java - RMS 存储的值在 J2ME 模拟器中不是永久可用的

Question

我有在 J2ME 中使用 RMS 存储值的代码。在模拟器上运行良好。所以，我的第一个问题是

当我重新启动模拟器时，所有存储的值都被删除。

存储的值显示在模拟器中，但没有显示在我正在测试我的应用程序的移动设备中。

我正在使用 NetBeans 来开发我的 J2ME 应用程序。

===更新===

/*
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 * and open the template in the editor.
 */

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import javax.microedition.rms.*;

public class TryNew extends MIDlet implements CommandListener, ItemCommandListener {

    private RecordStore record;
    private StringItem registered;
    static final String REC_STORE = "SORT";
    //Button existUser;
    Display display = null;
    private Ticker ticker;
    Form form = null;
    Form form1 = null;
    TextField tb, tb1, tb2, tb3;
    ChoiceGroup operator = null;
    String str = null;
    Command backCommand = new Command("Back", Command.BACK, 0);
    Command loginCommand = new Command("Login", Command.OK, 2);
    Command saveCommand = new Command("Save New", Command.OK, 1);
    Command sendCommand = new Command("Send", Command.OK, 2);
    Command selectCommand = new Command("Select", Command.OK, 0);
    Command exitCommand = new Command("Exit", Command.STOP, 3);
    private ValidateLogin ValidateLogin;

    public TryNew() {
    }

    public void startApp() throws MIDletStateChangeException {
        display = Display.getDisplay(this);
        form = new Form("Login");
        registered = new StringItem("", "Registered ?", StringItem.BUTTON);
        form1 = new Form("Home");
        tb = new TextField("Login Id: ", "", 10, TextField.PHONENUMBER);//TextField.PHONENUMBER
        tb1 = new TextField("Password: ", "", 30, TextField.PASSWORD);
        operator = new ChoiceGroup("Select Website", Choice.POPUP, new String[]{"Game", "Joke", "SMS"}, null);
        form.append(tb);
        form.append(tb1);
        form.append(operator);
        form.append(registered);
        registered.setDefaultCommand(selectCommand);
        registered.setItemCommandListener(this);
        form.addCommand(saveCommand);
        ticker = new Ticker("Welcome Screen");
        form.addCommand(loginCommand);
        form.addCommand(selectCommand);
        form.addCommand(exitCommand);
        //   existUser = new StringItem(null, "Registered ?");
        // form.append(existUser);
        form.setCommandListener(this);
        form1.addCommand(exitCommand);
        form1.addCommand(sendCommand);
        form1.setCommandListener(this);
        form.setTicker(ticker);
        display.setCurrent(form);
    }

    public void pauseApp() {
    }

    public void destroyApp(boolean unconditional) {
    }

    void showMessage(String message, Displayable displayable) {
        Alert alert = new Alert("");
        alert.setTitle("Error");
        alert.setString(message);
        alert.setType(AlertType.ERROR);
        alert.setTimeout(5000);
        display.setCurrent(alert, displayable);
    }

    public void commandAction(Command c, Displayable d) {
        if (c == exitCommand) {
            destroyApp(true);
            notifyDestroyed();
        } else if (c == backCommand) {
            display.setCurrent(form);
        } else if (c == loginCommand) {
            ValidateLogin = new ValidateLogin(this);
            ValidateLogin.start();
            ValidateLogin.validateLogin(tb.getString(), tb1.getString(), operator.getString(operator.getSelectedIndex()));
        } else if (c == saveCommand) {
            openRecord();
            writeRecord(tb.getString(), tb1.getString(), operator.getString(operator.getSelectedIndex()));
            closeRecord();
            showAlert("Login Credential Saved Successfully !!");
        } 
    }

    ////==============================================================================/////
    /// Record Management
    public void openRecord() {
        try {
            record = RecordStore.openRecordStore(REC_STORE, true);
        } catch (Exception e) {
            db(e.toString());
        }
    }

    public void closeRecord() {
        try {
            record.closeRecordStore();
        } catch (Exception e) {
            db(e.toString());
        }
    }

    public void deleteRecord() {
        if (RecordStore.listRecordStores() != null) {
            try {
                RecordStore.deleteRecordStore(REC_STORE);
            } catch (Exception e) {
                db(e.toString());
            }
        }
    }

    public void writeRecord(String login_id, String pwd, String operator_name) {
        String credential = login_id + "," + pwd + "," + operator_name;
        byte[] rec = credential.getBytes();
        try {
            if (login_id.length() > 10 || login_id.length() < 10) {
                showAlert("Please Enter valid Login Id");
            } else if (pwd.length() < 1) {
                showAlert("Please Password !!");
            } else {
                record.addRecord(rec, 0, rec.length);
            }

        } catch (Exception e) {
            db(e.toString());
        }
    }

    private void showAlert(String err) {
        Alert a = new Alert("");
        a.setString(err);
        a.setTimeout(Alert.FOREVER);
        display.setCurrent(a);
    }

    public void readRecord() {
        try {
            if (record.getNumRecords() > 0) {
                Comparator comp = new Comparator();
                RecordEnumeration re = record.enumerateRecords(null, comp, false);

                while (re.hasNextElement()) {
                    String str = new String(re.nextRecord());
                    showAlert(str);
                }
            }
        } catch (Exception e) {
            db(e.toString());
        }
    }

    private void db(String error) {
        System.err.println("Exception: " + error);
    }

    public void commandAction(Command c, Item item) {
        if (c == selectCommand && item == registered) {
            openRecord();
            readRecord();
            closeRecord();
        }
    }

    class Comparator implements RecordComparator {

        public int compare(byte[] rec1, byte[] rec2) {
            String str1 = new String(rec1);
            String str2 = new String(rec2);
            int result = str1.compareTo(str2);
            if (result == 0) {
                return RecordComparator.EQUIVALENT;
            } else if (result < 0) {
                return RecordComparator.PRECEDES;
            } else {
                return RecordComparator.FOLLOWS;
            }
        }
    }

    class ValidateLogin implements Runnable {

        TryNew midlet;
        private Display display;
        String login_id;
        String pwd;
        String operator_name;

        public ValidateLogin(TryNew midlet) {
            this.midlet = midlet;
            display = Display.getDisplay(midlet);
        }

        public void start() {
            Thread t = new Thread(this);
            t.start();
        }

        public void run() {
            if (login_id.length() > 10 || login_id.length() < 10) {
                showAlert("Please Enter valid Login Id");
            } else if (pwd.length() < 1) {
                showAlert("Please Password !!");
            } else {
                showHome();
            }
        }
        /* This method takes input from user like text and pass
        to servlet */

        public void validateLogin(String login_id, String pwd, String operator_name) {
            this.login_id = login_id;
            this.pwd = pwd;
            this.operator_name = operator_name;
        }

        /* Display Error On screen*/
        private void showAlert(String err) {
            Alert a = new Alert("");
            a.setString(err);
            a.setTimeout(Alert.FOREVER);
            display.setCurrent(a);
        }

        private void showHome() {
            tb2 = new TextField("To: ", "", 30, TextField.PHONENUMBER);
            tb3 = new TextField("Message: ", "", 300, TextField.ANY);
            form1.append(tb2);
            form1.append(tb3);
            form1.addCommand(loginCommand);
            //display.setCurrent(tb3);
            display.setCurrent(form1);

        }
    };
}

这就是我得到的，当我点击 Manage Emulator 时

Answer 1

您需要修复 storage_root您在 WTK 中的应用程序，

每当您启动 enulator 时，它都会引用相同的 storage_root，默认情况下，它会为每个 session 创建不同的数据文件