shiyan7_6.java

java例子

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class Shiyan7_6 extends Applet implements ActionListener
{
	Button but1;
	Button but2;
	Button but3;
	Button but4;
	TextField text1;
 	TextField text2;
 	TextField text3;
	Label label1;
	Label label2;
	Label label3;
	public void init()
	{
		but1=new Button("     +     ");
		but2=new Button("     -     ");
		but3=new Button("     ×     ");
		but4=new Button("     ÷     ");
		text1=new TextField("              ");
		text2=new TextField("              ");
		text3=new TextField("              ");
		label1=new Label("操作数");
		label2=new Label("操作数");
		label3=new Label("结果");
		GridBagLayout gbl=new GridBagLayout();
		GridBagConstraints gbc=new GridBagConstraints();
		setLayout(gbl);
		gbc.gridx=1;gbc.gridy=2;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(label1,gbc);
		add(label1);

		gbc.gridx=1;gbc.gridy=4;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(label2,gbc);
		add(label2);
		
		gbc.gridx=1;gbc.gridy=6;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(label3,gbc);
		add(label3);
		
		gbc.gridx=2;gbc.gridy=2;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(text1,gbc);
		add(text1);
		
		gbc.gridx=2;gbc.gridy=4;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(text2,gbc);
		add(text2);
		
		gbc.gridx=2;gbc.gridy=6;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(text3,gbc);
		add(text3);
		
		gbc.gridx=3;gbc.gridy=1;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(but1,gbc);
		add(but1);
		but1.addActionListener(this);
		
		gbc.gridx=3;gbc.gridy=3;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(but2,gbc);
		add(but2);
		but2.addActionListener(this);
		
		gbc.gridx=3;gbc.gridy=5;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(but3,gbc);
		add(but3);
		but3.addActionListener(this);
		
		gbc.gridx=3;gbc.gridy=7;
		gbc.gridwidth=1;
		gbc.gridheight=1;
		gbc.weightx=1;gbc.weighty=0;
		gbc.insets=new Insets(2,5,2,5);
		gbl.setConstraints(but4,gbc);
		add(but4);
		but4.addActionListener(this);
	}
	public void actionPerformed(ActionEvent e)
	{
		float x,y,result;
		x=Float.valueOf(text1.getText()).floatValue();
		y=Float.valueOf(text2.getText()).floatValue();
		if(e.getSource()==but1)
		{
			result=x+y;	
			text3.setText(""+result);
		}
		if(e.getSource()==but2)
		{
			result=x-y;
			text3.setText(""+result);
		}
		if(e.getSource()==but3)
		{	
			result=x*y;
			text3.setText(""+result);
		}
		if(e.getSource()==but4)
		{
			result=x/y;
			text3.setText(""+result);
		}
	}
}