manager.java

有关j2me的很好的例子可以研究一下

     * @return icon image
     */
    private static Image getSingleSuiteIcon() {
        if (singleSuiteIcon != null) {
            return singleSuiteIcon;
        }

        singleSuiteIcon = getIconFromStorage(
                        (colorDisplay ? "_single8.png" : "_single2.png"));
        return singleSuiteIcon;
    }

    /**
     * Gets an icon from storage.
     *
     * @param iconName name without a path
     * @return icon image
     */
    private static Image getIconFromStorage(String iconName) {
        String iconFilename;
        RandomAccessStream stream;
        byte[] rawPng;

        iconFilename = File.getStorageRoot() + iconName;
        stream = new RandomAccessStream(classSecurityDomain);
        try { 
            stream.connect(iconFilename, Connector.READ);
            rawPng = new byte[stream.getSizeOf()];
            stream.readBytes(rawPng, 0, rawPng.length);
            stream.disconnect();
            return Image.createImage(rawPng, 0, rawPng.length);
        } catch (java.io.IOException noImage) {
        }

        return null;
    }

    /**
     * Create and initialize a new Manager MIDlet.
     * The Display is retreived and the list of MIDlets read
     * from the descriptor file.
     */
    public Manager() {
        installer = Installer.getInstaller(classSecurityDomain);
        display = Display.getDisplay(this);
        colorDisplay = display.isColor();
        mcount = 0;
        minfo = new MIDletSuiteInfo[20];
        readMIDletSuiteInfo();
        restoreSettings();
    }

    /**
     * Start puts up a List of the MIDlets found in the descriptor file.
     */
    public void startApp() {
        setupList();

        if (mcount > 0) {
            mlist.addCommand(launchCmd);
            mlist.addCommand(infoCmd);
            mlist.addCommand(removeCmd);
            mlist.addCommand(updateCmd);
        }

        mlist.addCommand(installCmd);
        mlist.addCommand(settingsCmd);
        mlist.addCommand(aboutCmd);
        mlist.setCommandListener(this); // Listen for the selection

        if (first) {
            first = false;
            Alert splash = new Alert(null);
            if (display.numColors() > 2) {
                splash.setImage(getIconFromStorage((colorDisplay ?
                    "_logo_8.png" : "_logo_2.png")));
            }

            splash.setString(SMALL_COPYRIGHT);
            display.setCurrent(splash, mlist);
        } else {
            display.setCurrent(mlist);
        }
    }

    /**
     * Pause; there are no resources that need to be released.
     */
    public void pauseApp() {
    }

    /**
     * Destroy cleans up.
     *
     * @param unconditional is ignored; this object always
     * destroys itself when requested.
     */
    public void destroyApp(boolean unconditional) {
        /*
         * The backgroundInstaller could be waiting for an update of the 
         * install state.
         */
        cancelBackgroundInstall();
    }

    /**
     * Respond to a command issued on any Screen.
     * The commands on list is Select and About.
     * Select triggers the creation of the MIDlet of the same name.
     * About puts up the copyright notice.
     *
     * @param c command activiated by the user
     * @param s the Displayable the command was on.
     */
    public void commandAction(Command c, Displayable s) {
        if ((s == mlist && c == List.SELECT_COMMAND) || (c == launchCmd)) {
            launchSuite(minfo[mlist.getSelectedIndex()]);
        } else if (c == infoCmd) {
            displaySuiteInfo(minfo[mlist.getSelectedIndex()]);
        } else if (c == removeCmd) {
            // save the selected suite for the removeOk command
            selectedSuite = mlist.getSelectedIndex();
            confirmRemove(minfo[selectedSuite]);
        } else if (c == removeOkCmd) {
            removeSuite(minfo[selectedSuite]);
        } else if (c == updateCmd) {
            updateSuite(minfo[mlist.getSelectedIndex()]);
        } else if (s == mlist && c == installCmd) {
            // user wants a list of suites to install
            getUrl();
        } else if (c == selectSuiteCmd) {
            // user wants to select a suite to install
            selectSuiteToInstall(urlTextBox.getString());
        } else if (s == installListBox &&
                  (c == List.SELECT_COMMAND || c == installCmd)) {
            // the user has selected a suite
            installSuite(installListBox.getSelectedIndex());
        } else if (c == nextCmd) {
            // the user has entered a username and password
            resumeInstallWithPassword();
        } else if (c == okCmd) {
            resumeInstallAfterWarning();
        } else if (c == settingsCmd) {
            getSettings();
        } else if (c == saveSettingsCmd) {
            saveSettings();
        } else if (c == aboutCmd) {
            Alert a = new Alert(Resource.getString("About Wireless Profile"));
            a.setString(COPYRIGHT);
            display.setCurrent(a, mlist);
        } else if (c == stopCmd) {
            if (installer != null) {
                /*
                 * backgroundInstaller may be displaying
                 * the "Finishing" message
                 */
                if (installer.stopInstalling()) {
                    displayCancelledMessage(cancelledMessage);
                }
            } else {
                display.setCurrent(mlist);
            }
        } else if (c == cancelInstallCmd) {
            cancelBackgroundInstall();
        } else if (c == backCmd || c == cancelCmd) {
            // goto back to the main list of suites
            display.setCurrent(mlist);
        }
    }

    /**
     * Lauches a suite.
     *
     * @param suiteInfo information for suite to launch
     */
    private void launchSuite(MIDletSuiteInfo suiteInfo) {
        try {
            // Create an instance of the MIDlet class
            // All other initialization happens in MIDlet constructor
            if (installer.execute(suiteInfo.storageName,
                                  suiteInfo.displayName)) {
                /*
                 * Give the new MIDlet the screen by destroy our self,
                 * because we are running in a limited VM and must
                 * restart the VM let the select suite run.
                 */
                destroyApp(false);
                notifyDestroyed();
            } else {
                // Give the new MIDlet the screen by pausing and
                // asking to be resumed.
                notifyPaused();
                resumeRequest();
            }
        } catch (Exception ex) {
            StringBuffer sb = new StringBuffer()
                .append(suiteInfo.displayName)
                .append("\n")
                .append(Resource.getString("Error"))
                .append(ex.toString());

            Alert a = new Alert(Resource.getString("Cannot start: "), 
                                sb.toString(), null, AlertType.ERROR);
            a.setTimeout(Alert.FOREVER);
            display.setCurrent(a, mlist);
        }
    }

    /**
     * Display the information for a suite.
     *
     * @param suiteInfo information for suite to display
     */
    private void displaySuiteInfo(MIDletSuiteInfo suiteInfo) {
        Form infoForm;
        String name;
        Image icon;

        try {
            infoForm = new Form(null);

            if (suiteInfo.singleMidlet) {
                name = suiteInfo.displayName;
                icon = suiteInfo.icon;
            } else {
                name = suiteInfo.midletSuite.getProperty(
                          Installer.SUITE_NAME_PROP);
                icon = getSuiteIcon();
            }

            infoForm.setTitle(Resource.getString("Info") + ": " + name);

            infoForm.append(
                new ImageItem(null, icon, ImageItem.LAYOUT_NEWLINE_BEFORE +
                              ImageItem.LAYOUT_CENTER +
                              ImageItem.LAYOUT_NEWLINE_AFTER, null));

            // round up the size to a Kilobyte
            infoForm.append(Resource.getString("Size"));
            infoForm.append(": ");
            infoForm.append(
                Integer.toString((suiteInfo.midletSuite.getStorageUsed() +
                    1023) / 1024));
            infoForm.append(" K");
            infoForm.append("\n");

            infoForm.append(Resource.getString("Version"));
            infoForm.append(": ");
            infoForm.append(
                suiteInfo.midletSuite.getProperty(Installer.VERSION_PROP));
            infoForm.append("\n");

            infoForm.append(Resource.getString("Vendor"));
            infoForm.append(": ");
            infoForm.append(
                suiteInfo.midletSuite.getProperty(Installer.VENDOR_PROP));
            infoForm.append("\n");

            if (!suiteInfo.singleMidlet) {
                infoForm.append(Resource.getString("Contents"));
                infoForm.append(": ");
                infoForm.append("\n");
                appendMIDletsToForm(suiteInfo.midletSuite, infoForm);
            }

            infoForm.append(Resource.getString("Website"));
            infoForm.append(": ");
            infoForm.append(suiteInfo.midletSuite.getJadUrl());
        } catch (Exception ex) {
            StringBuffer sb = new StringBuffer()
                .append(suiteInfo.displayName)
                .append("\n")
                .append(Resource.getString("Exception"))
                .append(": ")
                .append(ex.toString());

            Alert a = new Alert(Resource.getString("Cannot access: "), 
                                sb.toString(), null, AlertType.ERROR);
            a.setTimeout(Alert.FOREVER);
            display.setCurrent(a, mlist);
            return;
        }

        infoForm.addCommand(backCmd);
        infoForm.setCommandListener(this);
        display.setCurrent(infoForm);
    }

    /**
     * Confirm the removal of a suite.
     *
     * @param suiteInfo information for suite to remove
     */
    private void confirmRemove(MIDletSuiteInfo suiteInfo) {
        Form confirmForm;
        String extraConfirmMsg;

        try {
            confirmForm = new Form(null);

            confirmForm.setTitle(Resource.getString("Confirmation"));

            confirmForm.append(Resource.getString(
                "Are you sure you want to remove "));
            confirmForm.append("\"");

            if (suiteInfo.singleMidlet) {
                confirmForm.append(suiteInfo.displayName);
            } else {
                confirmForm.append(suiteInfo.midletSuite.getProperty(
                                   Installer.SUITE_NAME_PROP));
            }

            confirmForm.append("\"?");
            confirmForm.append("\n");
            confirmForm.append("\n");

            extraConfirmMsg = 
                suiteInfo.midletSuite.getProperty("MIDlet-delete-confirm");
            if (extraConfirmMsg != null) {
                confirmForm.append(extraConfirmMsg);
                confirmForm.append("\n");
                confirmForm.append("\n");
            }

            if (!suiteInfo.singleMidlet) {
                confirmForm.append(Resource.getString("This suite contains"));
                confirmForm.append(": ");
                confirmForm.append("\n");
                appendMIDletsToForm(suiteInfo.midletSuite, confirmForm);
                confirmForm.append("\n");
            }

            confirmForm.append(Resource.getString(
                "Removing will erase all data and cannot be undone."));
        } catch (Exception ex) {
            StringBuffer sb = new StringBuffer()
                .append(suiteInfo.displayName)
                .append("\n")
                .append(Resource.getString("Exception"))
                .append(": ")
                .append(ex.toString());

            Alert a = new Alert(Resource.getString("Cannot access: "), 
                                sb.toString(), null, AlertType.ERROR);
            a.setTimeout(Alert.FOREVER);
            display.setCurrent(a, mlist);
            return;
        }

        confirmForm.addCommand(cancelCmd);
        confirmForm.addCommand(removeOkCmd);
        confirmForm.setCommandListener(this);
        display.setCurrent(confirmForm);
    }

    /**
     * Remove a suite.
     *
     * @param suiteInfo information for suite to remove
     */
    private void removeSuite(MIDletSuiteInfo suiteInfo) {
        installer.remove(suiteInfo.storageName);
        destroyApp(false);
        notifyDestroyed();
    }

    /**
     * Update a suite.
     *
     * @param suiteInfo information for suite to update
     */
    private void updateSuite(MIDletSuiteInfo suiteInfo) {
        String name;

        if (suiteInfo.singleMidlet) {
            name = suiteInfo.displayName;
        } else {
            name = 
                suiteInfo.midletSuite.getProperty(Installer.SUITE_NAME_PROP);
        }

        cancelledMessage = Resource.getString("Update cancelled.");
        finishingMessage = Resource.getString("Finishing update.");
        installSuiteCommon("Updating", name,
            suiteInfo.midletSuite.getJadUrl(),
            name + Resource.getString(" was successfully updated"),
            true);