动态调整JScrollPane的大小？

Question

我有两个文件.一个扩展JFrame,另一个扩展JPanel.每当我改变帧的大小时,无论是最大化,拖动还是其他什么,我都希望ScrollPane能够适应帧的当前大小.除此之外,还有一个顶级菜单栏和一个底栏,但为了简单起见,我把它们留了下来.

基本上,我希望它像记事本一样工作.

现在,我在框架上使用ComponentListener,在另一个类中调用setSize方法.setSize方法只是:

public void resize(int x, int y)
{
textA.setPreferredSize(new Dimension(x, y-50));

areaScrollPane.setPreferredSize(new Dimension(x,y-50));
}

另外,供参考:

public void componentResized(ComponentEvent e)
 {
     textA.resize(panel.getWidth(),panel.getHeight());
  }

仅供参考,它扩展了JPanel,因为我将其添加到框架中:

panel = (JPanel) this.getContentPane();
panel.setLayout(new BorderLayout());
panel.add(textA, BorderLayout.CENTER);

那么最好的方法是什么？谢谢!

编辑:这是滚动窗格文件.它在我的主要部分称为textA.

    public class TextArea extends JPanel
    {

    JTextArea textA=new JTextArea(500,500);

    JScrollPane areaScrollPane = new JScrollPane(textA);
    Toolkit toolkit =  Toolkit.getDefaultToolkit ();
    Dimension dim = toolkit.getScreenSize();
    Dimension dim2=(new Dimension((int)(dim.getWidth()),(int)(dim.getHeight()-120)));
    public TextArea()
    {
        //textA.setLineWrap(true);
        //textA.setWrapStyleWord(true);
        textA.setEditable(true);
        textA.setForeground(Color.WHITE);

        textA.setBackground(Color.DARK_GRAY);
        this.setFont(null);



        areaScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
        areaScrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        areaScrollPane.setMinimumSize(new Dimension(300,300));
        areaScrollPane.setSize(new Dimension(800,800));
        textA.setPreferredSize(dim2);
        areaScrollPane.setPreferredSize(dim2);
        areaScrollPane.setMaximumSize(dim2);
        add(areaScrollPane);
     }


    @Override
    public void resize(int x, int y)
    {
    textA.setPreferredSize(new Dimension(x, y-50));
    areaScrollPane.setPreferredSize(new Dimension(x,y-50));
    }

    }

主要:

    public class JEdit extends JFrame implements ComponentListener

    {
    TextArea textA=new TextArea();
    JPanel panel;
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {

       JEdit run=new JEdit();

    }

    public JEdit()
    {

        setTitle("JEdit");
        setLayout(new BorderLayout());
        setSize(1100, 1000);

        this.setMinimumSize(new Dimension(100,100));
        //setBackground(Color.BLACK);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException ex) {
           System.out.println("error1");
        } catch (InstantiationException ex) {
            System.out.println("error2");
        } catch (IllegalAccessException ex) {
           System.out.println("error3");
        } catch (UnsupportedLookAndFeelException ex) {
            System.out.println("error4");
        }

         panel = (JPanel) this.getContentPane();
         panel.setLayout(new BorderLayout());
         //TopBar top=new TopBar();
        // PositionBar posB=new PositionBar();
         panel.add(textA, BorderLayout.CENTER);




       // add(top,BorderLayout.NORTH);
       // add(posB,BorderLayout.SOUTH);




        addComponentListener(this);
        setVisible(true);

    }



    public void componentResized(ComponentEvent e)
    {
         textA.resize(panel.getWidth(),panel.getHeight());
    }

    public void componentMoved(ComponentEvent e) {
    textA.resize(panel.getWidth(),panel.getHeight());
    }

    public void componentShown(ComponentEvent e) {
    textA.resize(panel.getWidth(),panel.getHeight());
    }

    public void componentHidden(ComponentEvent e) {
         textA.resize(panel.getWidth(),panel.getHeight());
    }



    }

Answer 1

关于你发布的代码,为了摆脱对setSize的所有调用 - 当使用布局管理器并摆脱所有ComponentListener东西时,这些通常都不受尊重,因为它是多余的,因为你使用布局管理器调整大小.我看到的最大问题是你允许你的TextArea JPanel使用它的默认布局,即FlowLayout,这样做会阻止它所持有的JScrollPane大小调整.给这个类一个BorderLayout(或者更好的只是从类中返回一个JScrollPane),然后你就可以了.例如,通过快速修改和重命名类来防止与标准Java类发生冲突,

import java.awt.*;
import javax.swing.*;

@SuppressWarnings("serial")
public class JEdit2 extends JFrame  {
   TextArea2 textA = new TextArea2();
   JPanel panel;

   public static void main(String[] args) {
      new JEdit2();
   }

   public JEdit2() {
      setTitle("JEdit 2");
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      panel = (JPanel) this.getContentPane();
      panel.add(textA, BorderLayout.CENTER);

      pack(); //!! added
      setLocationRelativeTo(null);
      setVisible(true);
   }

}

@SuppressWarnings("serial")
class TextArea2 extends JPanel {
   JTextArea textA = new JTextArea(500, 500); // !! this is one friggin' huge JTextArea!
   JScrollPane areaScrollPane = new JScrollPane(textA);

   public TextArea2() {
      textA.setEditable(true);
      textA.setForeground(Color.WHITE);
      textA.setBackground(Color.DARK_GRAY);
      this.setFont(null);

      setLayout(new BorderLayout()); //!! added
      add(areaScrollPane, BorderLayout.CENTER);
   }
}