Question

I want to create a simple Blackberry app that plays an audio file whenever I charge my phone, and for the application to close when I unplug it.

Pseudocode

1. Start application when battery cable plugged in,

2. application plays sound continuously while charging

   could not make it loop without a gap of silence in between, instead play a sound

3. if user unplugs cable, stop the stream, play a sound, stop the stream

4. optional: if battery level falls to critical/done charging, play a sound

Looking through the docs I think there isn’t a listener to tell you if battery is at 100%.

Edit: Found a way through batteryStatusChange, and thanks Nate for helping me out there

Having null exception errors.

Edit: Used InputStream and no more null exception errors. Added wav files to the res folder. New code below plays a sound at 100 and two different sounds, one for USB connect and another for USB disconnect.

public class HelloBlackBerryScreen extends MainScreen implements SystemListener2 {
    private BasicEditField basicEditField;
    private Player HEV;    
    private String wav;
    private InputStream stream;
    private int volume; //going to set volume from GUI using a drop down list, working on it currently

public HelloBlackBerryScreen() 
{
    super( MainScreen.VERTICAL_SCROLL | MainScreen.VERTICAL_SCROLLBAR );
    setTitle( "HelloBlackBerry" );
    add(new RichTextField("Battery", RichTextField.TEXT_ALIGN_HCENTER));

    Application.getApplication().addSystemListener(this);
    
    wav = "voice_on.wav";
    stream = (InputStream)this.getClass().getResourceAsStream("/" + wav);               
    try {
        HEV = Manager.createPlayer(stream, "audio/wav");
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (MediaException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public void batteryGood() {
    // TODO Auto-generated method stub
    
}

public void batteryLow() {
    // TODO Auto-generated method stub
    
}

public void batteryStatusChange(int status) 
{
    // TODO Auto-generated method stub
    if ((status & DeviceInfo.BSTAT_LEVEL_CHANGED) != 0)
    {
        if(DeviceInfo.getBatteryLevel() == 100)
        {
            try 
            {
                setWav("power_level_is_100_percent.wav"); 
                HEV.start();
                stream.close();
            } 
            catch (MediaException e) 
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } 
            catch (IOException e) 
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }               

        }               

    }
}   

public void powerOff() {
    // TODO Auto-generated method stub
    
}

public void powerUp() {
    // TODO Auto-generated method stub
    
}

public void backlightStateChange(boolean on) {
    // TODO Auto-generated method stub
    
}

public void cradleMismatch(boolean mismatch) {
    // TODO Auto-generated method stub
    
}

public void fastReset() {
    // TODO Auto-generated method stub
    
}

public void powerOffRequested(int reason) {
    // TODO Auto-generated method stub
    
}

public void usbConnectionStateChange(int state) 
{
    // TODO Auto-generated method stub
    if (state == USB_STATE_CABLE_CONNECTED) 
    {           
        try 
        {
            setWav("suitchargeok1.wav"); 
            HEV.start();
            stream.close();
        } 
        catch (MediaException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (IOException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }       
        
        } 
        else if (state == USB_STATE_CABLE_DISCONNECTED) 
        {
            try 
            {
                stream.close();
                setWav("battery_pickup.wav"); 
                HEV.start();
                stream.close();
            } catch (MediaException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();                    
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
}

public String getWav() {
    return wav;
}

public void setWav(String wav) {
    this.wav = wav;
    stream = (InputStream)this.getClass().getResourceAsStream("/" + this.wav);
    try {
        HEV = Manager.createPlayer(stream, "audio/wav");
        HEV.realize();
        VolumeControl volume = (VolumeControl) HEV.getControl("VolumeControl");
        volume.setLevel(25);
        HEV.prefetch();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (MediaException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public boolean onClose()
{
    UiApplication.getUiApplication().requestBackground();
    return true;
}

}

Answer 1

I’d need a little more clarification on how you want the app to work (see my comment below your question), but I’m pretty sure you’re going to need to implement a SystemListener (actually, a SystemListener2, which is a kind of SystemListener) to listen for USB state changes.

Something like this to detect the connection:

void usbConnectionStateChange(int state) {
   if (state == USB_STATE_CABLE_CONNECTED) {
      // start playing your sound
   } else if (state == USB_STATE_CABLE_DISCONNECTED) {
      // stop playing your sound, and exit, or just stay in the background
   }
}

Here is a link on how to add/register a System Listener on device startup

See this BlackBerry forums link on detecting USB connection

And the API docs on SystemListener2, too

Update: as I believe the poster already figured out (based on the code update in the question), the public void batteryStatusChange(int status) method is probably the more direct callback to use here. Everything else is the same, though, as that’s just another callback in SystemListener.