計算JTextArea中的換行符

Question

如何計算JTextArea中的換行符數量？ 有沒有簡單的例子？有什麼建議麼？

非常感謝您！

Answer 1

這裏是this的程序：

import java.awt.*; 
import java.awt.event.*; 
import java.awt.font.*; 
import java.text.*; 
import javax.swing.*; 

public class JTextAreaLineCountDemo extends JPanel {           
    JTextArea textArea;  

    static Font f = new Font("Helvetiva", Font.ITALIC, 50);                   

    public JTextAreaLineCountDemo() {               
    super(new GridBagLayout());                

    String inputStr = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmo, Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmo, Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmo, Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmo"; 
    textArea = new JTextArea(inputStr);  

    textArea.setEditable(false);                
    textArea.setLineWrap(true);                
    textArea.setWrapStyleWord(true);               

    // Add Components to this panel.               
    GridBagConstraints c = new GridBagConstraints();           
    c.gridwidth = GridBagConstraints.REMAINDER;            

    c.fill = GridBagConstraints.BOTH;               
    c.weightx = 1.0;                   
    c.weighty = 1.0;                   
    add(textArea, c);                   

    addComponentListener(new ComponentAdapter() {            
     @Override                    
     public void componentResized(ComponentEvent ce) { 
      **textArea.setFont(new Font("Arial", Font.BOLD, 22));** 
     System.out.println("Line count: " + countLines(textArea));       
     }                      
    });                      
    }                       

    private static int countLines(JTextArea textArea) { 
    AttributedString text = new AttributedString(textArea.getText()); 
    text.addAttribute(TextAttribute.FONT, f); 
    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++; 
    } 

    return noLines; 
    } 

    private static void createAndShowGUI() {              
    JFrame frame = new JFrame("JTextAreaLineCountDemo");          
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);          

    frame.add(new JTextAreaLineCountDemo());             

    frame.pack();                    
    frame.setVisible(true);                 
    }                       

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