import java.awt.*;
import javax.swing.*;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
private class WangPeng extends JFrame implements CaretListener
{ private JTextField text_1,text_2,text_3;
private JComboBox combox_char;
int i;
public WangPeng(Object calculate[])
{super("整数的算术运算");
this.setBounds(300,240,234,300);
this.setBackground(java.awt.Color.lightGray);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.getContentPane().setLayout(new FlowLayout());
text_1=new JTextField ("");
this.getContentPane().add(text_1);
combox_char=new JComboBox(calculate);
this.getContentPane().add(combox_char);
text_2=new JTextField ("");
this.getContentPane().add(text_2);
text_2.addCaretListener(this);
this.getContentPane().add(new JLabel("="));
text_1=new JTextField ("");
this.getContentPane().add(text_3);
this.setVisible(true);
}
public void caretUpdate(CaretEvent e)
{if(e.getSource()==text_2)
i=combox_char.getSelectedIndex();
text_3.getText()=text_2.getText()+"calculate[i]"+text_1getText();
}
public static void main(String args[])
{ Object calculate[]={"+","-","*","/"};
new WangPeng(calculate[]);
}
}
就是一个标签作为=，三个文本框中有两个是作为输入整数 ，另一个作为答案，中间有一个组合框里面有— + * 、/
我到底拿错了
------解决方案--------------------
- Java code
import java.awt.*;import javax.swing.*;import javax.swing.event.CaretEvent;import javax.swing.event.CaretListener;import javax.swing.event.DocumentListener;import java.text.NumberFormat;import javax.swing.event.DocumentEvent;import java.awt.event.ItemListener;import java.awt.event.ItemEvent;import java.awt.event.FocusEvent;import java.awt.event.FocusListener;public class WangPeng extends JFrame{ private static final String[] calculate = {"+","-","*","/"}; private JFormattedTextField text_1,text_2,text_3; private NumberFormat formatter = NumberFormat.getIntegerInstance(); private JComboBox combox_char; public WangPeng() { super("整数的算术运算"); this.setBackground(java.awt.Color.lightGray); this.setDefaultCloseOperation(EXIT_ON_CLOSE); this.getContentPane().setLayout(new FlowLayout()); text_1 = new JFormattedTextField(formatter); text_1.setColumns(10); text_1.setValue(Long.valueOf(0)); this.getContentPane().add(text_1); combox_char=new JComboBox(calculate); this.getContentPane().add(combox_char); text_2 = new JFormattedTextField (formatter); text_2.setValue(Long.valueOf(0)); text_2.setColumns(10); this.getContentPane().add(text_2); this.getContentPane().add(new JLabel("=")); text_3 = new JFormattedTextField (formatter); text_3.setColumns(10); text_3.setEditable(false); this.getContentPane().add(text_3); this.pack(); this.setVisible(true); xxxxxxx(); } private void xxxxxxx(){ FocusListener listener = new FocusListener(){ @Override public void focusGained(FocusEvent e){ compute(); } @Override public void focusLost(FocusEvent e){ compute(); } }; text_1.addFocusListener(listener); text_2.addFocusListener(listener); text_3.addFocusListener(listener); combox_char.addItemListener(new ItemListener(){ public void itemStateChanged(ItemEvent e){ compute(); } }); } private void compute(){ long n1 = ((Long)text_1.getValue()).longValue(); long n2 = ((Long)text_2.getValue()).longValue(); switch (combox_char.getSelectedIndex()) { case 0: text_3.setValue(Long.valueOf(n1+n2)); break; case 1: text_3.setValue(Long.valueOf(n1-n2)); break; case 2: text_3.setValue(Long.valueOf(n1*n2)); break; case 3: if (n2 != 0) { text_3.setValue(Long.valueOf(n1/n2)); } break; default: break; } } public static void main(String args[]) { java.awt.EventQueue.invokeLater(new java.lang.Runnable(){ @Override public void run(){ new WangPeng(); } }); }}