searchexample.java

Java ME手机应用开发大全一书的配套光盘上的源码

import javax.microedition.rms.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.io.*;
public class SearchExample extends MIDlet implements CommandListener
{
  private Display display;
  private Alert alert;
  private Form form; 
  private Command exit; 
  private Command start;
  //声明记录存储对象
  private RecordStore recordstore = null;
  //声明记录存储枚举器对象
  private RecordEnumeration recordEnumeration = null;
  //声明记录存储过滤器对象
  private Filter filter = null;
  public SearchExample ()
  {
    display = Display.getDisplay(this);
    exit = new Command("Exit", Command.SCREEN, 1);
    start = new Command("Start", Command.SCREEN, 1);
    form = new Form("Mixed RecordEnumeration", null);
    form.addCommand(exit);
    form.addCommand(start);
    form.setCommandListener(this);
  }
  public void startApp()
  {
    display.setCurrent(form);
  }
  public void pauseApp()
  {
  }
  public void destroyApp( boolean unconditional )
  {
  }
  public void commandAction(Command command, Displayable displayable)
  {
    if (command == exit)
    {
      destroyApp(true);
      notifyDestroyed();
    }
    else if (command == start)
    {
      try
      {
		//创建或者打开记录存储
        recordstore = RecordStore.openRecordStore(
                          "myRecordStore", true );
      }
      catch (Exception error)
      {
        alert = new Alert("Error Creating", 
                 error.toString(), null, AlertType.WARNING); 
        alert.setTimeout(Alert.FOREVER); 
        display.setCurrent(alert);
      }
      try
      {
		 //声明向记录存储中插入的记录的数据
        String outputData[] = {"Mary", "Bob", "Adam"};
		//向记录存储中添加记录
        for (int x = 0 ; x < 3; x++)
        {
          byte[] byteOutputData = outputData[x].getBytes();
          recordstore.addRecord(byteOutputData, 0, 
                         byteOutputData.length);
        }
      }
      catch ( Exception error)
      {
        alert = new Alert("Error Writing", 
               error.toString(), null, AlertType.WARNING); 
        alert.setTimeout(Alert.FOREVER); 
        display.setCurrent(alert);
      }
      try
      {
		 //实例化过滤器
        filter = new Filter("Bob");
		//使用过滤器作参数实例化枚举器
        recordEnumeration = recordstore.enumerateRecords(
                     filter, null, false);
        //将符合过滤条件的记录显示在屏幕上
		if (recordEnumeration.numRecords() > 0)
        {
          String string = new String(recordEnumeration.nextRecord());
          alert = new Alert("Reading", string, 
                     null, AlertType.WARNING);
          alert.setTimeout(Alert.FOREVER); 
          display.setCurrent(alert); 
        }
      }
      catch (Exception error)
      {
       alert = new Alert("Error Reading", 
                error.toString(), null, AlertType.WARNING); 
       alert.setTimeout(Alert.FOREVER); 
       display.setCurrent(alert);
      }
      try
      {
	   //关闭记录存储
       recordstore.closeRecordStore();
      }
      catch (Exception error)
      {
        alert = new Alert("Error Closing", 
                error.toString(), null, AlertType.WARNING); 
        alert.setTimeout(Alert.FOREVER); 
        display.setCurrent(alert);
      }
	   //判断是否还有对记录存储的打开引用
      if (RecordStore.listRecordStores() != null)
      {
        try
        {
		 //删除记录存储
         RecordStore.deleteRecordStore("myRecordStore");
		 //销毁枚举器对象
         recordEnumeration.destroy();
		 //关闭过滤器
         filter.filterClose();
        }
        catch (Exception error)
        {
         alert = new Alert("Error Removing", 
                  error.toString(), null, AlertType.WARNING); 
         alert.setTimeout(Alert.FOREVER); 
         display.setCurrent(alert);
        }
      }
    }
  }     
}
//声明过滤器类
class Filter implements RecordFilter
{
  //过滤标准
  private String search = null;
  private ByteArrayInputStream inputstream = null;
  private DataInputStream datainputstream = null;
  //构造函数 
  public Filter(String search)
  {
	//通过构造函数初始化过滤标准
    this.search = search.toLowerCase();
  }
  //实现过滤器
  public boolean matches(byte[] suspect)
  {
	  //如果符合标准则返回true，不符合则返回false
    String string = new String(suspect).toLowerCase();
    if (string!= null && string.indexOf(search) != -1)
      return true;
    else
      return false;
  }
  public void filterClose()
  {
    try
    {
      if (inputstream != null)
      {
        inputstream.close();
      }
      if (datainputstream != null)
      {
        datainputstream.close();
      }
    }
    catch ( Exception error)
    {
    }
  }
}