Java编程思想 第4版 练习题 / 第22章 图形化用户界面 / 练习23

/*

* 以SwingConsole为参考创建一个程序，它可以在屏幕上显示旋转的正方形，并且有一个滑块

* 可以控制旋转的速度，还有一个滑块可以控制正方形的尺寸。

*/

package gui;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.Graphics;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JSlider;

import javax.swing.event.ChangeEvent;

import javax.swing.event.ChangeListener;

import static util.SwingConsole.*;

/**

*

* @author Robin Liu

*/

class FillPol extends JPanel{

private static final int POINTNUM = 4;

private int[] xPoint = new int[POINTNUM];

private int[] yPoint = new int[POINTNUM];

private int l;

private int d;

private double r ;

private double dr ;

public FillPol(){

super();

reSize(0);

reRota(0.001);

setBackground(new Color(0,127,127));

}

@Override

public void paintComponent(Graphics g){

super.paintComponent(g);

g.setColor(Color.red);

int maxWidth = getWidth();

int maxHeight = getHeight();

int minL = (int)(Math.min(maxWidth,maxHeight)*.4);

l = minL;

for(int i = 0;i<POINTNUM;i++){

xPoint[i] = (int)(maxWidth/2+(d+l)*(Math.sin(Math.PI*i*2/POINTNUM+r)));

yPoint[i] = (int)(maxHeight/2+(d+l)*(Math.cos(Math.PI*i*2/POINTNUM+r)));

}

g.fillPolygon(xPoint,yPoint,POINTNUM);

r -= dr;

repaint();

}

public void reSize(int newD){

d = newD;

repaint();

}

public void reRota(double newR){

dr = newR;

repaint();

}

}

public class Polygon extends JFrame{

private FillPol p = new FillPol();

private JSlider ss = new JSlider(0,200,100);

private JSlider rs = new JSlider(1,100,1);

public Polygon(){

ss.addChangeListener(new ChangeListener(){

public void stateChanged(ChangeEvent e){

p.reSize(((JSlider)e.getSource()).getValue()-100);

}

});

rs.addChangeListener(new ChangeListener(){

public void stateChanged(ChangeEvent e){

p.reRota((double)((JSlider)e.getSource()).getValue()/1000);

}

});

add(BorderLayout.CENTER,p);

add(BorderLayout.SOUTH,ss);

add(BorderLayout.NORTH,rs);

}

/**

* @param args the command line arguments

*/

public static void main(String[] args) {

// TODO code application logic here

run(new Polygon(),300,300);

}

}