【发布时间】：2012-12-25 08:54:58
【问题描述】：
我正在尝试在一个 JFrame 表单上添加三个面板。如果我只添加三个面板，它们将被显示，但如果我在拆分窗格上添加面板，则不会显示任何内容 提示以下代码中的错误
import javax.swing.*;
import java.awt.*;
class paneltest extends JFrame{
paneltest()
{
Container cp=this.getContentPane();
cp.setLayout(null);
panel1 p1= new panel1();
panel2 p2= new panel2();
panel3 p3= new panel3();
cp.add(p1);
cp.add(p2);
cp.add(p3);
Dimension screenSize=Toolkit.getDefaultToolkit().getScreenSize();
p1.setBounds(0,0,screenSize.width/3,screenSize.height);
p2.setBounds(screenSize.width/3,0,screenSize.width/3,screenSize.height);
p3.setBounds(2*(screenSize.width/3),0,screenSize.width/3,screenSize.height);
try{
JSplitPane splitPaneLeft = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
JSplitPane splitPaneRight = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
splitPaneLeft.setLeftComponent( p1 );
splitPaneLeft.setRightComponent( p2 );
splitPaneRight.setLeftComponent( splitPaneLeft );
splitPaneRight.setRightComponent( p3 );
JPanel panelSplit = new JPanel();
panelSplit.add(splitPaneRight);
cp.add(panelSplit);
panelSplit.setVisible(true);
}
catch(Exception ex)
{
JOptionPane.showMessageDialog(null,"exception occured"+ex);
}
}
public static void main(String arsg[])
{
paneltest frm= new paneltest();
frm.show ();
}
}
class panel1 extends JPanel
{
panel1()
{
setLayout(new FlowLayout());
JLabel l1= new JLabel("panel1");
add(l1);
}
}
class panel2 extends JPanel
{
panel2()
{
setLayout(new FlowLayout());
JLabel l1= new JLabel("panel2");
add(l1);
}
}
class panel3 extends JPanel
{
panel3()
{
setLayout(new FlowLayout());
JLabel l1= new JLabel("panel3");
add(l1);
}
}
【问题讨论】：
-
1) 此代码在
cp.setLayout(null);处开始下坡使用布局！ 2) 对代码块使用一致且合乎逻辑的缩进。代码的缩进是为了帮助人们理解程序流程。
标签： java swing jpanel jsplitpane