本文介绍了如何计算JTextArea中的行数，包括换行？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
我想要计算JTextArea的行号包括包装文本。我从
i want count the line number of JTextArea include the wrapped text. And I got the nice sample code from Here Thread
但我尝试使用Dynamic JTextArea进行修改。但是行号的计算出错了。
But i try to modified using Dynamic JTextArea. But the calculation of line number goes wrong.
以下是我修改的代码：
package fandi.demo;
import java.awt.font.FontRenderContext;
import java.awt.font.LineBreakMeasurer;
import java.text.AttributedCharacterIterator;
import java.text.AttributedString;
import javax.swing.JTextArea;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
public class JTextAreaCountModified extends javax.swing.JFrame {
public JTextAreaCountModified() {
initComponents();
setLocationRelativeTo(null);
txtResult.getDocument().addDocumentListener(new DocumentListener() {
@Override
public void insertUpdate(DocumentEvent e) {
if(txtResult.getText().length() > 0) {
lblCountLine.setText(String.valueOf(countLines(txtResult)));
} else {
lblCountLine.setText("0");
}
}
@Override
public void removeUpdate(DocumentEvent e) {
if(txtResult.getText().length() > 0) {
lblCountLine.setText(String.valueOf(countLines(txtResult)));
}else {
lblCountLine.setText("0");
}
}
@Override
public void changedUpdate(DocumentEvent e) {
if(txtResult.getText().length() > 0) {
lblCountLine.setText(String.valueOf(countLines(txtResult)));
}else {
lblCountLine.setText("0");
}
}
});
}
// COUNTING LINE GOES HERE...
public static int countLines(JTextArea textArea) {
AttributedString text = new AttributedString(textArea.getText());
FontRenderContext frc = textArea.getFontMetrics(textArea.getFont()).getFontRenderContext();
AttributedCharacterIterator charIt = text.getIterator();
LineBreakMeasurer lineMeasurer = new LineBreakMeasurer(charIt, frc);
float formatWidth = (float) textArea.getSize().width;
lineMeasurer.setPosition(charIt.getBeginIndex());
int noLines = 0;
while (lineMeasurer.getPosition() < charIt.getEndIndex()) {
lineMeasurer.nextLayout(formatWidth);
noLines++;
}
int lineEnter = textArea.getLineCount();
int countLine = noLines + lineEnter;
return countLine-1;
}
// END OF COUNTING METHOD
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jScrollPane1 = new javax.swing.JScrollPane();
txtResult = new javax.swing.JTextArea();
jLabel3 = new javax.swing.JLabel();
lblCountLine = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("JTextArea Line Counting include Wrap");
setResizable(false);
jLabel1.setText("Enter paragraph");
jLabel2.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
jLabel2.setForeground(new java.awt.Color(255, 0, 0));
jLabel2.setText("20 line limit.");
txtResult.setColumns(20);
txtResult.setLineWrap(true);
txtResult.setRows(5);
txtResult.setWrapStyleWord(true);
jScrollPane1.setViewportView(txtResult);
jLabel3.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
jLabel3.setText("Information : ");
lblCountLine.setText("...");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(lblCountLine)
.addGap(0, 0, Short.MAX_VALUE))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 458, Short.MAX_VALUE)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel2)
.addGap(0, 0, Short.MAX_VALUE)))
.addContainerGap())))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 290, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(lblCountLine))
.addContainerGap(13, Short.MAX_VALUE))
);
pack();
}// </editor-fold>//GEN-END:initComponents
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(JTextAreaCountModified.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(JTextAreaCountModified.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(JTextAreaCountModified.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(JTextAreaCountModified.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new JTextAreaCountModified().setVisible(true);
}
});
}
// Variables declaration - do not modify//GEN-BEGIN:variables
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JLabel lblCountLine;
private javax.swing.JTextArea txtResult;
// End of variables declaration//GEN-END:variables
}
请帮助，谢谢：）
推荐答案
参见 getWrappedLines（）来自的方法。
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