txtfilelist.java

本程序用JavaME语言描述了一个运行在手机上的电子书系统

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.Enumeration;

import javax.microedition.io.Connector;
import javax.microedition.io.file.FileConnection;
import javax.microedition.io.file.FileSystemRegistry;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.List;


public class TxtFileList extends List implements CommandListener{
	
	private static final long fileSize = 358400;
	/**
	 * 可以显示的文件类型
	 */
	private static final String[] fileType ={".txt",".TXT"};
	
	/**
	 * 向上文件夹名
	 */
	public static final String UP_DIRECTORY = "..";
	/**
	 * 根目录名
	 */
	public static final String MEGA_ROOT = "/";
	/**
	 * 分隔符
	 */
	public static final char SEP = '/';
	
	/**
	 * 分隔符的字符串形式
	 */
	public static final String SEP_STR = "/";
	
	private static Command CMD_back = new Command("返回",Command.BACK,1);
	private static Command CMD_open = new Command("打开",Command.SCREEN,2);
	private static Command CMD_delete = new Command("删除",Command.SCREEN,2);
	private static Command CMD_Yes = new Command("是",Command.OK,2);
	private static Command CMD_No = new Command("否",Command.CANCEL,1);
	private static Command CMD_partition = new Command("分割文件",Command.SCREEN,2);
	private static Command CMD_YesForPartition = new Command("是",Command.OK,2);
	 
	/**
	 * 当前目录
	 */
	private String curDir;
	
	/**
	 * 当前关联的MIDlet
	 */
	private TxtReader bookReader;
	
	//各个ICON
	private Image InfoIcon = null;
	private Image ErrorIcon = null;
	private Image FileIcon = null;
	private Image FolderIcon = null;
	
	//内部线程类，用于运行Open方法
	private class openThread extends Thread{
		private TxtFileList TFL;
		
		public openThread(TxtFileList l){
			TFL = l;
		}

		public void run() {
			TFL.open(TFL.getString(TFL.getSelectedIndex()));
		}
	}
	
	private class deleteThread extends Thread{
		private TxtFileList TFL;
		
		public deleteThread(TxtFileList l){
			TFL = l;
		}
		public void run(){
			TFL.deleteFile(TFL.getString(TFL.getSelectedIndex()));
		}
	}
	
	/**构造一个TxtFileList
	 * @param title 标题
	 * @param listType 列表类型，同List
	 * @param MID 关联的MIDlet
	 */
	public TxtFileList(TxtReader MID){
		super("File List",List.IMPLICIT);
		curDir = MEGA_ROOT;
		bookReader = MID;
		try{
			ErrorIcon = Image.createImage("/icon/Error.png");
			InfoIcon = Image.createImage("/icon/Info.png");
			FileIcon = Image.createImage("/icon/File.png");
			FolderIcon = Image.createImage("/icon/Folder.png");
		} catch (Exception e){
			e.printStackTrace();
		}
		this.addCommand(CMD_back);
		this.addCommand(CMD_open);
		this.addCommand(CMD_delete);
		this.addCommand(CMD_partition);
		this.setSelectCommand(CMD_open);
		this.setCommandListener(this);
	}
	
	/**
	 * 获得当前目录的所有文件和文件夹
	 */
	private boolean getCurDirList() {
        Enumeration e = null;
        FileConnection currDir = null;//当前目录

        try {
        	/*当前目录是根目录*/
            if (MEGA_ROOT.equals(curDir)) {
                e = FileSystemRegistry.listRoots();
            } 
            else {
            	/*当前目录不是根目录*/
                currDir = (FileConnection)Connector.open("file://localhost/" + curDir);
                e = currDir.list();//获得目录列表
            }

        } catch (IOException ioe) {
            ioe.printStackTrace();
        } catch (SecurityException se){
        	return false;
        }
        
        if(0 != this.size()){
        	this.deleteAll();
        }
        
        //当不是根目录时
        if(!MEGA_ROOT.equals(curDir)){
            this.append(UP_DIRECTORY, FolderIcon);//添加向上目录
        }

        List temp = new List("temp",List.IMPLICIT); //临时列表存放文件
        while (e.hasMoreElements()) {
            String fileName = (String)e.nextElement();
            //若是文件夹则添加到当前列表
            if (fileName.charAt(fileName.length() - 1) == SEP) {
            	this.append(fileName, FolderIcon);
            } 
            //否则为文件，符合条件则添加到临时列表
            else {
            	String appendName = fileName.substring(fileName.length() - 4);
            	for(int i = 0 ; i < fileType.length ; i++){
            		if(appendName.equals(fileType[i])){
                		temp.append(fileName, null);
                		break;
                	}
            	}
            }
        }
        
        for(int i = 0 ; i < temp.size();i++){
        	this.append(temp.getString(i), FileIcon) ;
        }
        
        temp.deleteAll();
        temp = null;
        e = null;
        return true;
    }
	
	
	/**转入目标目录，获得目录中的所有文件和文件夹，并显示
	 * @param dirName 目录名
	 */
	private void traverseDir(String dirName) {
		String lastDir = curDir;
        if (curDir.equals(MEGA_ROOT)) {
            if (dirName.equals(UP_DIRECTORY)) {
                return;
            }

            curDir = dirName;
        } else if (dirName.equals(UP_DIRECTORY)) {
            int i = curDir.lastIndexOf(SEP, curDir.length() - 2);

            if (i != -1) {
                curDir = curDir.substring(0, i + 1);
            }
            else {
                curDir = MEGA_ROOT;
            }
        } 
        else {
            curDir = curDir + dirName;
        }
        if(!getCurDirList())
        	curDir = lastDir;
        Display.getDisplay(bookReader).setCurrent(this);
    }
	
	/**打开目标文件
	 * @param fileName 目标文件名
	 */
	private void openFile(String fileName){
		String path = "file://localhost/" + curDir + fileName;
		long size = 0;
		try{
			FileConnection fc = (FileConnection)Connector.open(path);
			size = fc.fileSize();
		} catch(IOException e){
			Display.getDisplay(bookReader).setCurrent( new Alert("错误","文件不存在!",ErrorIcon,AlertType.ERROR),this);
			e.printStackTrace();
		} catch(SecurityException se){
			return;
		}
		//到这里已经可以确定文件存在
		if(size > TxtFileList.fileSize){
			Alert partitionAlert = new Alert("提示","该文件过大,请分割文件后打开,是否要分割这个文件?",InfoIcon,AlertType.INFO);
			partitionAlert.addCommand(CMD_No);
			partitionAlert.addCommand(CMD_YesForPartition);
			partitionAlert.setCommandListener(this);
			Display.getDisplay(bookReader).setCurrent(partitionAlert,this);
		}else {
			HistoryRecordList hrl = (HistoryRecordList)bookReader.getDisplayable(TxtReader.HISTORYRECORDLIST);
			hrl.addFile(fileName,path);
			//目录重置
			curDir = MEGA_ROOT;
			this.getCurDirList();
			ReadingBoard  d = (ReadingBoard)bookReader.getDisplayable(TxtReader.READINGBORD);
			//每次打开文件时对空间进行回收
			System.gc();
			//这个为判断是否许可读取文件,不许可则保持在当前列表
			if (d.selectFile(path, false)){
				Display.getDisplay(bookReader).setCurrent(d);
			}
		}
	}
	
	/**响应CMD_open Command命令的方法
	 * @param fileName 文件名或文件夹名
	 */
	private void open(String fileName){
		//若是文件夹
		if(fileName.charAt(fileName.length() - 1) == TxtFileList.SEP || fileName.equals(TxtFileList.UP_DIRECTORY)){
			this.traverseDir(fileName);
			
		}else{
			this.openFile(fileName);
		}
	}
	
	/**
	 * 返回主界面
	 */
	
	/**删除指定文件
	 * @param fileName 指定文件名
	 */
	private void deleteFile(String fileName){
		if(fileName.endsWith(SEP_STR) || fileName.equals(UP_DIRECTORY)){
			Alert errAlert = new Alert("错误","不能删除文件夹!",ErrorIcon,AlertType.ERROR);
			Display.getDisplay(bookReader).setCurrent(errAlert,this);
		}else {
			try{
				FileConnection fc = (FileConnection)Connector.open("file://localhost/" + curDir + fileName);
				fc.delete();
				getCurDirList();
				Display.getDisplay(bookReader).setCurrent(this);
			}catch(Exception e){
				Alert errAlert = 
					new Alert("错误","不能删除 " + "在" + curDir + "目录下的文件"+ fileName +
	                    "\nException: " + e.getMessage(), ErrorIcon, AlertType.ERROR);
				errAlert.setTimeout(Alert.FOREVER);
				Display.getDisplay(bookReader).setCurrent(errAlert);
			}
		}
	}
	
	private void partitionFile(String path){
		FileConnection fc = null;
		boolean needPartition = false;
		InputStream is = null;
		try{
			fc = (FileConnection)Connector.open(path);
			if(fc.isDirectory())
				Display.getDisplay(bookReader).setCurrent(new Alert("错误","请选择文件!",ErrorIcon,AlertType.ERROR),this);
			else if(fc.fileSize() > TxtFileList.fileSize)
				needPartition = true;
			is = fc.openInputStream();
		} catch(Exception e){
			System.out.println("Error! here" + e.getMessage());//
			e.printStackTrace();
		}
		if(needPartition){
			FileConnection fcTemp = null;
			String subPath = path.substring(0, path.length() - 4);
			String type = ".txt";
			//数据
			char[] data = new char[(int)TxtFileList.fileSize / 2];
			//读入的长度
			int length = 0;
			try{
				InputStreamReader isr = new InputStreamReader(is);
				OutputStream os = null;
				OutputStreamWriter osr = null;
				for(int i = 0;;i++){
					length = isr.read(data);
					if (length==-1){
						break;
					}
					fcTemp = (FileConnection)Connector.open(subPath + i + type);
					if(fcTemp.exists()){
						fcTemp.close();
						i++;
						continue;
					}
					fcTemp.create();
					os = fcTemp.openOutputStream();
					osr = new OutputStreamWriter(os);
					if (length==(int)TxtFileList.fileSize / 2)
						osr.write(data);
					else
						osr.write(data, 0, length + 10);
					os.close();
					fcTemp.close();
					data = new char[(int)TxtFileList.fileSize / 2];
					System.gc();
				}
				os.close();
				is.close();
				fc.close();
			} catch(Exception e){
				e.printStackTrace();
			}
		} else{
			Display.getDisplay(bookReader).setCurrent(new Alert("提示","该文件不需要分割!",InfoIcon,AlertType.INFO), this);
		}
		
	}
	
	private class partitionThread extends Thread{
		private TxtFileList TFL;
		
		public partitionThread(TxtFileList l){
			TFL = l;
		}
		public void run(){
			String path = "file://localhost/" + curDir + TFL.getString(TFL.getSelectedIndex());
			System.out.println(path);//
			//if(path.charAt(path.length() - 1) != TxtFileList.SEP){
				TFL.partitionFile(path);
				TFL.getCurDirList();
				Display.getDisplay(bookReader).setCurrent(TFL);
			//}
		}
	}
	
	public void showList(){
		if(getCurDirList())
			Display.getDisplay(bookReader).setCurrent(this);
		else
			Display.getDisplay(bookReader).setCurrent(bookReader.getDisplayable(TxtReader.MAINMANU));
	}
	
	private class backThread extends Thread{
		private TxtFileList TFL;
		
		public backThread(TxtFileList l){
			TFL = l;
		}
		public void run(){
			TFL.curDir = TxtFileList.MEGA_ROOT;
			if(TFL.getCurDirList())
				Display.getDisplay(bookReader).setCurrent(bookReader.getDisplayable(TxtReader.MAINMANU));
			else
				Display.getDisplay(bookReader).setCurrent(TFL);
		}
	}

	public void commandAction(Command c, Displayable d) {
		if(c == CMD_back){
			new backThread(this).start();
		}else if(c == CMD_open){
			new openThread(this).start();
		}else if(c == CMD_delete){
			Alert warningAlert = new Alert("确认","删除这个文件?",InfoIcon,AlertType.INFO);
			warningAlert.addCommand(CMD_No);
			warningAlert.addCommand(CMD_Yes);
			warningAlert.setCommandListener(this);
			Display.getDisplay(bookReader).setCurrent(warningAlert);
		}else if(c == CMD_Yes){
			new deleteThread(this).start();
		}else if(c == CMD_partition){
			new partitionThread(this).start();
		}else if(c == CMD_YesForPartition){
			new partitionThread(this).start();
		}else {
			Display.getDisplay(bookReader).setCurrent(this);
		}
		
	}

}