我在JTextArea中键入时如何显示自动完成功能? [英] How to show autocomplete as I type in JTextArea?
问题描述
当用户键入JTextArea时，我需要显示建议(自动完成)，就像手机T9一样.
I need to show suggestions (autocomplete) as the user types in a JTextArea, kind of like cell phone T9.
我不知道如何在myTextAreaKeyTyped()事件中做到这一点.
I don't know how to do this in myTextAreaKeyTyped() event.
此应用程序是打字助手.它显示了键盘上不存在的字符的变体.
例如.您按"A"，它显示Â:1，Á:2，À:3…如果按1,2或3，将替换"A".
已经完成了，但是变体显示在JFrame底部的JLabel中，因为我不知道该怎么做.
This app is a typing helper. It shows variants of characters non-present on the keyboard.
E.G. You press 'A', it shows Â:1, Á:2 ,À:3… 'A' will be replaced if you press 1,2 or 3.
It's already done, but the variants are shown in a JLabel at the bottom of my JFrame, because I don't know how to do this.
你能帮帮我吗?预先感谢.
Can you please help me out? Thanks in advance.
推荐答案
以下代码段可激发您的灵感.您可能需要重新组织一些代码以使其更具可维护性，但是它应该可以帮助您.
Here is a snippet to get yourself inspired. You will probably need to reorganize a bit the code to make it more maintainable, but it should give you the gist.
基本上，我们侦听关键事件(例如，如果用户粘贴一些文本，我不希望显示建议面板，则我不认为侦听文档事件与之相关)，以及当插入符号出现时在后面至少2个字符的位置，我们使用一个包含JList建议列表的popupmenu提出一些建议(这里的建议确实没有意义，但是将其绑定到字典上并不难).至于您提到的快捷方式，这样做并不难.
Basically, we listen for key events (I don't find it relevant to listen to document events, for example if the user pastes some text, I don't want the suggestion panel to appear), and when the caret has at least 2 characters behind, we make some suggestions, using a popupmenu containing a JList of suggestions (here suggestions are really not meaningful, but it would not be too hard to bind this to a dictionnary). As for the shortcuts you are mentionning, it should not be too hard to do so.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Point;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JTextArea;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.text.BadLocationException;
public class Test {
public class SuggestionPanel {
private JList list;
private JPopupMenu popupMenu;
private String subWord;
private final int insertionPosition;
public SuggestionPanel(JTextArea textarea, int position, String subWord, Point location) {
this.insertionPosition = position;
this.subWord = subWord;
popupMenu = new JPopupMenu();
popupMenu.removeAll();
popupMenu.setOpaque(false);
popupMenu.setBorder(null);
popupMenu.add(list = createSuggestionList(position, subWord), BorderLayout.CENTER);
popupMenu.show(textarea, location.x, textarea.getBaseline(0, 0) + location.y);
}
public void hide() {
popupMenu.setVisible(false);
if (suggestion == this) {
suggestion = null;
}
}
private JList createSuggestionList(final int position, final String subWord) {
Object[] data = new Object[10];
for (int i = 0; i < data.length; i++) {
data[i] = subWord + i;
}
JList list = new JList(data);
list.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 1));
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.setSelectedIndex(0);
list.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
insertSelection();
}
}
});
return list;
}
public boolean insertSelection() {
if (list.getSelectedValue() != null) {
try {
final String selectedSuggestion = ((String) list.getSelectedValue()).substring(subWord.length());
textarea.getDocument().insertString(insertionPosition, selectedSuggestion, null);
return true;
} catch (BadLocationException e1) {
e1.printStackTrace();
}
hideSuggestion();
}
return false;
}
public void moveUp() {
int index = Math.min(list.getSelectedIndex() - 1, 0);
selectIndex(index);
}
public void moveDown() {
int index = Math.min(list.getSelectedIndex() + 1, list.getModel().getSize() - 1);
selectIndex(index);
}
private void selectIndex(int index) {
final int position = textarea.getCaretPosition();
list.setSelectedIndex(index);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
textarea.setCaretPosition(position);
};
});
}
}
private SuggestionPanel suggestion;
private JTextArea textarea;
protected void showSuggestionLater() {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
showSuggestion();
}
});
}
protected void showSuggestion() {
hideSuggestion();
final int position = textarea.getCaretPosition();
Point location;
try {
location = textarea.modelToView(position).getLocation();
} catch (BadLocationException e2) {
e2.printStackTrace();
return;
}
String text = textarea.getText();
int start = Math.max(0, position - 1);
while (start > 0) {
if (!Character.isWhitespace(text.charAt(start))) {
start--;
} else {
start++;
break;
}
}
if (start > position) {
return;
}
final String subWord = text.substring(start, position);
if (subWord.length() < 2) {
return;
}
suggestion = new SuggestionPanel(textarea, position, subWord, location);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
textarea.requestFocusInWindow();
}
});
}
private void hideSuggestion() {
if (suggestion != null) {
suggestion.hide();
}
}
protected void initUI() {
final JFrame frame = new JFrame();
frame.setTitle("Test frame on two screens");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new BorderLayout());
textarea = new JTextArea(24, 80);
textarea.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 1));
textarea.addKeyListener(new KeyListener() {
@Override
public void keyTyped(KeyEvent e) {
if (e.getKeyChar() == KeyEvent.VK_ENTER) {
if (suggestion != null) {
if (suggestion.insertSelection()) {
e.consume();
final int position = textarea.getCaretPosition();
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
try {
textarea.getDocument().remove(position - 1, 1);
} catch (BadLocationException e) {
e.printStackTrace();
}
}
});
}
}
}
}
@Override
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_DOWN && suggestion != null) {
suggestion.moveDown();
} else if (e.getKeyCode() == KeyEvent.VK_UP && suggestion != null) {
suggestion.moveUp();
} else if (Character.isLetterOrDigit(e.getKeyChar())) {
showSuggestionLater();
} else if (Character.isWhitespace(e.getKeyChar())) {
hideSuggestion();
}
}
@Override
public void keyPressed(KeyEvent e) {
}
});
panel.add(textarea, BorderLayout.CENTER);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new Test().initUI();
}
});
}
}
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