Develop Reference

Brightness goes normal after changing activity

I was trying to switch between 'full brightness' and 'phones normal brightness' by using a switch button in my main activity.
I successfully handled the switching of brightness by using this code:
switchButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton, boolean bChecked) {
if (bChecked) {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = 1.0f;
getWindow().setAttributes(params);
} else {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_NONE;
getWindow().setAttributes(params);
}
}
});
if (switchButton.isChecked()) {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = 1.0f;
getWindow().setAttributes(params);
} else {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_NONE;
getWindow().setAttributes(params);
}
The problem is,
after switching to 'full Brightness', when I change the activity, the brightness goes normal.
Now, How can I keep track of the 'brightness setting' from 'main activity' and apply it to the other activities of the app?
N.B. I don't want to change system brightness. Brightness will only change while using the app.
Thanks In Advance.

ok.
Finally solved my problem.
I have created a class having the logic of brightness controlling using SharedPreferences to Handle the state.
code:
if (br.getString("set", "").equals("1")) {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = 1.0f;
getWindow().setAttributes(params);
} else {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_NONE;
getWindow().setAttributes(params);
}
Then extend the class with the activities and initialize SharedPreferences in onCreate method.
br = getSharedPreferences("br", Activity.MODE_PRIVATE);
Thank you #0X0nosugar for the idea.

You need to hold a SCREEN_BRIGHT_WAKE_LOCK if you want it to have an effect beyond your activity. The method you are using above applies to the foreground window, and when you activity goes away that no longer applies.
Note Android generally frowns on use of wake locks because it's easy to screw up and not release them, wasting the devices battery. They recommend the window param version for the vary reason that it automatically releases when the user leaves the activity.

How do you set brightness of screen in Android?

I want a dialog that adjusts brightness of the screen using SeekBar.
How to display custom dialog with SeekBar that adjusts brightness of screen?

You can use this API. This will change screen brightness of your window and not of the whole system.
// Make the screen full bright for this activity.
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = 1.0f;
getWindow().setAttributes(lp);

This code snippet should help you
pdlg = ProgressDialog.show(getParent(), "Loading...", "");
WindowManager.LayoutParams lp = pdlg.getWindow().getAttributes();
p.dimAmount=0.0f; //Dim Amount
pdlg.getWindow().setAttributes(lp); //Applying properties to progress dialog
pdlg.dismiss(); //Dismiss the dialog

Hey you can set the system brightness like this:
//Set the system brightness using the brightness variable value
System.putInt(cResolver, System.SCREEN_BRIGHTNESS, brightness);
//Get the current window attributes
LayoutParams layoutpars = window.getAttributes();
//Set the brightness of this window
layoutpars.screenBrightness = brightness / (float)255;
//Apply attribute changes to this window
window.setAttributes(layoutpars);
Or you may refer on this complete tutorial

Changing screen brightness programmatically (as with the power widget)

I was searching how to change the brightness of the screen programmatically and I found this it is very good solution and it works nice, but it works only while my app is active. After my application is shutdown then the brightness is returned back the the same value as before I start my app.
I want to be able to change the brightness just like when I press on the brightness button from my power widget. In the power widget that comes from android there are 3 states. One very bright one very dark and one in between. Is it possible to change the brightness just like when someone press on this widget ?
Edit1:
I created this and I added permision to my manifest but when the app is started I do not see any changes to the brightness, I tried with 10 with 100 and now with 200 but no changes
any suggestions ?
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
android.provider.Settings.System.putInt(this.getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS, 200);
}

This is the complete code I found to be working:
Settings.System.putInt(this.getContentResolver(),
Settings.System.SCREEN_BRIGHTNESS, 20);
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness =0.2f;// 100 / 100.0f;
getWindow().setAttributes(lp);
startActivity(new Intent(this,RefreshScreen.class));
The code from my question does not work because the screen doesn't get refreshed. So one hack on refreshing the screen is starting dummy activity and than in on create of that dummy activity to call finish() so the changes of the brightness take effect.

Use Tor-Morten's solution in that link, but also set the system brightness setting like so:
android.provider.Settings.System.putInt(getContext().getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS, bright);
Where bright is an integer ranging from 1 to 255.

I have solved this problem today.
As the first you have to put a permission into your AndroidManifest.xml file:
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
Where is the exact place to put it in the file?
<manifest>
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<application>
<activity />
</application>
</manifest>
This permission says, that you are allowed to change settings that affect other applications too.
Now you can set brightness automatic mode on and off
Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC); //this will set the automatic mode on
Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL); //this will set the manual mode (set the automatic mode off)
Is the automatic mode turned on or off right now? You can get the information
int mode = -1;
try {
mode = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE); //this will return integer (0 or 1)
} catch (Exception e) {}
So, if you want to change brightness manually, you are supposed to set the manual mode first and after that you can change the brightness.
note: SCREEN_BRIGHTNESS_MODE_AUTOMATIC is 1
note: SCREEN_BRIGHTNESS_MODE_MANUAL is 0
You should use this
if (mode == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC) {
//Automatic mode
} else {
//Manual mode
}
instead of this
if (mode == 1) {
//Automatic mode
} else {
//Manual mode
}
Now you can change the brightness manually
Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, brightness); //brightness is an integer variable (0-255), but dont use 0
and read brightness
try {
int brightness = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS); //returns integer value 0-255
} catch (Exception e) {}
Now everything is set properly, but... you can't see the change yet.
You need one more thing to see the change!
Refresh the screen... so do this:
try {
int br = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS); //this will get the information you have just set...
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = (float) br / 255; //...and put it here
getWindow().setAttributes(lp);
} catch (Exception e) {}
Don't forget the permission...
<uses-permission android:name="android.permission.WRITE_SETTINGS" />

Passing the context of the activity while setting up the parameters would also get the job done without any need to start another activity.
The following worked for me-
WindowManager.LayoutParams lp = this.getWindow().getAttributes();
lp.screenBrightness =0.00001f;// i needed to dim the display
this.getWindow().setAttributes(lp);
i had this piece of code inside onSensorChanged() method which dimmed the display whenever it was triggered.

COMPLEX EXAMPLE:
try {
//sets manual mode and brightnes 255
Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL); //this will set the manual mode (set the automatic mode off)
Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, 255); //this will set the brightness to maximum (255)
//refreshes the screen
int br = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS);
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = (float) br / 255;
getWindow().setAttributes(lp);
} catch (Exception e) {}

Can't apply system screen brightness programmatically in Android

I'm using the following to set the system auto brightness mode and level:
android.provider.Settings.System.putInt(y.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS_MODE, 0);
android.provider.Settings.System.putInt(y.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS, y.brightness1);
I can change auto-brighess on and off, and set different levels. The settings seem to be applied properly -- I can go to into Settings --> Display --> Brightness, and whanever setting I set is actually shown correctly. However, the actual screen isn't changing its brightness. If i just tap on the slider in Display Settings, then everything gets applied.
I shoudl mention that I'm running an app withat a main activity, and these settings are getting applied in the BroadcastReceiver. I did try to create a dummy activity and tested the stuff there, but got the same results.

OK, found the answer here:
Refreshing the display from a widget?
Basically, have to make a transparent activity that processes the brightness change. What's not mentioned in the post is that you have to do:
Settings.System.putInt(y.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS_MODE, 0);
Settings.System.putInt(y.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS, brightnessLevel);
then do
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = brightness;
getWindow().setAttributes(lp);
And if you call finish() right after applying the changes, brightness will never actually change because the layout has to be created before the brightness settings is applied. So I ended up creating a thread that had a 300ms delay, then called finish().

I'm doing something similar with screen brightness in one of my apps, and I'm doing it through the WindowManager and it works. I'm using the following code to get the current screen brightness (and save it for later) and set it to full:
WindowManager.LayoutParams lp = getWindow().getAttributes();
previousScreenBrightness = lp.screenBrightness;
float brightness = 1;
lp.screenBrightness = brightness;
getWindow().setAttributes(lp);

Use the answer given by "user496854" above
If you are taking max screenBrightness =255 then while doing
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = brightness; getWindow().setAttributes(lp);
divide screenBrightness by 255 like
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = brightness/(float)255;
getWindow().setAttributes(lp);

I created a static method in my Application class which I invoke from all my Activity.onResume() methods.
MyApplication extends Application {
...
public static void setBrightness(final Activity context) {
// get the content resolver
final ContentResolver cResolver = context.getContentResolver();
// get the current window
final Window window = context.getWindow();
try {
// get the current system brightness
int brightnessLevel = System.getInt(cResolver,System.SCREEN_BRIGHTNESS);
// get the current window attributes
LayoutParams layoutpars = window.getAttributes();
// set the brightness of this window
layoutpars.screenBrightness = brightnessLevel / (float) 255;
// apply attribute changes to this window
window.setAttributes(layoutpars);
} catch (SettingNotFoundException e) {
// throw an error cuz System.SCREEN_BRIGHTNESS couldn't be retrieved
Log.e("Error", "Cannot access system brightness");
e.printStackTrace();
}
}
}
MyActivity extends Activity {
...
public void onResume() {
super.onResume();
Log.d(TAG, "onResume()");
MyApplication.setBrightness(this);
}
}

Brightness Screen Filter

Does anyone have an idea how to implement an Brightness Screen Filter like the one here:
http://www.appbrain.com/app/screen-filter/com.haxor
I need a starting point and I can't figure out how to do it.

Just make a transparent full screen activity that lets touches pass through. To make touches pass through use the following Window flags before setting the contentView:
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
Window window = getWindow();
// Let touches go through to apps/activities underneath.
window.addFlags(FLAG_NOT_TOUCHABLE);
// Now set up content view
setContentView(R.layout.main);
}
For your main.xml layout file just use a full screen LinearLayout with a transparent background:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/background"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#33000000">
</LinearLayout>
Then to adjust the "brightness" just change the value of the background colour from your code somewhere:
findViewById(R.id.background).setBackgroundColor(0x66000000);

Get an instance of WindowManager.
WindowManager windowManager = (WindowManager) Class.forName("android.view.WindowManagerImpl").getMethod("getDefault", new Class[0]).invoke(null, new Object[0]);
Create a full screen layout xml(layout parameters set to fill_parent)
Set your view as not clickable, not focusable, not long clickable, etc so that touch is passed through to your app and the app can detect it.
view.setFocusable(false);
view.setClickable(false);
view.setKeepScreenOn(false);
view.setLongClickable(false);
view.setFocusableInTouchMode(false);
Create a layout parameter of type android.view.WindowManager.LayoutParams.
LayoutParams layoutParams = new LayoutParams();
Set layout parameter like height, width etc
layoutParams.height = LayoutParams.FILL_PARENT;
layoutParams.width = LayoutParams.FILL_PARENT;
layoutParams.flags = 280; // You can try LayoutParams.FLAG_FULLSCREEN too
layoutParams.format = PixelFormat.TRANSLUCENT; // You can try different formats
layoutParams.windowAnimations = android.R.style.Animation_Toast; // You can use only animations that the system to can access
layoutParams.type = LayoutParams.TYPE_SYSTEM_OVERLAY;
layoutParams.gravity = Gravity.BOTTOM;
layoutParams.x = 0;
layoutParams.y = 0;
layoutParams.verticalWeight = 1.0F;
layoutParams.horizontalWeight = 1.0F;
layoutParams.verticalMargin = 0.0F;
layoutParams.horizontalMargin = 0.0F;
Key step: You can set what percentage of brightness you need.
layoutParams.setBackgroundDrawable(getBackgroundDrawable(i));
private Drawable getBackgroundDrawable(int i) {
int j = 255 - (int) Math.round(255D * Math.exp(4D * ((double) i / 100D) - 4D));
return new ColorDrawable(Color.argb(j, 0, 0, 0));}
Finally add view to windowManager that you created earlier.
windowManager.addView(view, layoutParams);
Note: You need SYSTEM_ALERT_WINDOW permission to lay an overlay on the screen.
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
Have tested this and it works. Let me know if you get stuck.

Of course you can't use this is production code, but if you are playing around .. try this Undocumented hack
It uses :
private void setBrightness(int brightness) {
try {
IHardwareService hardware = IHardwareService.Stub.asInterface(
ServiceManager.getService("hardware"));
if (hardware != null) {
hardware.setScreenBacklight(brightness);
}
} catch (RemoteException doe) {
}
}
Remember that it uses this permission :
<uses-permission android:name="android.permission.HARDWARE_TEST"/>

You ca try this also:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.max_bright);
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = 100 / 100.0f;
getWindow().setAttributes(lp);
}