如何保持JTextArea的大小不变?

时间:2010-03-16 13:08:01

标签: java swing textarea

我在我的应用程序中使用JTextArea的对象来处理发送短信。

我使用了DocumentFilter,只允许在textarea中输入160个字符,但是现在,我希望textarea的大小是常量。如果我不按“输入”键继续写入同一行,或者即使我只按 Enter 键,它也会继续增加。我尝试过使用'滚动条',但问题仍然存在。建议我这个。以下是我的代码。请检查一下。

class Send_sms extends JPanel implements ActionListener,DocumentListener    
{     
    JButton send;  
    JTextArea smst;  
    JLabel title,limit;  
    JPanel mainp,titlep,sendp,wrap,titlewrap,blankp1,blankp2,sendwrap;   
    JScrollPane scroll;  
    Border br,blackbr;  
    Boolean flag = false;  
    PlainDocument plane;
    public static final int LINES = 4;  
    public static final int CHAR_PER_LINE = 40;     
       //character limit 160 for a sms  

    public Send_sms()
        {
        br = BorderFactory.createLineBorder(Color.RED);
        blackbr = BorderFactory.createEtchedBorder(EtchedBorder.RAISED,Color.DARK_GRAY,Color.GRAY);
        setBorder(blackbr);

                title = new JLabel("Enter the text you want to send!");
        title.setFont(new Font("",Font.BOLD,17));
        limit = new JLabel(""+charCount+" Characters");
        smst = new JTextArea(LINES,CHAR_PER_LINE);
        smst.setSize(100,100);
        plane = (PlainDocument)smst.getDocument();
        //adding DocumentSizeFilter 2 keep track of characters entered
        plane.setDocumentFilter(new DocumentSizeFilter(charCount));
        plane.addDocumentListener(this);
        send = new JButton("Send");
        send.setToolTipText("Click Here To Send SMS");
        send.addActionListener(this);

        //scroll = new JScrollPane(smst);
        //scroll.setPreferredSize(new Dimension(200,200));
        //scroll.setVerticalScrollBarPolicy(null);
        //scroll.setHorizontalScrollBarPolicy(null);
        smst.setBorder(br);

        blankp1 = new JPanel();
        blankp2 = new JPanel();
        titlep = new JPanel(new FlowLayout(FlowLayout.CENTER));
        titlewrap = new JPanel(new GridLayout(2,1));
        mainp = new JPanel(new BorderLayout());
        sendwrap = new JPanel(new GridLayout(3,1));
        sendp = new JPanel(new FlowLayout(FlowLayout.CENTER));
        wrap = new JPanel(new BorderLayout());

        titlep.add(title);
        titlewrap.add(titlep);
        titlewrap.add(blankp1);

        sendp.add(send);
        sendwrap.add(limit);
        sendwrap.add(blankp2);
        sendwrap.add(sendp);

        wrap.add(smst,BorderLayout.CENTER); 
        mainp.add(titlewrap,BorderLayout.NORTH);
        mainp.add(wrap,BorderLayout.CENTER);
        mainp.add(sendwrap,BorderLayout.SOUTH);
        add(mainp);


              }

    public void actionPerformed(ActionEvent e)
    {
        Vector<Vector<String>> info = new Vector<Vector<String>> ();
        Vector<String> numbers = new Vector<String>();
        if(e.getSource() == send)
        {
            //Call a function to send he message to all the clients using text
            //charCount = 165;
            String msg = smst.getText();
            if(msg.length() == 0)
                JOptionPane.showMessageDialog(null,"Please Enter Message","Error",JOptionPane.ERROR_MESSAGE);
            else
            {
            //  System.out.println("Message:"+msg);

                Viewdata frame = new Viewdata(msg);

                limit.setText(""+charCount+" Characters");
                charCount = 160;
              } 
        }
    }
    public void insertUpdate(DocumentEvent e)
    {
        System.out.println("The legth:(insert) "+e.getLength());
        for(int i = 0;i<e.getLength(); i++)
        {   
            if(charCount >0)
                charCount--;
            else
                break;
        }
        limit.setText(""+charCount+" Characters");

    }
    public void removeUpdate(DocumentEvent e)
    {
        //System.out.println("The legth(remove): "+e.getLength());
        for(int i = 0;i<e.getLength(); i++)
        {   

            charCount++;

        }
        limit.setText(""+charCount+" Characters");      
    }
    public void changedUpdate(DocumentEvent e)
    {
        //System.out.println("The legth(change): "+e.getLength());

    }   

}//end Send_sms

3 个答案:

答案 0 :(得分:10)

听起来就像是使用

创建文本区域
JTextArea textArea = new JTextArea();

使用此格式时,文本区域没有首选大小,因此它会继续增长。如果您使用:

JTextArea textArea = new JTextArea(2, 30);
JScrollPane scrollPane = new JScrollPane( textArea );

然后文本区域将具有2行和(大约)30列的首选大小。当您在超出首选宽度时键入时,将出现水平滚动条。或者,如果打开包装,则文本将换行并显示垂直滚动条。

答案 1 :(得分:5)

您需要指定:

textArea.setColumns (160);
textArea.setLineWrap (true);
textArea.setWrapStyleWord (false); //default

但真正的问题是你允许输入超过160个字符。您需要创建某种验证器,当已经写入160个字符时,它将跳过所有输入的字符。

答案 2 :(得分:-1)

使用扩展PlainDocument的文档初始化textArea,并在insertString方法中将字符限制为160