如何在Blackberry应用程序中设置备用入口点？

Question

How to setup alternate entrypoint in Blackberry Application.There will be 2 application

1. UI Application
2. Background Application: will run on autostart.

There is a blackberry knowledge center article about this, which I tried, and coded as follows. But on clicking the application icon, there is no response.

class EntryPointForApplication extends UiApplication {
    public EntryPointForApplication() { 
        GUIApplication scr = new GUIApplication(); 
        pushScreen(scr);         
    } 

    public static void main(String[] args) { 

        if ( args != null && args.length > 0 && args[0].equals("background1") ){
            // Keep this instance around for rendering
            // Notification dialogs.
            BackgroundApplication backApp=new BackgroundApplication();
            backApp.enterEventDispatcher();
            backApp.setupBackgroundApplication();   

       } else {       
        // Start a new app instance for GUI operations.     
         EntryPointForApplication application = new EntryPointForApplication(); 
           application.enterEventDispatcher();         
       }        
    }   
}

Class UI Application

class GUIApplication extends MainScreen {   
    public GUIApplication(){        
        add(new LabelField("Hello World"));             
    } 
}

Background Application

class BackgroundApplication extends Application {   
    public BackgroundApplication() {
        // TODO Auto-generated constructor stub
    }
    public void setupBackgroundApplication(){

    }   
}

I configured Blackberry_App_Discriptor.xml according to this (edit) bad-link
Can any body help,where am going wrong.

Answer 1

Try logging the value of args and (if not null) args[0] to see what's actually being passed into main(). It's likely a problem with your compilation process where the background module is not passing an argument (or not passing the correct value).

Also, try saving off your EntryPointForApplication instance into a static variable so that it maintains a reference (isn't garbage collected) and so that if the icon is clicked again from the home screen while it's already running, you don't start multiple instances of your app. For example:

class EntryPointForApplication extends UiApplication {

    private static EntryPointForApplication theApp;

    public EntryPointForApplication() { 
        GUIApplication scr = new GUIApplication(); 
        pushScreen(scr);         
    } 

    public static void main(String[] args) { 

        if ( args != null && args.length > 0 && args[0].equals("background1") ){
            // Keep this instance around for rendering
            // Notification dialogs.
            BackgroundApplication backApp=new BackgroundApplication();
            backApp.setupBackgroundApplication();   
            backApp.enterEventDispatcher();
       } else {       
         if (theApp == null) {
             // Start a new app instance for GUI operations.     
             theApp = new EntryPointForApplication();
             theApp.enterEventDispatcher();         
         } 
       }        
    }   
}