0) {
            return null;
        } else {
            return comboBox.getItems().get(comboBox.getSelectionModel().getSelectedIndex());
        }
    }

}

要使您的 ComboBox 自动完成，请像这样使用它：

 FxUtilTest.autoCompleteComboBoxPlus(myComboBox, (typedText, itemToCompare) -> itemToCompare.getName().toLowerCase().contains(typedText.toLowerCase()) || itemToCompare.getAge().toString().equals(typedText));

然后，添加一个 StringConverter 如下例（因为 ComboBox 值将返回一个 String 并且必须将其转换为您的对象）：

 myComboBox.setConverter(new StringConverter<>() {

    @Override
    public String toString(YourObject object) {
        return object != null ? object.getName() : "";
    }

    @Override
    public YourObject fromString(String string) {
        return myComboBox.getItems().stream().filter(object ->
                object.getName().equals(string)).findFirst().orElse(null);
    }

});

当您需要从组合框中获取选定的值时，也请务必使用此方法，否则您可能会遇到一些异常，如“类强制转换异常”：

 FxUtilTest.getComboBoxValue(myComboBox);

PS：此方法在 JRE 8.51 和 8.65 之间的版本中存在一些问题，导致一些奇怪的行为，现在这些问题似乎不再发生。如果您遇到一些问题，您可以看到对此答案所做的编辑并获得当时解决问题的旧版本。此方法必须正常工作，如果您遇到任何问题，请告诉我。

原文由 Mateus Viccari 发布，翻译遵循 CC BY-SA 4.0 许可协议