Java2实用教程(第二版)程序代码——第九章 文本框和文本区
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//例子1
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import java.applet.*;import java.awt.*;
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public class Boy extends Applet
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{ TextField text1,text2,text3;
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public void init()
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{ text1=new TextField("输入密码:",10);
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text1.setEditable(false);
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text2=new TextField(10);
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text2.setEchoChar('*');
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text3=new TextField("我是一个文本框",20);
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add(text1);add(text2);add(text3);
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text3.setText("重新设置了文本");
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}
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}
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//例子2
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import java.applet.*;import java.awt.*;import java.awt.event.*;
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public class Example9_2 extends Applet implements ActionListener
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{ TextField text1,text2,text3;
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public void init()
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{ text1=new TextField(10);
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text2=new TextField(10);
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text3=new TextField(20);
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add(text1);add(text2);add(text3);
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text1.addActionListener(this); //将主类的实例作为text1的监视器,
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//因此主类必须实现接口ActionListener 。
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text2.addActionListener(this);
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}
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public void actionPerformed(ActionEvent e)
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{ if(e.getSource()==text1)
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{ String word=text1.getText();
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if(word.equals("boy"))
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{ text3.setText("男孩");
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}
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else if (word.equals("girl"))
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{ text3.setText("女孩");
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}
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else if (word.equals("sun"))
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{ text3.setText("太阳");
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}
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else
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{text3.setText("没有该单词");
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}
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}
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else if(e.getSource()==text2)
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{ String word=text2.getText();
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if(word.equals("男孩"))
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{ text3.setText("boy");
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}
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else if (word.equals("女孩"))
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{ text3.setText("girl");
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}
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else if (word.equals("太阳"))
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{ text3.setText("sun");
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}
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else
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{ text3.setText("没有该单词");
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}
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}
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}
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}
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//例子3
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import java.applet.*;import java.awt.*;import java.awt.event.*;
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public class Example9_3 extends Applet implements ActionListener
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{ TextField text1,text2,text3;
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PoliceMan police;
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public void init()
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{ text1=new TextField(10);
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text2=new TextField(10);
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text3=new TextField(10);
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police=new PoliceMan(this);
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add(text1);add(text2);add(text3);
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text1.addActionListener(this);
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text1.addActionListener(police);
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}
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public void actionPerformed(ActionEvent e)
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{ String number=e.getActionCommand();
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int n=Integer.parseInt(number);
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int m=n*n;text2.setText(n+"的平方是:"+m);
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}
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}
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class PoliceMan implements ActionListener
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{ Example9_3 a=null;
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PoliceMan(Example9_3 a)
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{ this.a=a;
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}
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public void actionPerformed(ActionEvent e)
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{ String number=e.getActionCommand();
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int n=Integer.parseInt(number);
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int m=n*n*n;a.text3.setText(n+"的立方是:"+m);
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}
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}
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//例子4
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import java.applet.*;import java.awt.*;
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public class Example9_4 extends Applet
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{ TextArea text1,text2;
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public void init()
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{ text1=new TextArea("我是学生",6,16);
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text2=new TextArea(6,16);
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add(text1);add(text2);
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text2.append("我在学习java语言");
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text1.insert("们",1);
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text1.selectAll();
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int length=text2.getText().length();
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text2.setSelectionStart(2);
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text2.setSelectionEnd(length);
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}
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}
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//例子5
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import java.util.*;import java.applet.*;
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import java.awt.*;import java.awt.event.*;
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public class Example9_5 extends Applet implements TextListener
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{ TextArea text1,text2;
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public void init()
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{ text1=new TextArea(6,15);
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text2=new TextArea(6,15);
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add(text1);add(text2);
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text2.setEditable(false);
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text1.addTextListener(this) ;
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}
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public void textValueChanged(TextEvent e)
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{ if(e.getSource()==text1)
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{ String s=text1.getText();
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StringTokenizer fenxi=new StringTokenizer(s," ,'\n'");
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int n=fenxi.countTokens();
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String a[]=new String[n];
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for(int i=0;i<=n-1;i++)
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{ String temp=fenxi.nextToken();
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a[i]=temp;
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}
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for(int i=0;i<=n-1;i++) //按字典序从小到大排序。
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{ for(int j=i+1;j<=n-1;j++)
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{ if(a[j].compareTo(a[i])<0)
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{ String t=a[j]; a[j]=a[i]; a[i]=t;
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}
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}
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}
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text2.setText(null); //刷新显示。
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for(int i=0;i<n;i++)
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{ text2.append(a[i]+"\n");
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}
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}
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}
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}
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