JAVA例13.16-13.19及例14.3-14.4.docxVIP

例13.16//filename App13_16.javaimportjava.awt.*;importjavax.swing.*;importjavax.swing.event.*;public class App13_16 extends JFrame implements ChangeListener{private JSliderrSlider,gSlider,bSlider; //声明三个JSlider对象privateJTextArea ta=new JTextArea();privateintr,g,b;public App13_16(String s){super(s);rSlider=new JSlider(JSlider.VERTICAL,0,255,0); //创建垂直滑动条rSlider.setMajorTickSpacing(50); //设置主刻度值间隔rSlider.setMinorTickSpacing(10); //设置次刻度值间隔rSlider.setPaintTicks(true); //设置显示两种刻度线rSlider.setPaintLabels(true); //设置显示主刻度值add(rSlider,BorderLayout.WEST); //将JSlider对象rSlider放置在窗口西边gSlider=new JSlider(JSlider.HORIZONTAL,0,255,0);gSlider.setMajorTickSpacing(50);gSlider.setMinorTickSpacing(10);gSlider.setPaintTicks(true);gSlider.setPaintLabels(true);add(gSlider,BorderLayout.SOUTH);bSlider=new JSlider(JSlider.VERTICAL,0,255,0);bSlider.setMajorTickSpacing(50);bSlider.setMinorTickSpacing(10);bSlider.setPaintTicks(true);bSlider.setPaintLabels(true);add(bSlider,BorderLayout.EAST);add(ta,BorderLayout.CENTER);rSlider.addChangeListener(this); //设置本窗口为rSlider对象的监听者gSlider.addChangeListener(this);bSlider.addChangeListener(this);setSize(300,200);}public static void main(String[] args){App13_16 frm=new App13_16(滑动条应用程序);frm.setVisible(true);frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}public void stateChanged(ChangeEvent e) //设置值变化事件处理程序代码{r=rSlider.getValue(); //返回滑块rSlider当前所在位置的值g=gSlider.getValue();b=bSlider.getValue();ta.setBackground(new Color(r,g,b)); //用返回的颜色值设置文本区背景色ta.setText(\n\n 现在（红，绿，蓝）三色的值是（+r+,+g+,+b+）);}}例13.17//利用文件打开对话框打开待编辑的文件，编辑完成后再利用文件保存对话框保存编辑后的文件//filename App13_17.javaimportjava.awt.*;import java.io.*;importjava.util.Scanner;importjava.awt.event.*;import javax.swing.*;public class App13_17 extends JFrame implements ActionListener{private JTextArea ta=new JTextArea(10,20);private JFileChooserjfc=new JFileChooser(new File(.)); //创建文件选择对话框对象jfcprivate JButtonbOpen,bSave;public App13_17(){super(文件选择框应用程序);JScrollPaneps=new JScrollPane(ta); //创建滚动窗格对