I want to change the system brightness programmatically. For that purpose I am using this code:
WindowManager.LayoutParams lp = window.getAttributes();
lp.screenBrightness = (255);
window.setAttributes(lp);
because I heard that max value is 255.
but it does nothing. Please suggest any thing that can change the brightness. Thanks
You can use following :
//Variable to store brightness value
private int brightness;
//Content resolver used as a handle to the system's settings
private ContentResolver cResolver;
//Window object, that will store a reference to the current window
private Window window;
In your onCreate write:
//Get the content resolver
cResolver = getContentResolver();
//Get the current window
window = getWindow();
try
{
// To handle the auto
Settings.System.putInt(cResolver,
Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
//Get the current system brightness
brightness = Settings.System.getInt(cResolver, Settings.System.SCREEN_BRIGHTNESS);
}
catch (SettingNotFoundException e)
{
//Throw an error case it couldn't be retrieved
Log.e("Error", "Cannot access system brightness");
e.printStackTrace();
}
Write the code to monitor the change in brightness.
then you can set the updated brightness as follows:
//Set the system brightness using the brightness variable value
Settings.System.putInt(cResolver, Settings.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);
Permission in manifest:
<uses-permission android:name="android.permission.WRITE_SETTINGS"/>
For API >= 23, you need to request the permission through Settings Activity, described here: Can't get WRITE_SETTINGS permission
I had the same problem.
Two solutions:
here, brightness =(int) 0 to 100 range as i am using progressbar
1 SOLUTION
float brightness = brightness / (float)255;
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = brightness;
getWindow().setAttributes(lp);
2 SOLUTION
I just used dummy activity to call when my progress bar stop seeking.
Intent intent = new Intent(getBaseContext(), DummyBrightnessActivity.class);
Log.d("brightend", String.valueOf(brightness / (float)255));
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); //this is important
//in the next line 'brightness' should be a float number between 0.0 and 1.0
intent.putExtra("brightness value", brightness / (float)255);
getApplication().startActivity(intent);
Now coming to the DummyBrightnessActivity.class
public class DummyBrightnessActivity extends Activity{
private static final int DELAYED_MESSAGE = 1;
private Handler handler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
handler = new Handler() {
@Override
public void handleMessage(Message msg) {
if(msg.what == DELAYED_MESSAGE) {
DummyBrightnessActivity.this.finish();
}
super.handleMessage(msg);
}
};
Intent brightnessIntent = this.getIntent();
float brightness = brightnessIntent.getFloatExtra("brightness value", 0);
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = brightness;
getWindow().setAttributes(lp);
Message message = handler.obtainMessage(DELAYED_MESSAGE);
//this next line is very important, you need to finish your activity with slight delay
handler.sendMessageDelayed(message,200);
}
}
don't forget to register DummyBrightnessActivity to manifest.
hope it helps!!
I tried several solutions that others posted and none of them worked exactly right. The answer from geet is basically correct but has some syntactic errors. I created and used the following function in my application and it worked great. Note this specifically changes the system brightness as asked in the original question.
public void setBrightness(int brightness){
//constrain the value of brightness
if(brightness < 0)
brightness = 0;
else if(brightness > 255)
brightness = 255;
ContentResolver cResolver = this.getApplicationContext().getContentResolver();
Settings.System.putInt(cResolver, Settings.System.SCREEN_BRIGHTNESS, brightness);
}
WindowManager.LayoutParams layout = getWindow().getAttributes();
layout.screenBrightness = 1F;
getWindow().setAttributes(layout);
this worked for me till kitkat 4.4 but not in android L
private void stopBrightness() {
Settings.System.putInt(this.getContentResolver(),
Settings.System.SCREEN_BRIGHTNESS, 0);
}
This is the complete code on how to change system brightness
private SeekBar brightbar;
//Variable to store brightness value
private int brightness;
//Content resolver used as a handle to the system's settings
private ContentResolver Conresolver;
//Window object, that will store a reference to the current window
private Window window;
/** Called when the activity is first created. */
@Override
public void onCreate (Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Instantiate seekbar object
brightbar = (SeekBar) findViewById(R.id.ChangeBright);
//Get the content resolver
Conresolver = getContentResolver();
//Get the current window
window = getWindow();
brightbar.setMax(255);
brightbar.setKeyProgressIncrement(1);
try {
brightness = System.getInt(Conresolver, System.SCREEN_BRIGHTNESS);
} catch (SettingNotFoundException e) {
Log.e("Error", "Cannot access system brightness");
e.printStackTrace();
}
brightbar.setProgress(brightness);
brightbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
public void onStopTrackingTouch(SeekBar seekBar) {
System.putInt(Conresolver, System.SCREEN_BRIGHTNESS, brightness);
LayoutParams layoutpars = window.getAttributes();
layoutpars.screenBrightness = brightness / (float) 255;
window.setAttributes(layoutpars);
}
public void onStartTrackingTouch(SeekBar seekBar) {
}
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (progress <= 20) {
brightness = 20;
} else {
brightness = progress;
}
}
});
}
Or you may check this tutorial for complete code
happy coding:)
<uses-permission android:name="android.permission.WRITE_SETTINGS"
tools:ignore="ProtectedPermissions" />
android.provider.Settings.System.putInt(getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS,
progress);
private SeekBar Brighness = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_lcd_screen_setting);
initUI();
setBrightness();
}
private void setBrightness() {
Brighness.setMax(255);
float curBrightnessValue = 0;
try {
curBrightnessValue = android.provider.Settings.System.getInt(
getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS);
} catch (Settings.SettingNotFoundException e) {
e.printStackTrace();
}
int screen_brightness = (int) curBrightnessValue;
Brighness.setProgress(screen_brightness);
Brighness.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
int progress = 0;
@Override
public void onProgressChanged(SeekBar seekBar, int progresValue,
boolean fromUser) {
progress = progresValue;
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// Do something here,
// if you want to do anything at the start of
// touching the seekbar
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
android.provider.Settings.System.putInt(getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS,
progress);
}
});
}
initUI(){
Brighness = (SeekBar) findViewById(R.id.brightnessbar);
}
Add this in manifest
<uses-permission android:name="android.permission.WRITE_SETTINGS"
tools:ignore="ProtectedPermissions"/>
Please Try this , it's May help you. Worked fine for me
According to my experience
1st method.
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = 75 / 100.0f;
getWindow().setAttributes(lp);
where the brightness value very according to 1.0f.100f is maximum brightness.
The above mentioned code will increase the brightness of the current window. If we want to increase the brightness of the entire android device this code is not enough, for that we need to use
2nd method.
android.provider.Settings.System.putInt(getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS, 192);
Where 192 is the brightness value which very from 1 to 255. The main problem of using 2nd method is it will show the brightness in increased form in android device but actually it will fail to increase android device brightness.This is because it need some refreshing.
That is why I find out the solution by using both codes together.
if(arg2==1)
{
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = 75 / 100.0f;
getWindow().setAttributes(lp);
android.provider.Settings.System.putInt(getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS, 192);
}
It worked properly for me
WindowManager.LayoutParams params = getWindow().getAttributes();
params.screenBrightness = 10; // range from 0 - 255 as per docs
getWindow().setAttributes(params);
getWindow().addFlags(WindowManager.LayoutParams.FLAGS_CHANGED);
This worked for me. No need of a dummy activity. This works only for your current activity.
You need to create the variable:
private WindowManager.LayoutParams mParams;
then override this method (to save your previous params):
@Override
public void onWindowAttributesChanged(WindowManager.LayoutParams params) {
mParams = params;
super.onWindowAttributesChanged(params);
}
than where you wish to change the screen brightness (on the app) just use:
mParams.screenBrightness = 0.01f; //use a value between 0.01f for low brightness and 1f for high brightness
getWindow().setAttributes(mParams);
tested on api version 28.
来源：https://stackoverflow.com/questions/18312609/change-the-system-brightness-programmatically