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How one can programmatically change brightness on Android app display screen and mirror it at system degree

That has been generally practiced by growing the brightness of the gadget when scanning or displaying QR codes for fee. I’ve come throughout a number of apps that comply with this follow, most of them being pockets or banking apps.

Now, there are 2 methods to realize this. With and with out permission. Let’s begin with the straightforward one.

The simplest method is to easily modify the display screen brightness with out affecting the system brightness.

You’ll be able to set the screenBrightnesswindow attribute, like so

val structure: WindowManager.LayoutParams? = exercise?.window?.attributes
structure?.screenBrightness = 0.9f
exercise?.window?.attributes = structure

He screenBrightness The attribute is a floating level worth starting from 0 to 1, the place 0.0 is 0% brightness, 0.5 is 50% brightness, and 1.0 is 100% brightness.

Be aware that this doesn’t have an effect on the brightness of the whole system, just for that specific window. Nevertheless, usually, for many purposes, that is most likely all you want. Specifically, it has the benefit of not requiring elevated permissions, which might be vital to alter a worldwide system setting.

Step one can be so as to add WRITE_SETTINGS permission in android manifest

<uses-permission android:title="android.permission.WRITE_SETTINGS"
instruments:ignore="ProtectedPermissions"/>

WRITE_SETTINGS it’s a protected configuration that asks the consumer to permit writing of the system configuration.

if (Construct.VERSION.SDK_INT >= Construct.VERSION_CODES.M) 
if (!Settings.System.canWrite(this)) 
Intent intent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS);
intent.setData(Uri.parse("package deal:" + getPackageName()));
startActivity(intent);

Now once you run your app, it can ask the consumer to permit the app to change system settings from throughout the app. In case your app is signed with system certificates, your app could have this permission by default.

The subsequent step is to configure the brightness of the applying. This time we’ll simply cross the worth to the system and let the system deal with the gadget’s brightness as an alternative of setting it manually.

Settings.System.putInt(context.getContentResolver(), 
Settings.System.SCREEN_BRIGHTNESS, brightness);

brightness the worth should be within the vary of 0-255. So in case you have a slider with a variety (0-max), you possibly can normalize the worth to the vary of (0–255)

personal float normalize(float x, float inMin, float inMax, float outMin, float outMax) 
float outRange = outMax - outMin;
float inRange  = inMax - inMin;
return (x - inMin) *outRange / inRange + outMin;

Lastly, now you can change the vary of the slider worth (0–100%) to 0–255 like this

float brightness = normalize(progress, 0, 100, 0.0f, 255.0f);

This might permit your app to cross the brightness to the Android system and it’ll improve the brightness of your gadget.