app17_13.java

这是大学里的 java课后题的答案

import java.awt.*;
import java.awt.event.*;
public class app17_13 extends  Frame implements AdjustmentListener
{
	static app17_13 frm=new app17_13();
	static Scrollbar scr1=new Scrollbar(Scrollbar.HORIZONTAL);
	static Scrollbar scr2=new Scrollbar(Scrollbar.HORIZONTAL);
	static Scrollbar scr3=new Scrollbar(Scrollbar.HORIZONTAL);
	static Label lab1=new Label("Red:137");
	static Label lab2=new Label("Green:128");
	static Label lab3=new Label("Blue:217");
	static Label lab4=new Label();
	private  int red,green,blue;
	public static void main(String args[])
	{
		frm.setTitle("Frame Title");
		frm.setSize(200,150);
		frm.setLayout(null);
		scr1.setBounds(10,30,60,20);
		scr2.setBounds(70,30,60,20);
		scr3.setBounds(130,30,60,20);
		lab1.setBounds(10,55,60,20);
		lab2.setBounds(70,55,60,20);
		lab3.setBounds(130,55,60,20);
		lab4.setBounds(10,80,180,60);
		scr1.setValues(137,2,0,257);
		scr2.setValues(128,2,0,257);
		scr3.setValues(217,2,0,257);
		lab1.setBackground(new Color(137,0,0));
		lab1.setForeground(Color.white);
		lab2.setBackground(new Color(0,128,0));
		lab2.setForeground(Color.white);
		lab3.setBackground(new Color(0,0,217));
		lab3.setForeground(Color.white);
		lab4.setBackground(new Color(137,128,217));
		frm.add(scr1);
		frm.add(scr2);
		frm.add(scr3);
		frm.add(lab1);
		frm.add(lab2);
		frm.add(lab3);
		frm.add(lab4);
		scr1.addAdjustmentListener(frm);
		scr2.addAdjustmentListener(frm);
		scr3.addAdjustmentListener(frm);
		frm.setVisible(true);
		frm.addWindowListener(new WindowAdapter()
   	{
   		public void windowClosing(WindowEvent e)
   		{
   			System.exit(0);
   		}
   	});
		
	}
	public void adjustmentValueChanged(AdjustmentEvent e)
	{
		red=scr1.getValue();
		green=scr2.getValue();
		blue=scr3.getValue();
		lab1.setBackground(new Color(red,0,0));
		lab1.setText("Red:"+red);
		lab2.setBackground(new Color(0,green,0));
		lab2.setText("Green:"+green);
		lab3.setBackground(new Color(0,0,blue));
		lab3.setText("Blue:"+blue);
		lab4.setBackground(new Color(red,green,blue));
		
	}
}