带搜索的严格自动完成 JComboBox

Question

我正在寻找一种解决方案，我想根据输入在JComboBox 中自动选择项目。我正在使用以下代码：

package autocompletion;

/**
*
* @author admin
*/
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.ComboBoxEditor;
import javax.swing.ComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.JTextComponent;
import javax.swing.text.PlainDocument;

public class AutoCompletion extends PlainDocument {

JComboBox comboBox;
ComboBoxModel model;
JTextComponent editor;
// flag to indicate if setSelectedItem has been called
// subsequent calls to remove/insertString should be ignored
boolean selecting=false;
boolean hidePopupOnFocusLoss;
boolean hitBackspace=false;
boolean hitBackspaceOnSelection;

KeyListener editorKeyListener;
FocusListener editorFocusListener;

public AutoCompletion(final JComboBox comboBox) {
    this.comboBox = comboBox;
    model = comboBox.getModel();
    editor = (JTextComponent) comboBox.getEditor().getEditorComponent();
    editor.setDocument(this);
    comboBox.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            if (!selecting) highlightCompletedText(0);
        }
    });
    editor.addKeyListener(new KeyAdapter() {
        public void keyPressed(KeyEvent e) {
            if (comboBox.isDisplayable()) comboBox.setPopupVisible(true);
        }
    });
    // Bug 5100422 on Java 1.5: Editable JComboBox won't hide popup when tabbing out
    hidePopupOnFocusLoss=System.getProperty("java.version").startsWith("1.5");
    // Highlight whole text when gaining focus
    editor.addFocusListener(new FocusAdapter() {
        public void focusGained(FocusEvent e) {
            highlightCompletedText(0);
        }
        public void focusLost(FocusEvent e) {
            // Workaround for Bug 5100422 - Hide Popup on focus loss
            if (hidePopupOnFocusLoss) comboBox.setPopupVisible(false);
        }
    });
    // Handle initially selected object
    Object selected = comboBox.getSelectedItem();
    if (selected!=null) setText(selected.toString());
    highlightCompletedText(0);
}

public static void enable(JComboBox comboBox) {
    // has to be editable
    comboBox.setEditable(true);
    // change the editor's document
    new AutoCompletion(comboBox);
}

void configureEditor(ComboBoxEditor newEditor) {
    if (editor != null) {
        editor.removeKeyListener(editorKeyListener);
        editor.removeFocusListener(editorFocusListener);
    }

    if (newEditor != null) {
        editor = (JTextComponent) newEditor.getEditorComponent();
        editor.addKeyListener(editorKeyListener);
        editor.addFocusListener(editorFocusListener);
        editor.setDocument(this);
    }
}

 public void remove(int offs, int len) throws BadLocationException {
    // return immediately when selecting an item
    if (selecting) return;
    //System.out.println("remove " + len + " at " + offs);
    super.remove(offs, len);
}

public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {
    // return immediately when selecting an item
    if (selecting) return;
    // insert the string into the document
    super.insertString(offs, str, a);
    // lookup and select a matching item
    Object item = lookupItem(getText(0, getLength()));
    if (item != null) {
        setSelectedItem(item);
    } else {
        // keep old item selected if there is no match
        item = comboBox.getSelectedItem();
        // imitate no insert (later on offs will be incremented by str.length(): selection won't move forward)
        offs = offs-str.length();
        // provide feedback to the user that his input has been received but can not be accepted
        comboBox.getToolkit().beep(); // when available use: UIManager.getLookAndFeel().provideErrorFeedback(comboBox);
    }
    setText(item.toString());
    // select the completed part
    highlightCompletedText(offs+str.length());
}

private void setText(String text) {
    try {
        // remove all text and insert the completed string
        super.remove(0, getLength());
        super.insertString(0, text, null);
    } catch (BadLocationException e) {
        throw new RuntimeException(e.toString());
    }
}


private void highlightCompletedText(int start) {
    editor.setCaretPosition(getLength());
    editor.moveCaretPosition(start);
}

private void setSelectedItem(Object item) {
    selecting = true;
    model.setSelectedItem(item);
    selecting = false;
}

private Object lookupItem(String pattern) {
    Object selectedItem = model.getSelectedItem();
    // only search for a different item if the currently selected does not match
    if (selectedItem != null && startsWithIgnoreCase(selectedItem.toString(), pattern)) {
        return selectedItem;
    } else {
        // iterate over all items
        for (int i=0, n=model.getSize(); i < n; i++) {
            Object currentItem = model.getElementAt(i);
            // current item starts with the pattern?
            if (currentItem != null && startsWithIgnoreCase(currentItem.toString(), pattern)) {
                return currentItem;
            }
        }
    }
    // no item starts with the pattern => return null
    return null;
}

// checks if str1 starts with str2 - ignores case
private boolean startsWithIgnoreCase(String str1, String str2) {
    return str1.toUpperCase().startsWith(str2.toUpperCase());
}

private static void createAndShowGUI() {
    // the combo box (add/modify items if you like to)
    final JComboBox comboBox = new JComboBox(new Object[] {"Ester", "Jordi", "Jordina", "Jorge", "Sergi"});
    enable(comboBox);

    // create and show a window containing the combo box
    final JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(3);
    frame.getContentPane().add(comboBox);
    frame.pack(); frame.setVisible(true);
}


public static void main(String[] args) {
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}
}

当我键入项目的第一个字母时，自动选择工作正常。但是当我尝试从项目的中间输入时，即如果我输入 "ter"，它应该会自动选择 "Ester"。

请告诉我解决方案。

Answer 1

我认为您正在寻找的是键入的单词和列表中的单词之间的“Levenshtein distance”。 Levenshtein 距离 最小的词是最可能的匹配项（尽管请注意可能有多个匹配项，因此您需要弄清楚如何处理这些匹配项）。

我会从两个列表开始，而不仅仅是一个：显示列表和匹配列表。匹配列表将完全小写，以使搜索更容易。从那里开始，尝试学习以下课程，了解如何比较两个单词：https://commons.apache.org/proper/commons-text/jacoco/org.apache.commons.text.similarity/LevenshteinDistance.java.html