学步园

//J2ME  基础学习之字符串

//主要是String和StingBuffer//

//主要是字符串的修改插入等操作

 import javax.microedition.lcdui.*;

 public class Strings extends Canvas
        {
        private String zifu= "我爱北京天安门";
        private String huizhi;
        private char[] zi={'你','是','我','的','女','人'};
        private byte[] fu={51,52,53,54,55,56};
        private StringBuffer nk=new StringBuffer("我爱你啊");
       
        private  char c;
        private byte[] bianhuan;
        public Strings ()
        {
        //定义方法 
        huizhi =new String(); // 空函数
        huizhi= new String(zifu); //以String value为身体
        huizhi= new String(zi);//以字符数组形成
        huizhi= new String(zi,2,2);//字符 其始  偏移
        huizhi= new String(fu);//byte
        huizhi= new String(fu,3,3);
        huizhi= new String(nk);//StringBuffer
        huizhi= new String("我爱北京天安门");
        //读取方法
        c=huizhi.charAt(3); //获取对应位置字符
        bianhuan=new byte[6]; bianhuan=huizhi.getBytes();//转化为字节
        //void getChars(int srcBegin,int srcEnd,char[] dst,int dstBegin) 
        huizhi.getChars(0,2,zi,2);
        //String substring(int beginIndex)
        //String substring(int beginIndex,ine endIndex)
        //huizhi=huizhi.substring(3,5);
        //比较boolean
        //int compartTo(String anotherString)
        //boolean startsWith(String prefix)
        //boolean endsWith(String prefix)
        //boolean equalsIgnoreCase(String anotherString)不分大小写比较
        //boolean equals(Object anobject)
        //boolean regionMatches(boolean ignoreCase,int toffset,String other,int offset,int len)是否分大小写比较
        //boolean regionMatches(int toffset,String other,int offset,int len)不分大小写比较
       
        //字符串搜索方法
        //int indexOf(int ch,int fromIndex)
        //int indexOf(String str)
         //int indexOf(int ch)第一次搜索到字符CH的位置
         //int indexOf(String str,int fromIndex)
        //int lastIndexOf(int char,int fromIndex)其他相同
       
        // 长度
        //int length()
        //String concat(String str) 效果与+相同
        //String replace(char oldchar,char newchar)
        //String toLowerCase()
        //String toUpperCase()//大小写变换
        //String trim()去除首尾空格
       
       
        //StringBuffer 用法
        //StringBuffer()
        //StringBuffer(int length)长度为length
        //StringBuffer(String str)
       
        //添加append (boolean a)
        //append (char a) append (String a)
        nk.append(huizhi);
        huizhi= new String(nk);
        //插入字符串
        //StringBuffer insert(int offset,boolean b)
        //StringBuffer insert(int offset,char b)
        //StringBuffer insert(int offset,String b)
       
        //StringBuffer delete(int start,int end)
         //StringBuffer deleteCharAt(int index)     
        //StringBuffer replace(int start,int end,String str)
       
        //String toString()将StringBuffer转换为String
        //void setLength(int newLength)
        //int capacity()返回字符串长度 但是缓冲长度
        //void ensureCapacity(int minimumCapacity)设置最小空间
        }
       
        protected void paint(Graphics g){
         g.setColor(0x00ffffff);
         g.fillRect(0,0,getWidth(),getHeight());
         g.setColor(0x00000000);
         g.drawString(String.valueOf(zi[3]),0,0,0);
         g.drawString(huizhi,0,30,0);
          g.drawChar(c,0,20,0);
         
                                       }
       }