使用下拉列表在 Java 中创建自动完成文本框 [英] Create a autocompleting textbox in Java with a dropdown list
本文介绍了使用下拉列表在 Java 中创建自动完成文本框的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想创建一个自动建议文本框，它会在每个按键释放事件中查询数据库.这部分很简单，但我想给它一个漂亮的视觉效果.类似于我们在 Facebook 搜索等网站中看到的自动建议文本框.
I want to create a auto-suggest text box which would query the database at each key release event. That part is easy, but I want to give nice visual to it. Something similar to the auto-suggest text box we see in websites like searching in Facebook.
如何制作这样的界面?
一个天真的想法是将一个 JList 放在文本框的正下方，并在找到结果时将其设置为可见.
A naive idea would be to have a JList placed just below the text box and set it visible with the results in it on finding one.
有什么更好的主意或标准的做法吗?
Any better idea or a standard way of doing it?
推荐答案
@syb0rg 的回答更简单，因为它使用了 3rd 方库.
@syb0rg's answer is easier, as it uses an 3rd party library.
但是我使用了另一种方法:
However I used an alternate approach:
它使用一个名为 AutoSuggestor 的自定义类，它接受一个 JTextField，它的 Window 一个 ArrayList要检查输入的单词的单词数、背景颜色和文本颜色、建议焦点颜色以及不透明度值.通过传递 JTextField 引用，添加了一个 DocumentListener，它会检查输入了哪些单词，是否显示建议，如果是，则显示哪些建议.当输入一个单词时，DocumentListener 将触发wordTyped(String wordTyped) 方法，并使用当前输入的单词或(至少输入了多少单词)，在 wordTyped(..) 中，单词将与 AutoSuggestor 的类 dictionary 中的词进行检查，后者是一个基本的 ArrayListString 的 code> 可以动态设置，如下例所示:
It uses a custom class called AutoSuggestor which accepts a JTextField, its Window an ArrayList<String> of words to check typed words against, a background color and text color, and suggestion focus colour as well as an opacity value. By passing JTextField reference a DocumentListener is added which will do the work of checking what word is typed and whether to display suggestions or not and if so what suggestions to display. When a word is typed the DocumentListener will firewordTyped(String wordTyped) method with the current word being typed or (at least how much ever of the word has been typed), in wordTyped(..) the word will be checked against those in the AutoSuggestors classes dictionary which is a basic ArrayList of String this can be set on the fly as seen in the below example:
(现在您必须使用鼠标并单击要自动完成的单词，或使用 DOWN 横向建议和 textfield 和 使用向下键在遍历时ENTER选择建议.我还没有实现UP):
(For now you will have to use mouse and click the word you want to be auto completed, or use DOWN to transverse suggestions and the textfield and ENTER to select suggestion when traversing using down key. I have not yet implemented UP yet):
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import javax.swing.AbstractAction;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JWindow;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
import javax.swing.border.LineBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
/**
* @author David
*/
public class Test {
public Test() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTextField f = new JTextField(10);
AutoSuggestor autoSuggestor = new AutoSuggestor(f, frame, null, Color.WHITE.brighter(), Color.BLUE, Color.RED, 0.75f) {
@Override
boolean wordTyped(String typedWord) {
//create list for dictionary this in your case might be done via calling a method which queries db and returns results as arraylist
ArrayList<String> words = new ArrayList<>();
words.add("hello");
words.add("heritage");
words.add("happiness");
words.add("goodbye");
words.add("cruel");
words.add("car");
words.add("war");
words.add("will");
words.add("world");
words.add("wall");
setDictionary(words);
//addToDictionary("bye");//adds a single word
return super.wordTyped(typedWord);//now call super to check for any matches against newest dictionary
}
};
JPanel p = new JPanel();
p.add(f);
frame.add(p);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new Test();
}
});
}
}
class AutoSuggestor {
private final JTextField textField;
private final Window container;
private JPanel suggestionsPanel;
private JWindow autoSuggestionPopUpWindow;
private String typedWord;
private final ArrayList<String> dictionary = new ArrayList<>();
private int currentIndexOfSpace, tW, tH;
private DocumentListener documentListener = new DocumentListener() {
@Override
public void insertUpdate(DocumentEvent de) {
checkForAndShowSuggestions();
}
@Override
public void removeUpdate(DocumentEvent de) {
checkForAndShowSuggestions();
}
@Override
public void changedUpdate(DocumentEvent de) {
checkForAndShowSuggestions();
}
};
private final Color suggestionsTextColor;
private final Color suggestionFocusedColor;
public AutoSuggestor(JTextField textField, Window mainWindow, ArrayList<String> words, Color popUpBackground, Color textColor, Color suggestionFocusedColor, float opacity) {
this.textField = textField;
this.suggestionsTextColor = textColor;
this.container = mainWindow;
this.suggestionFocusedColor = suggestionFocusedColor;
this.textField.getDocument().addDocumentListener(documentListener);
setDictionary(words);
typedWord = "";
currentIndexOfSpace = 0;
tW = 0;
tH = 0;
autoSuggestionPopUpWindow = new JWindow(mainWindow);
autoSuggestionPopUpWindow.setOpacity(opacity);
suggestionsPanel = new JPanel();
suggestionsPanel.setLayout(new GridLayout(0, 1));
suggestionsPanel.setBackground(popUpBackground);
addKeyBindingToRequestFocusInPopUpWindow();
}
private void addKeyBindingToRequestFocusInPopUpWindow() {
textField.getInputMap(JComponent.WHEN_FOCUSED).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "Down released");
textField.getActionMap().put("Down released", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent ae) {//focuses the first label on popwindow
for (int i = 0; i < suggestionsPanel.getComponentCount(); i++) {
if (suggestionsPanel.getComponent(i) instanceof SuggestionLabel) {
((SuggestionLabel) suggestionsPanel.getComponent(i)).setFocused(true);
autoSuggestionPopUpWindow.toFront();
autoSuggestionPopUpWindow.requestFocusInWindow();
suggestionsPanel.requestFocusInWindow();
suggestionsPanel.getComponent(i).requestFocusInWindow();
break;
}
}
}
});
suggestionsPanel.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "Down released");
suggestionsPanel.getActionMap().put("Down released", new AbstractAction() {
int lastFocusableIndex = 0;
@Override
public void actionPerformed(ActionEvent ae) {//allows scrolling of labels in pop window (I know very hacky for now :))
ArrayList<SuggestionLabel> sls = getAddedSuggestionLabels();
int max = sls.size();
if (max > 1) {//more than 1 suggestion
for (int i = 0; i < max; i++) {
SuggestionLabel sl = sls.get(i);
if (sl.isFocused()) {
if (lastFocusableIndex == max - 1) {
lastFocusableIndex = 0;
sl.setFocused(false);
autoSuggestionPopUpWindow.setVisible(false);
setFocusToTextField();
checkForAndShowSuggestions();//fire method as if document listener change occured and fired it
} else {
sl.setFocused(false);
lastFocusableIndex = i;
}
} else if (lastFocusableIndex <= i) {
if (i < max) {
sl.setFocused(true);
autoSuggestionPopUpWindow.toFront();
autoSuggestionPopUpWindow.requestFocusInWindow();
suggestionsPanel.requestFocusInWindow();
suggestionsPanel.getComponent(i).requestFocusInWindow();
lastFocusableIndex = i;
break;
}
}
}
} else {//only a single suggestion was given
autoSuggestionPopUpWindow.setVisible(false);
setFocusToTextField();
checkForAndShowSuggestions();//fire method as if document listener change occured and fired it
}
}
});
}
private void setFocusToTextField() {
container.toFront();
container.requestFocusInWindow();
textField.requestFocusInWindow();
}
public ArrayList<SuggestionLabel> getAddedSuggestionLabels() {
ArrayList<SuggestionLabel> sls = new ArrayList<>();
for (int i = 0; i < suggestionsPanel.getComponentCount(); i++) {
if (suggestionsPanel.getComponent(i) instanceof SuggestionLabel) {
SuggestionLabel sl = (SuggestionLabel) suggestionsPanel.getComponent(i);
sls.add(sl);
}
}
return sls;
}
private void checkForAndShowSuggestions() {
typedWord = getCurrentlyTypedWord();
suggestionsPanel.removeAll();//remove previos words/jlabels that were added
//used to calcualte size of JWindow as new Jlabels are added
tW = 0;
tH = 0;
boolean added = wordTyped(typedWord);
if (!added) {
if (autoSuggestionPopUpWindow.isVisible()) {
autoSuggestionPopUpWindow.setVisible(false);
}
} else {
showPopUpWindow();
setFocusToTextField();
}
}
protected void addWordToSuggestions(String word) {
SuggestionLabel suggestionLabel = new SuggestionLabel(word, suggestionFocusedColor, suggestionsTextColor, this);
calculatePopUpWindowSize(suggestionLabel);
suggestionsPanel.add(suggestionLabel);
}
public String getCurrentlyTypedWord() {//get newest word after last white spaceif any or the first word if no white spaces
String text = textField.getText();
String wordBeingTyped = "";
if (text.contains(" ")) {
int tmp = text.lastIndexOf(" ");
if (tmp >= currentIndexOfSpace) {
currentIndexOfSpace = tmp;
wordBeingTyped = text.substring(text.lastIndexOf(" "));
}
} else {
wordBeingTyped = text;
}
return wordBeingTyped.trim();
}
private void calculatePopUpWindowSize(JLabel label) {
//so we can size the JWindow correctly
if (tW < label.getPreferredSize().width) {
tW = label.getPreferredSize().width;
}
tH += label.getPreferredSize().height;
}
private void showPopUpWindow() {
autoSuggestionPopUpWindow.getContentPane().add(suggestionsPanel);
autoSuggestionPopUpWindow.setMinimumSize(new Dimension(textField.getWidth(), 30));
autoSuggestionPopUpWindow.setSize(tW, tH);
autoSuggestionPopUpWindow.setVisible(true);
int windowX = 0;
int windowY = 0;
windowX = container.getX() + textField.getX() + 5;
if (suggestionsPanel.getHeight() > autoSuggestionPopUpWindow.getMinimumSize().height) {
windowY = container.getY() + textField.getY() + textField.getHeight() + autoSuggestionPopUpWindow.getMinimumSize().height;
} else {
windowY = container.getY() + textField.getY() + textField.getHeight() + autoSuggestionPopUpWindow.getHeight();
}
autoSuggestionPopUpWindow.setLocation(windowX, windowY);
autoSuggestionPopUpWindow.setMinimumSize(new Dimension(textField.getWidth(), 30));
autoSuggestionPopUpWindow.revalidate();
autoSuggestionPopUpWindow.repaint();
}
public void setDictionary(ArrayList<String> words) {
dictionary.clear();
if (words == null) {
return;//so we can call constructor with null value for dictionary without exception thrown
}
for (String word : words) {
dictionary.add(word);
}
}
public JWindow getAutoSuggestionPopUpWindow() {
return autoSuggestionPopUpWindow;
}
public Window getContainer() {
return container;
}
public JTextField getTextField() {
return textField;
}
public void addToDictionary(String word) {
dictionary.add(word);
}
boolean wordTyped(String typedWord) {
if (typedWord.isEmpty()) {
return false;
}
//System.out.println("Typed word: " + typedWord);
boolean suggestionAdded = false;
for (String word : dictionary) {//get words in the dictionary which we added
boolean fullymatches = true;
for (int i = 0; i < typedWord.length(); i++) {//each string in the word
if (!typedWord.toLowerCase().startsWith(String.valueOf(word.toLowerCase().charAt(i)), i)) {//check for match
fullymatches = false;
break;
}
}
if (fullymatches) {
addWordToSuggestions(word);
suggestionAdded = true;
}
}
return suggestionAdded;
}
}
class SuggestionLabel extends JLabel {
private boolean focused = false;
private final JWindow autoSuggestionsPopUpWindow;
private final JTextField textField;
private final AutoSuggestor autoSuggestor;
private Color suggestionsTextColor, suggestionBorderColor;
public SuggestionLabel(String string, final Color borderColor, Color suggestionsTextColor, AutoSuggestor autoSuggestor) {
super(string);
this.suggestionsTextColor = suggestionsTextColor;
this.autoSuggestor = autoSuggestor;
this.textField = autoSuggestor.getTextField();
this.suggestionBorderColor = borderColor;
this.autoSuggestionsPopUpWindow = autoSuggestor.getAutoSuggestionPopUpWindow();
initComponent();
}
private void initComponent() {
setFocusable(true);
setForeground(suggestionsTextColor);
addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent me) {
super.mouseClicked(me);
replaceWithSuggestedText();
autoSuggestionsPopUpWindow.setVisible(false);
}
});
getInputMap(JComponent.WHEN_FOCUSED).put(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0, true), "Enter released");
getActionMap().put("Enter released", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent ae) {
replaceWithSuggestedText();
autoSuggestionsPopUpWindow.setVisible(false);
}
});
}
public void setFocused(boolean focused) {
if (focused) {
setBorder(new LineBorder(suggestionBorderColor));
} else {
setBorder(null);
}
repaint();
this.focused = focused;
}
public boolean isFocused() {
return focused;
}
private void replaceWithSuggestedText() {
String suggestedWord = getText();
String text = textField.getText();
String typedWord = autoSuggestor.getCurrentlyTypedWord();
String t = text.substring(0, text.lastIndexOf(typedWord));
String tmp = t + text.substring(text.lastIndexOf(typedWord)).replace(typedWord, suggestedWord);
textField.setText(tmp + " ");
}
}
就目前而言，IMO 唯一可能需要的补充是:
As it stands the only possible needed additions IMO is:
- UP 键聚焦弹出式自动建议框中项目的可遍历性，以便我们可以向上移动.
- UP key Focus traversablity for items within the popup autosuggestions box so we can go in a upward direction.
如果有任何问题让我知道我会看看我能做些什么.但似乎运行良好(触摸木头).
If there are any kinks lemme know I'll see what I can do. But Seems to be running fine (touch wood).
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