J2ME文件系統的運用（四） LWUIT文件瀏覽器

這一篇是前面幾篇的綜合，前面幾篇是基礎，文件瀏覽器無非就是遍歷目錄，查看文件。J2ME文件瀏覽器的源碼網上已經有了，是MIDP寫的，我把它改造爲LWUIT版本。這兩種方式的文件瀏覽器我都在真機上測試通過，不過MIDP版本的在讀取文本文件時，中文出現亂碼，原因是它採用的是GBK編碼形式，在源碼中把格式換成UTF-8就可以了。

文件瀏覽器的原理比較簡單，手機需要支持JSR75,根據前面的知識還是比較容易做出來的。
下面是簡單的流程圖：
 

用LWUIT做文件瀏覽器只需要3個Form：

• ListForm，包含List組件，用於顯示文件和文件夾列表
• ImageForm，包含Button組件，Button用於盛裝圖片
• TextForm，包含TextArea組件，用戶盛裝文本

無圖無真相，還是先看看效果：

 

 

 

 

 

 

 

源代碼下載地址（通過測試）
LWUIT版本的：http://download.csdn.net/source/1945144
MIDP版本的：http://download.csdn.net/source/1945133

代碼：

IconHelper.java圖標幫助類，根據文件擴展名顯示相應圖標

package main; /* File: IconHelper.java Purpose: 圖標幫助類 Functions: getIconByExt public 按照擴展名（不包括'.'符號）獲取文件的圖標對象 History: %yongsongw% @ 2008-8-1: created. Copyright (C) 2008 Fool studio. All rights reserved. */ import java.util.Hashtable; import com.sun.lwuit.Image; import java.io.IOException; public class IconHelper { //圖標資源 private Image imgFolder; private Image unknownImage; private Image textImage; //Audio private Image audioImage; //Picture private Image picImage; private Image jpgImage; //Video private Image sgpImage; private Image aviImage; private Image wmvImage; private Image mpgImage; //Web private Image zipImage; private Image htmlImage; private Image xmlImage; //Source private Image cImage; private Image cppImage; private Image headerImage; //圖標管理容器 private Hashtable iconTable; //------------------------------------------------------------------------- public IconHelper() { iconTable = new Hashtable(); try { //載入圖標資源 imgFolder = Image.createImage("/filetype/folder.png"); unknownImage = Image.createImage("/filetype/unknown.png"); textImage = Image.createImage("/filetype/text.png"); //Audio audioImage = Image.createImage("/filetype/audio.png"); //Picture picImage = Image.createImage("/filetype/pic.png"); jpgImage = Image.createImage("/filetype/jpg.png"); //Video sgpImage = Image.createImage("/filetype/3gp.png"); aviImage = Image.createImage("/filetype/avi.png"); wmvImage = Image.createImage("/filetype/wmv.png"); mpgImage = Image.createImage("/filetype/mpg.png"); //Web zipImage = Image.createImage("/filetype/zip.png"); htmlImage = Image.createImage("/filetype/html.png"); xmlImage = Image.createImage("/filetype/xml.png"); //Source cImage = Image.createImage("/filetype/c.png"); cppImage = Image.createImage("/filetype/cpp.png"); headerImage = Image.createImage("/filetype/header.png"); } catch (IOException e) { //圖標資源 imgFolder = null; unknownImage = null; textImage = null; //Audio audioImage = null; //Picture picImage = null; jpgImage = null; //Video sgpImage = null; aviImage = null; wmvImage = null; mpgImage = null; //Web zipImage = null; htmlImage = null; xmlImage = null; //Source cImage = null; cppImage = null; headerImage = null; e.printStackTrace(); } initTable(); } //------------------------------------------------------------------------- private void initTable() { //Key爲擴展名（不包括'.'符號），值爲content type iconTable.put("/", imgFolder); iconTable.put("", unknownImage); iconTable.put("txt", textImage); //Source iconTable.put("c", cImage); iconTable.put("cpp", cppImage); iconTable.put("h", headerImage); //Web iconTable.put("html", htmlImage); iconTable.put("htm", htmlImage); iconTable.put("xml", xmlImage); iconTable.put("zip", zipImage); iconTable.put("jar", zipImage); //Video iconTable.put("mp3", audioImage); iconTable.put("wma", audioImage); iconTable.put("mid", audioImage); iconTable.put("wav", audioImage); //Picture iconTable.put("gif", picImage); iconTable.put("png", picImage); iconTable.put("jpg", jpgImage); iconTable.put("jepg", jpgImage); //Video iconTable.put("3gp", sgpImage); iconTable.put("avi", aviImage); iconTable.put("wmv", wmvImage); iconTable.put("mpeg", mpgImage); iconTable.put("mpg", mpgImage); iconTable.put("mp4", mpgImage); } //------------------------------------------------------------------------- //按照擴展名（不包括'.'符號）獲取文件的圖標對象 public Image getIconByExt(final String extension) { Image temp = (Image)iconTable.get(extension); //是否爲空，則使用默認圖標替代 return( (temp == null) ? unknownImage : temp); } //------------------------------------------------------------------------- }

 

MainPanel主面板，顯示文件、文件夾列表，瀏覽文件：

/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package main; import com.sun.lwuit.Button; import com.sun.lwuit.Command; import com.sun.lwuit.Component; import com.sun.lwuit.Container; import com.sun.lwuit.Dialog; import com.sun.lwuit.Form; import com.sun.lwuit.Image; import com.sun.lwuit.Label; import com.sun.lwuit.List; import com.sun.lwuit.TextArea; import com.sun.lwuit.events.ActionEvent; import com.sun.lwuit.events.ActionListener; import com.sun.lwuit.layouts.BorderLayout; import com.sun.lwuit.list.ListCellRenderer; import com.sun.lwuit.plaf.Border; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.InputStream; import java.util.Enumeration; import java.util.Vector; import javax.microedition.io.Connector; import javax.microedition.io.file.FileConnection; import javax.microedition.io.file.FileSystemRegistry; /** * * @author Sunny */ public class MainPanel implements ActionListener { //常量定義 private final String UP_DIR = ".."; private final String SEPS_STR = "/"; private final int SEPS_CHAR = '/'; private final String ROOT = "/"; private final String RES_PREFIX = "file://"; private final int BLOCK_SIZE = 256; //擴展名 private final String TEXT_EXT[] = {".TXT", ".H", ".HPP", ".C", ".CPP", ".INC"}; private final String IMAGE_EXT[] = {".JPG", ".JPEG", ".PNG", ".GIF"}; private final String WEB_EXT[] = {".HTM", ".HTML", ".XML", ".CSS"}; //字符編碼 private final String CHARACTER_CODE = "UTF-8"; //主MIDlet private MainMIDlet let = null; //主界面 private Form listForm = null; //內容列表 private List contentList = null; //顯示文件用窗體 private Form textForm = null; //裝載文本項目用 private TextArea text = null; //顯示圖片用的窗體 private Form imageForm = null; //命令 private Command cmdExit = null;//退出程序 private Command cmdView = null;//瀏覽目錄/文件 private Command cmdDone = null;//退出瀏覽文件內容 //圖標幫助類 private IconHelper helper = null; //當前目錄路徑 private String currentDir = null; public MainPanel(MainMIDlet __let) { let = __let; //初始化當前目錄爲根目錄 currentDir = ROOT; //初始化圖標幫助實例 helper = new IconHelper(); listForm = new Form(""); listForm.setLayout(new BorderLayout()); //主顯示爲List // contentList = new List(); // contentList.setListCellRenderer(new MyRenderer()); // listForm.addComponent(BorderLayout.CENTER, contentList); //文本顯示窗體 textForm = new Form(""); //文本裝載項目 text = new TextArea(); text.setWidestChar('一'); //圖像顯示窗體 imageForm = new Form(""); //創建命令 cmdExit = new Command("退出"); cmdView = new Command("瀏覽"); cmdDone = new Command("返回"); //添加命令綁定 listForm.addCommand(cmdExit); listForm.addCommand(cmdView); listForm.addCommandListener(this); //添加文字處理框 textForm.setLayout(new BorderLayout()); textForm.addComponent(BorderLayout.CENTER, text); //設置文本瀏覽器窗體的綁定命令 textForm.addCommand(cmdDone); textForm.addCommandListener(this); //設置圖像瀏覽窗體的命令綁定 imageForm.addCommand(cmdDone); imageForm.addCommandListener(this); //初始化顯示 new BrowseThread(currentDir, true).start(); } class MyContainer extends Container { private Label name; public MyContainer(String source) { name = new Label(source); name.getStyle().setBgTransparency(0); addComponent(name); } } class MyRenderer implements ListCellRenderer { private Label focus; public MyRenderer() { focus = new Label(); Border b = Border.createLineBorder(1, 0xff0000); focus.getStyle().setBorder(b); } public Component getListCellRendererComponent(List list, Object value, int index, boolean selected) { return (MyContainer) value; } public Component getListFocusComponent(List list) { return focus; } } public void actionPerformed(ActionEvent evt) { Command c = evt.getCommand(); if (c == cmdExit) { let.exit(); } else if (c == cmdView) {//查看命令 //當前列表中沒有目錄項 if (contentList.size() == 0) { //啓動線程來瀏覽指定目錄 new BrowseThread(ROOT, true).start(); } else { final String url = ((MyContainer) contentList.getSelectedItem()).name.getText(); if (url.endsWith(SEPS_STR) == true) {//當前項目爲目錄，則顯示其子項目 //啓動瀏覽線程來瀏覽指定目錄 new BrowseThread(currentDir + url, true).start(); } else if (url.endsWith(UP_DIR) == true) {//當前項目爲父目錄，則需要回退 backward(); } else {//當前項目爲文件 //啓動瀏覽線程來瀏覽指定文件 new BrowseThread(currentDir + url, false).start(); } } } else if (c == cmdDone) {//關閉文本閱讀，返回目錄瀏覽 //啓動瀏覽線程來瀏覽指定文件 new BrowseThread(currentDir, true).start(); } } //------------------------------------------------------------------------- //回退瀏覽當前目錄的父目錄內容 private void backward() { //獲取當前目錄的父目錄名稱 int pos = currentDir.lastIndexOf(SEPS_CHAR, currentDir.length() - 2); if (pos != -1) { //存在上層目錄 currentDir = currentDir.substring(0, pos + 1); } else { //不存在上層目錄即根目錄 currentDir = ROOT; } //啓動瀏覽線程來瀏覽指定目錄 new BrowseThread(currentDir, true).start(); } class BrowseThread extends Thread { private String url = null; private boolean isDirectory = false; public BrowseThread(final String __url, final boolean __isDirectory) { url = __url; isDirectory = __isDirectory; } public void run() { //瀏覽目錄或文件 if (isDirectory) { text.setText(""); imageForm.removeAll(); showDir(url); } else { showFile(url); } } //顯示指定目錄 public void showDir(final String dir) { //設置列表title Enumeration em = null; FileConnection fc = null; //設置當前目錄 currentDir = dir; //初始化列表 listForm.removeAll(); contentList = new List(); contentList.setListCellRenderer(new MyRenderer()); listForm.addComponent(BorderLayout.CENTER, contentList); try { if (dir.equals(ROOT) == true) { //枚舉根目錄列表 em = FileSystemRegistry.listRoots(); } else {//非根目錄 fc = (FileConnection) Connector.open(RES_PREFIX + dir); em = fc.list(); //添加上層根目錄 MyContainer up = new MyContainer(UP_DIR); up.name.setIcon(helper.getIconByExt("/")); contentList.addItem(up); } while (em.hasMoreElements()) { String fileName = (String) em.nextElement(); if (fileName.endsWith(SEPS_STR)) {//如果爲目錄 //v.addElement(fileName); MyContainer c = new MyContainer(fileName); c.name.setIcon(helper.getIconByExt("/")); contentList.addItem(c); System.out.println(fileName); System.out.println("It's OK!"); } else {//非目錄（文件） MyContainer c = new MyContainer(fileName); c.name.setIcon(helper.getIconByExt(extractExt(fileName))); contentList.addItem(c); } } listForm.revalidate(); //初始化選擇 contentList.setSelectedIndex(0, true); //關閉文件連接 if (fc != null) { fc.close(); } } catch (Exception ex) { ex.printStackTrace(); } listForm.show(); } //--------------------------------------------------------------------- //顯示指定文件內容 private void showFile(final String fileName) { //Dialog.show(RES_PREFIX, fileName, "ok", "cancel"); String tempFileName = fileName.toUpperCase(); try { FileConnection fc = (FileConnection) Connector.open(RES_PREFIX + fileName); if (isEndWithIn(tempFileName, IMAGE_EXT) == true) {//圖片文件 //創建流 InputStream is = fc.openInputStream(); Image img = Image.createImage(is); //設置圖片窗體Title imageForm.setTitle(getRelativeName(fileName)); imageForm.setLayout(new BorderLayout()); imageForm.removeAll(); Button b = new Button(img); imageForm.addComponent(BorderLayout.CENTER, b); //關閉流 is.close(); //關閉文件連接 fc.close(); imageForm.show(); } else {//文本文件 int rawFileSize = (int) (fc.fileSize()); int fileSize = ((rawFileSize / BLOCK_SIZE) + 1) * BLOCK_SIZE; //依據文件內容設置title textForm.setTitle(getRelativeName(fileName) + ", " + rawFileSize + "/" + fileSize); DataInputStream dis = fc.openDataInputStream(); byte[] buffer = new byte[rawFileSize]; //讀取文件內容 dis.readFully(buffer); textForm.setLayout(new BorderLayout()); textForm.removeAll(); text.setText(new String(buffer, "UTF-8")); textForm.addComponent(BorderLayout.CENTER, text); //關閉流 dis.close(); //關閉文件連接 fc.close(); textForm.show(); } } catch (Exception ex) { ex.printStackTrace(); } } //------------------------------------------------------------------------- //指定文件名稱是否以數組中內容結尾 private boolean isEndWithIn(final String fileName, final String[] extArray) { for (int i = 0; i < extArray.length; ++i) { if (fileName.endsWith(extArray[i]) == true) { return (true); } } return (false); } //------------------------------------------------------------------------- //從完整文件名中提取相對文件名 private String getRelativeName(final String fileName) { int pos = fileName.lastIndexOf(SEPS_CHAR); if (pos == -1) { return (""); } return (fileName.substring(pos + 1, fileName.length())); } //------------------------------------------------------------------------- //獲取擴展名（不包括'.'符號） private String extractExt(final String fileName) { int pos = fileName.lastIndexOf('.'); return (fileName.substring(pos + 1, fileName.length()).toLowerCase()); } //--------------------------------------------------------------------- } }

 

MIDlet啓動類：
/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package main; import com.sun.lwuit.Display; import javax.microedition.midlet.*; /** * @author Sunny */ public class MainMIDlet extends MIDlet { //主顯示面板 private MainPanel panel = null; public void startApp() { Display.init(this); panel = new MainPanel(this); } public void pauseApp() { } public void destroyApp(boolean unconditional) { } public void exit(){ destroyApp(false); notifyDestroyed(); } }