如何在JTextField中刪除文本？

Question

我的JTextField顯示文件名。如果文件無效，我想刪除線文本。如何做到這一點？我試過html，但沒有運氣。

Answer 1

我敢肯定你不能風格的文本在JTextField，超出設定的字體。我想你要麼必須創建自己的支持樣式的子類，要麼創建一個JTextPane並將其設置爲像JTextField那樣工作。

有一些好的文檔瀏覽：http://download.oracle.com/javase/tutorial/uiswing/components/editorpane.html

Answer 2

笑着可能的，通過使用HTML syntax

2）工具TextAttribute（我喜歡這種方式）

1）

import java.awt.*; 
import java.awt.event.*; 
import java.awt.font.TextAttribute; 
import java.math.RoundingMode; 
import java.text.NumberFormat; 
import java.util.Map; 
import javax.swing.*; 
import javax.swing.border.EmptyBorder; 
import javax.swing.event.*; 

public class TextAttributeSTRIKETHROUGH { 

    private JFrame frame = new JFrame(); 
    private JPanel pnl = new JPanel(); 
    private JLabel focusLabel = new JLabel(" focusLost Handle "); 
    private JFormattedTextField formTextField; 
    private JLabel docLabel = new JLabel(" document Handle "); 
    private JFormattedTextField formTextField1; 
    private NumberFormat formTextFieldFormat; 
    private double amount = 10000.00; 
    private Map attributes; 

    @SuppressWarnings("unchecked") 
    public TextAttributeSTRIKETHROUGH() { 
     formTextFieldFormat = NumberFormat.getNumberInstance(); 
     formTextFieldFormat.setMinimumFractionDigits(2); 
     formTextFieldFormat.setMaximumFractionDigits(2); 
     formTextFieldFormat.setRoundingMode(RoundingMode.HALF_UP); 

     focusLabel.setFont(new Font("Serif", Font.BOLD, 14)); 
     focusLabel.setForeground(Color.blue); 
     focusLabel.setPreferredSize(new Dimension(120, 27)); 
     formTextField = new JFormattedTextField(formTextFieldFormat); 
     formTextField.setValue(amount); 
     formTextField.setFont(new Font("Serif", Font.BOLD, 22)); 
     formTextField.setForeground(Color.black); 
     formTextField.setBackground(Color.yellow); 
     formTextField.setPreferredSize(new Dimension(120, 27)); 
     formTextField.setHorizontalAlignment(SwingConstants.RIGHT); 
     formTextField.addFocusListener(new FocusListener() { 

      @Override 
      public void focusGained(FocusEvent e) { 
       formTextField.requestFocus(); 
       formTextField.setText(formTextField.getText()); 
       formTextField.selectAll(); 
      } 

      public void focusLost(FocusEvent e) { 
       //Runnable doRun = new Runnable() { 

       //@Override 
       //public void run() { 
       double t1a1 = (((Number) formTextField.getValue()).doubleValue()); 
       if (t1a1 < 1000) { 
        formTextField.setValue(amount); 
       } 
       //} 
       // }; 
       //SwingUtilities.invokeLater(doRun); 
      } 
     }); 

     docLabel.setFont(new Font("Serif", Font.BOLD, 14)); 
     docLabel.setForeground(Color.blue); 
     docLabel.setPreferredSize(new Dimension(120, 27)); 

     formTextField1 = new JFormattedTextField(formTextFieldFormat); 
     formTextField1.setValue(amount); 
     formTextField1.setFont(new Font("Serif", Font.BOLD, 22)); 
     formTextField1.setForeground(Color.black); 
     formTextField1.setBackground(Color.yellow); 
     formTextField1.setPreferredSize(new Dimension(120, 27)); 
     formTextField1.setHorizontalAlignment(SwingConstants.RIGHT); 
     formTextField1.addFocusListener(new FocusListener() { 

      @Override 
      public void focusGained(FocusEvent e) { 
       formTextField1.requestFocus(); 
       formTextField1.setText(formTextField1.getText()); 
       formTextField1.selectAll(); 
      } 

      @Override 
      public void focusLost(FocusEvent e) { 
      } 
     }); 
     formTextField1.getDocument().addDocumentListener(docListener); 

     attributes = (new Font("Serif", Font.BOLD, 24)).getAttributes(); 
     attributes.put(TextAttribute.STRIKETHROUGH, TextAttribute.STRIKETHROUGH_ON); 

     pnl = new JPanel(); 
     pnl.setBorder(new EmptyBorder(2, 2, 2, 2)); 
     pnl.setLayout(new GridLayout(2, 2)); 
     pnl.add(focusLabel); 
     pnl.add(formTextField); 
     pnl.add(docLabel); 
     pnl.add(formTextField1); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.add(pnl, BorderLayout.CENTER); 
     frame.setLocation(200, 200); 
     frame.pack(); 
     frame.setVisible(true); 
     formTextFieldFocus1(); 
    } 
    // 
    private DocumentListener docListener = new DocumentListener() { 

     @Override 
     public void changedUpdate(DocumentEvent documentEvent) { 
      printIt(documentEvent); 
     } 

     @Override 
     public void insertUpdate(DocumentEvent documentEvent) { 
      printIt(documentEvent); 
     } 

     @Override 
     public void removeUpdate(DocumentEvent documentEvent) { 
      printIt(documentEvent); 
     } 

     private void printIt(DocumentEvent documentEvent) { 
      DocumentEvent.EventType type = documentEvent.getType(); 
      double t1a1 = (((Number) formTextField1.getValue()).doubleValue()); 
      if (t1a1 < 1000) { 
       Runnable doRun = new Runnable() { 

        @Override 
        public void run() { 
         formTextField1.setFont(new Font(attributes)); 
        } 
       }; 
       SwingUtilities.invokeLater(doRun); 
      } else { 
       Runnable doRun = new Runnable() { 

        @Override 
        public void run() { 
         formTextField1.setFont(new Font("Serif", Font.BOLD, 22)); 
        } 
       }; 
       SwingUtilities.invokeLater(doRun); 
      } 
     } 
    }; 

    private void formTextFieldFocus1() { 
     Runnable doRun = new Runnable() { 

      @Override 
      public void run() { 
       formTextField1.grabFocus(); 
       formTextField1.requestFocus(); 
       formTextField1.setText(formTextField1.getText()); 
       formTextField1.selectAll(); 
      } 
     }; 
     SwingUtilities.invokeLater(doRun); 
    } 

    private void formTextFieldFocus() { 
     Runnable doRun = new Runnable() { 

      @Override 
      public void run() { 
       formTextField.grabFocus(); 
       formTextField.requestFocus(); 
       formTextField.setText(formTextField.getText()); 
       formTextField.selectAll(); 
       formTextFieldFocus1(); 
      } 
     }; 
     SwingUtilities.invokeLater(doRun); 
    } 

    public static void main(String args[]) { 
     EventQueue.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       TextAttributeSTRIKETHROUGH fl = new TextAttributeSTRIKETHROUGH(); 
      } 
     }); 
    } 
}