Develop Reference

camera2 api: after manual control white balance, it takes no effect when set back to 'auto' mode

First, I manually set the white balance using below code. It takes effect.
RggbChannelVector rggbChannelVector = ColorTemperatureConverter.convertTemperatureToRggb((int)white_balance_temperature);
previewRequestBuilder.set(CaptureRequest.COLOR_CORRECTION_MODE, CameraMetadata.COLOR_CORRECTION_MODE_TRANSFORM_MATRIX);
previewRequestBuilder.set(CaptureRequest.COLOR_CORRECTION_GAINS, rggbChannelVector);
Second, when I set back to CONTROL_AWB_MODE_AUTO(or CONTROL_AWB_MODE_DAYLIGHT) mode, it's no effect
previewRequestBuilder.set(CaptureRequest.CONTROL_AWB_MODE, CameraMetadata.CONTROL_AWB_MODE_AUTO);
on the other hand, if I haven't manual control the white balance, it takes effect when I set to CONTROL_AWB_MODE_AUTO or CONTROL_AWB_MODE_DAYLIGHT.
anyone knowns the reason? thanks very much.

Prevent screen from locking but allow dimming

I'm trying to get my Android app to keep the screen unlocked as long as the app is running. I easily solved this problem with setting this flag - WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON - in each activity.
But now I'd also like to allow the screen to dim and stay dimmed until a touch event is registered. I tried to mess with window object's screenBrightness and dimAmount but none of these worked (no changes in the brightness were made). Any ideas if I can implement this feature?
As a last resort I'd think a black dialog with alpha .5 covering the whole screen would work, but I don't know if this solution will have the same effect as an actual dim, battery-saving wise

Refreshing screen brightness instantaneously

I'm trying to set System Screen Brightness instantaneously. I'm using a service to do that. Here it the code that I'm using.
Settings.System.putInt(cResolver,
Settings.System.SCREEN_BRIGHTNESS, 255);
This code works fine. But it is not instantaneous. The screen brightness value changes but the screen still looks dull. I can confirm this by reading back the screen brightness value and it is 255. If I lock the screen and come back, the screen is fully bright. How can I achieve this that the moment I set the system brightness to the maximum, I see fully bright screen?
BTW, I want to do this using a service and not an activity!

I would take a look at this link, specifically the first answer. It's a bit hackish though.
Changing screen brightness programmatically (as with the power widget)
Essentially you need to force the screen to refresh through starting a dummy activity and then finish() said dummy activity. I would have commented but I don't have enough points.

Make screen go black

Is it possible in Android to make the screen go black? You can set the brightness to a low level but you cannot dim it until it goes black. Of course I could create an activity with just a black screen but would prefer an API that simply turns the screen off but not power down the device.

Set brightness below the system limit using alpha and save value

I've been trying to set the brightness under the limit of Android settings. There are two similar apps in Google Play doing this:
Shades
Screen Filter
The second one, even allows to use the phone with a black screen, just what I need in my app.
There are a lot of other questions about brightness but not to set it under this system limit, and I've found one question asking almost the same but not helping me:
Brightness Screen Filter
So after a lot of search I've got following code:
int brightness=0; //0 to 255, so I set it to a low level (not enough for me)
ContentResolver cResolver = getContentResolver();
//set the system brightness value, and if active, disable auto mode.
System.putInt(cResolver, System.SCREEN_BRIGHTNESS, brightness);
System.putInt(cResolver, System.SCREEN_BRIGHTNESS_MODE, System.SCREEN_BRIGHTNESS_MODE_MANUAL);
//previous lines don't set the brightness to the current screen so we set it like this:
LayoutParams layoutpars = getWindow().getAttributes();
layoutpars.screenBrightness = brightness / (float)255;
//Now we have brightness to the minimum allowed by Android but
//to achieve what these apps do, I have to reduce alpha of the window to the min
//then the screen is black like I want, and totally usable!
layoutpars.alpha=0.05f;
window.setAttributes(layoutpars);
Here the alpha is the key, this is doing what I want, but only for current window/screen, and I need to save to the system this alpha as default, like I'm doing with the brightness and the Manual mode for applying everywhere.
Do you know how I should do this? I'm unable to find a value "System.SCREEN_ALPHA" to set it with System.putInt or another way to do this.
In the other question I linked before, pheelicks replied with a suggestion of using a transparent non-touchable over screen, but this is not working for me, and the result does not give the feeling of a turned off screen like previous apps.
Thanks.

I decided to implemented this feature just inside my app with alpha. So I couldn't solve the initial question at all....
Anyways, in the end seems that the solution to this question is the one Pheelicks replied here: https://stackoverflow.com/a/4287597/1667990
-This is launching an activity to be always on top,
-with alpha to 0.0f so it be transparent,
-that redirects the touch to the activity behind:
//Let touches go through to apps/activities underneath.
Window window = activity.getWindow();
window.addFlags(FLAG_NOT_TOUCHABLE);
-And most important thing not explained in the previous link, is to set the dim behind our window to 1 (like the dim in a messagebox, but setting to the max to be black behind :D )
window.setDimAmount ((float)1.0) ;
window.setFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND,
WindowManager.LayoutParams.FLAG_DIM_BEHIND);
I haven't tried that and decided not to do it in my app as it could bring unexpected behavior in my circumstances, but I think it should definitely work, if anyone try please add your feedback!