filecontroller.java

《j2me开发精解〉（詹健飞）CD-rom附带源码。用netbeans

package com.j2medev.ch8.fc;

import java.io.IOException;
import java.io.InputStream;
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.*;


/**
 *
 * @author Administrator
 */
public class FileController implements CommandListener{
    
    private PowerAudio midlet = null;
    private Display display = null;
    private Image dirImg = null;
    private Image fileImg = null;
    private String currentDir = null;//存储当前目录
    
    public static final String UP_DIR = "返回上级目录";
    public static final String ROOT = "/";
    public static final String SEPARATOR_STR = "/";
    public static final char SEPARATOR = '/';
    public static final Command exitCommand = new Command("退出",Command.OK,1);
    
    public FileController(PowerAudio midlet) {
        this.midlet = midlet;
        currentDir = ROOT;
        if(display == null){
            display = Display.getDisplay(midlet);
        }
        try{
            dirImg = Image.createImage("/dir.png");
            fileImg = Image.createImage("/file.png");
        }catch(IOException ex){
            ex.printStackTrace();
        }
    }
    
    public void setCurrent(Displayable displayable){
        display.setCurrent(displayable);
    }
    
    public void showCurrentDir(){
        List main = new List(currentDir,List.IMPLICIT);
        Enumeration enums = null;
        FileConnection fc = null;
        try{
            //当前目录为根目录
            if(currentDir.equals(ROOT)){
                enums = FileSystemRegistry.listRoots();
            }else{
                main.append(UP_DIR, dirImg);
                fc = (FileConnection)Connector.open("file://"+currentDir);
                enums = fc.list();
            }
            while(enums.hasMoreElements()){
                String obj = (String)enums.nextElement();
                if(obj.charAt(obj.length()-1)==SEPARATOR){
                    //目录结构
                    main.append(obj, dirImg);
                }else{
                    //文件
                    main.append(obj, fileImg);
                }
            }
            if(fc != null){
                fc.close();
            }
            main.addCommand(exitCommand);
            main.setCommandListener(this);
            display.setCurrent(main);
        }catch(IOException ex){
            ex.printStackTrace();
        }
    }
    
    public void tranverse(String fileName){
        if(fileName.equals(UP_DIR)){
            int i = currentDir.lastIndexOf(SEPARATOR, currentDir.length()-2);
            if(i != -1){
                currentDir = currentDir.substring(0, i+1);
            }else{
                currentDir = ROOT;
            }
        }else{
            currentDir = currentDir + fileName;
        }
        showCurrentDir();
    }
    
    public void play(String fileName){
        if(!fileName.endsWith("mid")){
            return;
        }
        String file = "file://"+currentDir+fileName;
        FileConnection fc = null;
        try{
            fc = (FileConnection)Connector.open(file);
            InputStream is = fc.openInputStream();
            if(is != null){
                AudioPlayer player = new AudioPlayer(this);
                player.initVideo(is, fileName);
            }
        }catch(IOException ex){
            ex.printStackTrace();
        }
    }
    
    public void commandAction(Command cmd,Displayable displayable){
        if(cmd == List.SELECT_COMMAND){
            List list = (List)displayable;
            String fileName = list.getString(list.getSelectedIndex());
            if(fileName.endsWith(SEPARATOR_STR) || fileName.equals(UP_DIR)){
                tranverse(fileName);
            }else{
                play(fileName);
            }
        }else if(cmd == exitCommand){
            midlet.exit();
        }
    }
}