filebrowser.java

基于手机的通信录、文件、图片读写开发,j2me开发架构

/*
 * @(#)FileBrowser.java	1.10 04/08/10
 *
 * Copyright (c) 2000-2004 Sun Microsystems, Inc. All rights reserved.
 * PROPRIETARY/CONFIDENTIAL
 * Use is subject to license terms
 */
package  PDAPDemo.src.example.fc;
import java.util.*;
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.io.file.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
 * Demonstration MIDlet for File Connection API. This MIDlet implements simple
 * file browser for the filesystem avaliable to the J2ME applications.
 *
 */
public class FileBrowser extends MIDlet implements CommandListener {

    private String currDirName;

    private Command view = new Command("View", Command.ITEM, 1);
    private Command creat = new Command("New", Command.ITEM, 2);
    private Command creatOK = new Command("OK", Command.OK, 1);
    private Command prop = new Command("Properties", Command.ITEM, 2);
    private Command back = new Command("Back", Command.BACK, 2);
    private Command exit = new Command("Exit", Command.EXIT, 3);
    private TextField   nameInput;  // Input field for new file name
    private ChoiceGroup typeInput;  // Input fiels for file type (regular/dir)

    private final static String[] attrList = { "Read", "Write", "Hidden" };
    private final static String[] typeList = { "Regular File", "Directory" };
    private final static String[] monthList = { "Jan", "Feb", "Mar", "Apr",
    "May", "Jun", "Jul", "Aug",
    "Sep", "Oct", "Nov", "Dec" };

    private Image dirIcon, fileIcon;
    private Image[] iconList;

    /* special string denotes upper directory */
    private final static String UP_DIRECTORY = "..";

    /* special string that denotes apper directory accessible by this browser.
     * this virtual directory contains all roots.
     */
    private final static String MEGA_ROOT = "/";

    /* separator string as defined by FC specification */
    private final static String SEP_STR = "/";

    /* separator character as defined by FC specification */
    private final static char   SEP = '/';

    public FileBrowser() {
        currDirName = MEGA_ROOT;
        try {
            dirIcon = Image.createImage("/icons/dir.png");
        } catch (IOException e) {
            dirIcon = null;
        }
        try {
            fileIcon = Image.createImage("/icons/file.png");
        } catch (IOException e) {
            fileIcon = null;
        }
        iconList = new Image[] { fileIcon, dirIcon };
    }

    public void startApp() {
        try {
            showCurrDir();
        } catch (SecurityException e) {
            Alert alert = new Alert("Error",
                "You are not authorized to access the restricted API",
                null, AlertType.ERROR);
            alert.setTimeout(Alert.FOREVER);
            Form form = new Form("Cannot access FileConnection");
            form.append(new StringItem(null,
                "You cannot run this MIDlet with the current permissions. "
                + "Sign the MIDlet suite, or run it in a different security domain"));
            form.addCommand(exit);
            form.setCommandListener(this);
            Display.getDisplay(this).setCurrent(alert, form);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void pauseApp() {
    }

    public void destroyApp(boolean cond) {
        notifyDestroyed();
    }

    public void commandAction(Command c, Displayable d) {
        if (c == view) {
            List curr = (List)d;
            final String currFile = curr.getString(curr.getSelectedIndex());
            new Thread(new Runnable() {
                public void run() {
                    if (currFile.endsWith(SEP_STR) || currFile.equals(UP_DIRECTORY)) {
                        traverseDirectory(currFile);
                    } else {
                        // Show file contents
                        showFile(currFile);
                    }
                }
            }).start();
        } else if (c == prop) {
            List curr = (List)d;
            String currFile = curr.getString(curr.getSelectedIndex());

            showProperties(currFile);
        } else if (c == creat) {
             createFile();
        } else if (c == creatOK) {
            String newName = nameInput.getString();
            if (newName == null || newName.equals("")) {
                Alert alert = new Alert("Error!",
                "File Name is empty. Please provide file name",
                null,
                AlertType.ERROR);
                alert.setTimeout(Alert.FOREVER);
                Display.getDisplay(this).setCurrent(alert);
            } else {
                // Create file in a separate thread and disable all commands
                // except for "exit"
                executeCreateFile(newName, typeInput.getSelectedIndex() != 0);
                Display.getDisplay(this).getCurrent().removeCommand(creatOK);
                Display.getDisplay(this).getCurrent().removeCommand(back);
            }

        } else if (c == back) {
            showCurrDir();
        } else if (c == exit) {
            destroyApp(false);
        }
    }


    //Starts creatFile with another Thread
    private void executeCreateFile(final String name, final boolean val) {
        new Thread(new Runnable(){
            public void run(){
                createFile(name, val);
            }
        }).start();
    }


    /**
     * Show file list in the current directory .
     */
    void showCurrDir() {
        Enumeration e;
        FileConnection currDir = null;
        List browser;
        try {
            if (MEGA_ROOT.equals(currDirName)) {
                e = FileSystemRegistry.listRoots();
                 browser = new List(currDirName, List.IMPLICIT);
            } else {
                currDir = (FileConnection)Connector.open("file://localhost/" +
                            currDirName);
                e = currDir.list();
                 browser = new List(currDirName, List.IMPLICIT);
                  // not root - draw UP_DIRECTORY
                 browser.append(UP_DIRECTORY, dirIcon);
            }

            while (e.hasMoreElements()) {
                String fileName = (String)e.nextElement();
                if (fileName.charAt(fileName.length()-1) == SEP) {
                    // This is directory
                    browser.append(fileName, dirIcon);
                } else {
                    // this is regular file
                    browser.append(fileName, fileIcon);
                }
            }

            browser.setSelectCommand(view);
            browser.addCommand(prop);
            //Do not allow creating files/directories beside root
            if (!MEGA_ROOT.equals(currDirName)) {
                browser.addCommand(creat);
            }
            browser.addCommand(exit);

            browser.setCommandListener(this);

            if (currDir != null) {
                currDir.close();
            }

            Display.getDisplay(this).setCurrent(browser);
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }

    void traverseDirectory(String fileName) {
    /* In case of directory just change the current directory
     * and show it
     */
        if (currDirName.equals(MEGA_ROOT)) {
            if (fileName.equals(UP_DIRECTORY)) {
                // can not go up from MEGA_ROOT
                return;
            }
            currDirName = fileName;
        } else if (fileName.equals(UP_DIRECTORY)) {
            // Go up one directory
            // TODO use setFileConnection when implemented
            int i = currDirName.lastIndexOf(SEP, currDirName.length()-2);
            if (i != -1) {
                currDirName = currDirName.substring(0, i+1);
            } else {
                currDirName = MEGA_ROOT;
            }
        } else {
            currDirName = currDirName + fileName;
        }
        showCurrDir();
    }

    void showFile(String fileName) {
        try {
            FileConnection fc = (FileConnection)
                Connector.open("file://localhost/" + currDirName + fileName);
            if (!fc.exists()) {
                throw new IOException("File does not exists");
            }

            InputStream fis = fc.openInputStream();
            byte[] b = new byte[1024];

            int length = fis.read(b, 0, 1024);

            fis.close();
            fc.close();

            TextBox viewer = new TextBox("View File: " + fileName, null, 1024,
            TextField.ANY | TextField.UNEDITABLE);

            viewer.addCommand(back);
            viewer.addCommand(exit);
            viewer.setCommandListener(this);

            if (length > 0) {
                viewer.setString(new String(b, 0, length));
            }

            Display.getDisplay(this).setCurrent(viewer);
        } catch (Exception e) {
            Alert alert = new Alert("Error!",
            "Can not access file " + fileName
            + " in directory " + currDirName
            + "\nException: " + e.getMessage(),
            null,
            AlertType.ERROR);
            alert.setTimeout(Alert.FOREVER);
            Display.getDisplay(this).setCurrent(alert);
        }

    }

    void showProperties(String fileName) {
        try {
            if (fileName.equals(UP_DIRECTORY)) {
                return;
            }

            FileConnection fc = (FileConnection)Connector.open("file://localhost/"
                                + currDirName + fileName);
            if (!fc.exists()) {
                throw new IOException("File does not exists");
            }

            Form props = new Form("Properties: " + fileName);
            ChoiceGroup attrs = new ChoiceGroup("Attributes:", Choice.MULTIPLE,
            attrList, null);

            attrs.setSelectedFlags(new boolean[] {fc.canRead(),
            fc.canWrite(),
            fc.isHidden()});

            props.append(new StringItem("Location:", currDirName));
            props.append(new StringItem("Type: ", fc.isDirectory() ?
            "Directory": "Regular File"));
            props.append(new StringItem("Modified:",myDate(fc.lastModified())));
            props.append(attrs);

            props.addCommand(back);
            props.addCommand(exit);
            props.setCommandListener(this);

            fc.close();

            Display.getDisplay(this).setCurrent(props);
        } catch (Exception e) {
            Alert alert = new Alert("Error!",
            "Can not access file " + fileName
            + " in directory " + currDirName
            + "\nException: " + e.getMessage(),
            null,
            AlertType.ERROR);
            alert.setTimeout(Alert.FOREVER);
            Display.getDisplay(this).setCurrent(alert);
        }
    }

    void createFile() {
        Form creator = new Form("New File");
        nameInput = new TextField("Enter Name", null, 256, TextField.ANY);
        typeInput = new ChoiceGroup("Enter File Type", Choice.EXCLUSIVE,
        typeList, iconList);
        creator.append(nameInput);
        creator.append(typeInput);
        creator.addCommand(creatOK);
        creator.addCommand(back);
        creator.addCommand(exit);
        creator.setCommandListener(this);
        Display.getDisplay(this).setCurrent(creator);
    }

    void createFile(String newName, boolean isDirectory) {

        try {
            FileConnection fc = (FileConnection) Connector.open("file:///" +
            currDirName +
            newName);
            if (isDirectory) {
                fc.mkdir();
            } else {
                fc.create();
            }
            showCurrDir();
        } catch (Exception e) {
            String s = "Can not create file '" + newName + "'";
            if (e.getMessage() != null && e.getMessage().length() > 0) {
                s += "\n" + e;
            }
            Alert alert = new Alert("Error!", s, null, AlertType.ERROR);
            alert.setTimeout(Alert.FOREVER);
            Display.getDisplay(this).setCurrent(alert);
            // Restore the commands that were removed in commandAction()
            Display.getDisplay(this).getCurrent().addCommand(creatOK);
            Display.getDisplay(this).getCurrent().addCommand(back);
        }
    }

    private String myDate(long time) {
        Calendar cal = Calendar.getInstance();

        cal.setTime(new Date(time));

        StringBuffer sb = new StringBuffer();

        sb.append(cal.get(Calendar.HOUR_OF_DAY));
        sb.append(':');
        sb.append(cal.get(Calendar.MINUTE));
        sb.append(':');
        sb.append(cal.get(Calendar.SECOND));
        sb.append(',');
        sb.append(' ');
        sb.append(cal.get(Calendar.DAY_OF_MONTH));
        sb.append(' ');
        sb.append(monthList[cal.get(Calendar.MONTH)]);
        sb.append(' ');
        sb.append(cal.get(Calendar.YEAR));

        return sb.toString();
    }
}