【发布时间】：2014-04-11 04:38:51
【问题描述】：
我希望这不是太具体，但我无法理解递归方法的逻辑流程。
目标：创建一个书籍类型的 gui，它将显示文本，保持换行，在 2 个 JTextArea 之间使用自动换行和页面换行。我不想通过滚动窗格来执行此操作，并且希望获得带有用于向左/向右翻转页面的按钮的书籍效果。
[伪]代码：将文本拉入并操作为（等宽拟合）行，将 X 行放入页面中。如果存在上一页/下一页，则启用左/右按钮。左侧显示 x 页，右侧显示 x+1 页。使用 (leftPageCursor) 来保持当前左页。
为了做到这一点，我的想法是有一个递归显示方法，它“显示/隐藏”左/右按钮，将文本放在 JTextAreas 上，并添加按钮侦听器代码。它在第一次单击右侧时起作用，但随后变得非常混乱并且 (leftPageCursor) 失控。我为任何人创建了以下 SSCCEE 以了解我的意思/逻辑。
我真的很感激任何帮助，我没有想法。我尝试了很多事情，最后一个（例如消费）没有成功。
SSCCEE：（请原谅篇幅过长 - 我希望它在运行的同时保持良好的评论）
public class ReadJIntLauncher extends JFrame {
private static final long serialVersionUID = 1L;
static JTextArea textAreaLeft, textAreaRight;
static JButton btnPageLeft, btnPageRight;
static int leftPageCursor = 0, readMessageId = 1;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
ReadJIntLauncher frame = new ReadJIntLauncher();
frame.setVisible(true);
HashMap<String, String> messages = new HashMap<String, String>();
messages.put("read_paragraph_1_0", "PAGE 1: Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor");
messages.put("read_paragraph_1_1", "incididunt ut labore etdolore magna aliqua. Ut enim ad minim veniam, quis nostrud");
messages.put("read_paragraph_1_2", "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute");
messages.put("read_paragraph_1_3", "irure dolor in reprehenderit in voluptate velit esseees");
messages.put("read_paragraph_1_4", "PAGE 2: cillum dolore deserunt anim id est laborum anim id est laborum incididunt ut");
messages.put("read_paragraph_1_5", "labore incididunt ut labore etdolore magna aliqua. Ut enim ad minim veniam, quis");
messages.put("read_paragraph_1_6", "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute");
messages.put("read_paragraph_1_7", "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.");
messages.put("read_paragraph_1_8", "PAGE 3: Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor");
messages.put("read_paragraph_1_9", "incididunt ut labore etdolore magna aliqua. Ut enim ad minim veniam, quis nostrud");
messages.put("read_paragraph_1_10", "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute");
messages.put("read_paragraph_1_11", "irure dolor in reprehenderit in voluptate velit esseees");
messages.put("read_paragraph_1_12", "PAGE 4: cillum dolore deserunt anim id est laborum anim id est laborum incididunt ut");
messages.put("read_paragraph_1_13", "labore incididunt ut labore etdolore magna aliqua. Ut enim ad minim veniam, quis");
messages.put("read_paragraph_1_14", "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute");
messages.put("read_paragraph_1_15", "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.");
messages.put("read_paragraph_1_16", "PAGE 5: Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor");
messages.put("read_paragraph_1_17", "incididunt ut labore etdolore magna aliqua. Ut enim ad minim veniam, quis nostrud");
messages.put("read_paragraph_1_18", "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.");
final HashMap<Integer, String> readLines = new HashMap<Integer, String>();
int lineCount = 0;
String entireText = "";
//grab all of the messages into entireText
for (int i = 0; i < Integer.MAX_VALUE; i++){
if (messages.containsKey("read_paragraph_" + readMessageId + "_" + i)){
String read = messages.get("read_paragraph_" + readMessageId + "_" + i);
entireText += read + " |";
} else {
break;
}
}
//split the entire text by spaces
String[] readSplitSpaces = entireText.split("\\s");
//put words into readLines
String singleLine = "";
for (String s : readSplitSpaces){
s = s + " ";
int wordLength = s.length();
if (s.contains("|")){
String[] sSplitStrings = s.split("\\|");
singleLine += sSplitStrings[0];
readLines.put(lineCount, singleLine);
lineCount++;
singleLine = sSplitStrings[1];
} else {
if ((singleLine.length() + wordLength) <= 26){
singleLine += s;
} else {
readLines.put(lineCount, singleLine);
lineCount++;
singleLine = s;
}
}
}
//print out readLines
for (int i = 0; i < Integer.MAX_VALUE; i++){
if (readLines.containsKey(i)){
System.out.println("[" + i + "] : " + readLines.get(i));
} else { break; }
}
//put readLines into readPages
final HashMap<Integer, String> readPages = new HashMap<Integer, String>();
int totalPageCount = lineCount / 15;
if (lineCount % 15 != 0){ //round up for partial pages
totalPageCount++;
}
for (int i = 0; i < totalPageCount; i++){
String tmpPage = "";
for (int k = 0; k < 15; k++){
if (readLines.containsKey(k + (i * 15))){
tmpPage += readLines.get(k + (i * 15)) + "\r\n";
}
}
readPages.put(i, tmpPage); //i is pageCount
}
//print out readPages
for (int i = 0; i < Integer.MAX_VALUE; i++){
if (readPages.containsKey(i)){
System.out.println("[" + i + "] : " + readPages.get(i));
} else { break; }
}
displayReadPages(readPages);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public ReadJIntLauncher() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 600, 430);
JPanel jint = new JPanel();
jint.setBounds(100, 100, 534, 428);
jint.setLayout(null);
textAreaLeft = new JTextArea();
textAreaLeft.setFont(new Font("Monospaced", Font.PLAIN, 14));
textAreaLeft.setBounds(25, 37, 213, 297);
jint.add(textAreaLeft);
textAreaRight = new JTextArea();
textAreaRight.setFont(new Font("Monospaced", Font.PLAIN, 14));
textAreaRight.setBounds(261, 37, 213, 297);
jint.add(textAreaRight);
btnPageLeft = new JButton("left");
btnPageLeft.setBounds(10, 345, 89, 23);
jint.add(btnPageLeft);
btnPageRight = new JButton("right");
btnPageRight.setBounds(385, 345, 89, 23);
jint.add(btnPageRight);
getContentPane().add(jint);
}
public static void displayReadPages(final HashMap<Integer, String> readConvo){
System.out.println("\nonLeftPage: " + leftPageCursor);
//enable buttons if necessary
if (leftPageCursor != 0){
btnPageLeft.setEnabled(true);
} else {
btnPageLeft.setEnabled(false);
}
if (readConvo.containsKey(leftPageCursor + 2)){
btnPageRight.setEnabled(true);
} else {
btnPageRight.setEnabled(false);
}
//set left and right page(possibly)
textAreaLeft.setText(readConvo.get(leftPageCursor)); System.out.println(" left page: " + leftPageCursor);
if (readConvo.containsKey(leftPageCursor + 1)) {
textAreaRight.setText(readConvo.get(leftPageCursor + 1)); System.out.println(" right page: " + (leftPageCursor + 1));
} else {
textAreaRight.setText("");
}
btnPageLeft.addMouseListener(new MouseListener() {
public void mouseClicked(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON1){
leftPageCursor -= 2;
displayReadPages(readConvo);
}
}
});
btnPageRight.addMouseListener(new MouseListener() {
public void mouseClicked(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON1){
leftPageCursor += 2;
displayReadPages(readConvo);
}
}
});
}
}
【问题讨论】：
标签： java swing recursion mouseevent jtextarea