这是一个简单的窗体，但运行时不能显示内部窗体，并报空指针异常，这是怎么回事啊...求指教...
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class swing窗体
{ public static void main(String args[])
{ Mywindow win=new Mywindow();
win.validate();
}
}
class Mywindow extends JFrame
{ JButton button1,button2;
JTextArea text;
JScrollPane scroll;
JInternalFrame interframe;
JSplitPane splitOne,splitTwo;
Mywindow()
{ setSize(300,300);
setVisible(true);
Container con=getContentPane();
con.setLayout(new GridLayout(1,2));
button1=new JButton("button1");
button2=new JButton("button2");
text=new JTextArea(6,12);
scroll=new JScrollPane(text);
splitOne=new JSplitPane(JSplitPane.VERTICAL_SPLIT,true,button1,button2);
splitTwo=new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,true,splitOne,scroll);
interframe.setSize(200,200);
interframe.setVisible(true);
Container interCon=interframe.getContentPane();
interCon.setLayout(new FlowLayout());
interCon.add(splitTwo);
JDesktopPane desk=new JDesktopPane();
desk.add(interframe);
getContentPane().add(desk);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
------解决方案--------------------
- Java code
Mywindow() { setSize(300, 300); setVisible(true); Container con = getContentPane(); con.setLayout(new GridLayout(1, 2)); button1 = new JButton("button1"); button2 = new JButton("button2"); text = new JTextArea(6, 12); scroll = new JScrollPane(text); splitOne = new JSplitPane(JSplitPane.VERTICAL_SPLIT, true, button1, button2); splitTwo = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, true, splitOne, scroll); interframe = new JInternalFrame("Remember to init"); 《======= 这里啊 interframe.setSize(200, 200); interframe.setVisible(true); Container interCon = interframe.getContentPane(); interCon.setLayout(new FlowLayout()); interCon.add(splitTwo); JDesktopPane desk = new JDesktopPane(); desk.add(interframe); getContentPane().add(desk); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); }
------解决方案--------------------
interframe没有new - - 2L已经正解了 就不贴代码了
------解决方案--------------------
- Java code
import java.awt.Container;import java.awt.Dimension;import java.awt.FlowLayout;import java.awt.GridLayout;import javax.swing.JButton;import javax.swing.JDesktopPane;import javax.swing.JFrame;import javax.swing.JInternalFrame;import javax.swing.JScrollPane;import javax.swing.JSplitPane;import javax.swing.JTextArea;public class swingFrame { public static void main(String args[]) { Mywindow win = new Mywindow(); win.validate(); }}class Mywindow extends JFrame { JButton button1, button2; JTextArea text; JScrollPane scroll; JInternalFrame interframe = new JInternalFrame();//没有初始化 对三楼无话可说了 JSplitPane splitOne, splitTwo; Mywindow() { setSize(300, 300); setVisible(true); Container con = getContentPane(); con.setLayout(new GridLayout(1, 2)); button1 = new JButton("button1"); button2 = new JButton("button2"); text = new JTextArea(6, 12); scroll = new JScrollPane(text); splitOne = new JSplitPane(JSplitPane.VERTICAL_SPLIT, true, button1, button2); splitTwo = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, true, splitOne, scroll); interframe.setSize(new Dimension(200, 200)); interframe.setVisible(true); Container interCon = interframe.getContentPane(); interCon.setLayout(new FlowLayout()); interCon.add(splitTwo); JDesktopPane desk = new JDesktopPane(); desk.add(interframe); getContentPane().add(desk); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); }}