Location MIDlet closed after 110th orientation call in S60 5th Edition

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#exception #nokia #import #thread #terminal #string

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本文介绍了一个在S60第5版设备上使用Orientation.getOrientation()方法的问题，在第110次调用后可能导致MIDlet应用非正常关闭。通过提供示例代码展示了如何复现该问题。

ID	KIJ001579	Creation date	April 23, 2010
Platform	S60 5th Edition	Devices	Nokia N97, Nokia N97 mini
Category	Java ME	Subcategory	Location API (JSR-179)

Keywords (APIs, classes, methods, functions): Orientation.getOrientation()

Description

Orientation.getOrientation() returns the terminal's current orientation. This information can be retrieved from Nokia devices equipped with built-in magnetometer hardware.

On S60 5th Edition devices, heavy usage of Orientation.getOrientation() results in the location MIDlet closing either without an exception or with java.lang.OutOfMemoryError. The closing happens right after the 110th method call.

How to reproduce

1. Implement a test MIDlet by using the following code:

import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.location.LocationException;
import javax.microedition.location.Orientation;
import javax.microedition.midlet.*;

public class LocationTest extends MIDlet {

    Display d;
    Form f;
    boolean running = false;
    Thread t = null;
    protected int interval = 1000;

    public LocationTest() {

            d=Display.getDisplay(this);
            f=new Form("Location Test");
            startRequesting();
            }

    public void startApp() {
        d.setCurrent(f);
    }

    public void show(String s) {
        f.append(s);
    }

    //Implement the orientation updating activity within a thread
    public void startRequesting() {
        t = new Thread(new Runnable() {

            public void run() {
                running = true;
                try {
                    while (running) {
                        updateOrientation();
                        Thread.sleep(interval);
                    }
                } catch (InterruptedException ex) {
                    show("Exception: "+ex.toString());
                }
            }
        });
        t.start();
    }

    int num = 0;
    private void updateOrientation() {

        Orientation o;
        String s;
        try {
            f.deleteAll();
            o = Orientation.getOrientation();
           show("Orientation.getOrientation(): "+num);
            num++;

        }
         catch (LocationException ex) {

             show("Exception: " +ex.toString());

         }

    }

    public void pauseApp() {
    }

    public void destroyApp(boolean unconditional) {
    }
}