Enabling pauseApp() method calls in Java ME

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Article Metadata

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Code Example

Source file: Media:HelloMIDletSource.zip

Installation file: Media:HelloMIDletBinaries.zip

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Tested with

SDK: S60 SDK 3rd Edition FP2 v1.1

Devices(s): Nokia 6650, Nokia E52

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Compatibility

Platform(s): S60 3rd Edition, FP2

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Article

Keywords: MIDlet.pauseApp(), MIDlet.startApp(), Nokia-MIDlet-Background-Event and Nokia-MIDlet-Flip-Close JAD attributes

Created: jarmlaht (21 May 2008)

Reviewed: skalogir (20 Aug 2012)

Last edited: skalogir (20 Aug 2012)

Overview

This code snippet demonstrates how to enable MIDlet.pauseApp() method calls in MIDlets. There are some new JAD attributes in the S60 3rd Edition FP2 Java ME implementation, which can be used to enable this:

Nokia-MIDlet-Background-Event: pause

The system will call pauseApp for the MIDlet if the application is set to the background and if the value of the Nokia-MIDlet-Background-Event attribute is "pause". If the value is "run", or any other value than "pause", or no attribute or value is given, the pauseApp is not called.

Note: The startApp is called accordingly when the MIDlet is set again to the foreground.

Nokia-MIDlet-Flip-Close: pause

The system will call pauseApp() for the MIDlet if the device flip is closed and if the value of the Nokia-MIDlet-Flip-Close attribute is "pause". If the value is "run", or any other value than "pause", or no attribute or value is given, the pauseApp() is not called.

Note: The startApp() is called accordingly when the flip is opened again.

To test this, compile and run the following MIDlet. Make sure you have either of the two attributes in the JAD file. Put the MIDlet to the background and bring it to the foregroung again:

MIDlet-1: HelloMIDlet, , HelloMIDlet
MIDlet-Jar-Size: <your jar file size>
MIDlet-Jar-URL: HelloWorld.jar
MIDlet-Name: HelloWorld
MIDlet-Vendor: Nokia Developer
MIDlet-Version: 1.0
MicroEdition-Configuration: CLDC-1.1
MicroEdition-Profile: MIDP-2.0
Nokia-MIDlet-Background-Event: pause

Source

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
 
public class HelloMIDlet extends MIDlet implements CommandListener {
    private Form form;
    private Command exitCommand;
 
    public void startApp() {
        if (form == null) { // Create the Form and Command only once
            form = new Form("HelloMIDlet");
            exitCommand = new Command("Exit", Command.EXIT, 1);
            form.addCommand(exitCommand);
            form.setCommandListener(this);
        }
        Display.getDisplay(this).setCurrent(form);
        form.append("startApp()\n");
    }
 
    public void pauseApp() {
        form.append("pauseApp()\n");        
    }
 
    public void destroyApp(boolean unconditional) {
    }
 
    public void commandAction(Command c, Displayable d) {
        if (c == exitCommand) this.notifyDestroyed();
    }
}

Postconditions

When the MIDlet is once put to the background and brought back to the foreground, the text "startApp() pauseApp() startApp()" should be on the Form.

See also

JAD and JAR manifest attributes

How to handle MIDlet sent to the background