S60 3rd Edition MIDP 2.0 BackLight

[sanket2612]

Hi,
I need to control the backlight of a S60 3rd edition MIDP 2.0 device. However, if I try using the Nokia UI, the application does not build since Nokia UI was discontinued after MIDP1.0. The result is not satisfactory on using the standard Java function flashBackLight() of the Display class. The device behaves in a very unpredictable manner. It behaves as expected in certain cases, but the screen turns dark in some cases, if there is a key pressed event and the back light turns off for the rest of the application flow. Is there any other device specific way to control the backlight of Nokia devices?
Awaiting a reply.

[hartti]

The Nokia UI is still in the devices although it is deprecated. So there is likely some issue with your build environment.
But event with the Nokia UI API the control of the backlight is not working on all S60 devices. see also this KI
http://wiki.forum.nokia.com/index.ph...on_S60_devices

Hartti

[sanket2612]

Hi Harti,
Thanks a lot for your interest. I was indeed using the wrong build environment. After using the Nokia SDK with NetBeans, the build issue is resolved, however the DeviceControl.flashBacklight() still works in an unpredictable manner in the S60 devices.
As for the DeviceControl.setLight(), does this function override the phone. I have a display timeout on the phone of 15 seconds. The setLight() is getting called every 25 seconds. Still the back light is on for the whole duration of the application flow.
Thanks in advance.

[ehudshapira]

I think setting setLights() every n seconds is needed only for *some* phones. And maybe these phones are the exception rather than the norm. Calling it once was enough, in my testing, for N95, 6230 and some emulators.

[sanket2612]

Hi,
Well in my case, I want the light to go off after the timeout and light up again once the condition is met, to acquire the user's attention. However, after setting the back light through DeviceControl.setlight() the back light is not turned off even after the phone's display timeout. So, does the setLight() function override the phone ?
Thanks

[ehudshapira]

So you want the normal light timeout to stay in effect?

flashBackLight() seems like the main function for alerting the user without disrupting the normal light timeout, but you say it doesn't work right. Besides turning the light off yourself, I don't know how, if at all, you can restore the phone's own light control.

[ddbhasin]

How would you turn the light off yourself? What function would be used to do that?

thanks.

[sanket2612]

Hi,
There isnt any function as such for switching off the backlight.
But the setLight(a,b) takes in two parameters, a- (which light?)....currently 0 for backlight and b-brightness - range 0 to 100. So, setLight(0,0) should ideally turn off the light.

[ehudshapira]

0 turns off light, at least on the phones I tried.

[edurodel]

Hi all,

I have a similar problem here with S40/S60 platforms. Once I discovered that flashBacklight() method in a TimerTask() was not working as it was supposed to on these platforms (flickering and dimming problems), I tried the DeviceControl.setLight(0, 100). Well, I can build the jar with no problems, but when running it on a S40/S60 emulator (or device, N95 for example), I get this exception:

java.lang.NoClassDefFoundError: com.nokia.mid.impl.isa.ui.DeviceControl

I'm importing com.nokia.mid.ui.DeviceControl, not com.nokia.mid.impl.isa.ui.DeviceControl. Does anybody have any clue about what I'm doing wrong?

Thanks in advance.

[Adriana_P]

Hi All,

I need to disable the screen saver, and as far as I find out until now in Wiki and here, I should use Nokia's API setLights().

I have a "collateral" problem: could anyone please tell me how to import the DeviceControl?

more exactly where shoul I put this line, and what else do I need?:

import com.nokia.mid.ui.DeviceControl;

The sample code that I find and I need to use looks like:

 
while( true )
{
    DeviceControl.setLights( 0, 100 );
    Thread.sleep( 2000 );  // 2 seconds
}

Note: I am using C++.

Many thanks,
Adriana.

[bogdan.galiceanu]

more exactly where shoul I put this line, and what else do I need?:

import com.nokia.mid.ui.DeviceControl;

You put the import statement at the beginning of the midlet. Right at the top of the code.

Note: I am using C++.

What do you mean?

[Adriana_P]

Please forget my question about where to put that statement.

My application in written in Symbian C++.

The code above is in Java, and I need to find something similar in C++, so a way to disable the screen saver (or reset the timer, because as far as find out lately, disabling it is not possible.

Adriana.

[bogdan.galiceanu]

I'm not sure I understand your exact requirement, but would this help?
http://wiki.forum.nokia.com/index.ph...e_Backlight_on

[Adriana_P]

Yes, thank you.

This is a way to avoid the screen saver. The problem is that the BackLight stays ON, so batery goes low quick, so I have another problem: how to turn off the back light And this seems to not be so easy.