Changing Screen brightness in 6.0 programmatically

Question

I am working on an android application which changes the screen brightness programmatically. I have a set brightness method which works on 5.1.1,But when i run the application on 6.0,it gives an error and closes the application. Please Help.

Following is my approach:

 public void setBrightness(View view,int brightness){

    //Just a loop for checking whether the brightness changes
     if(brightness <46)
        brightness = 255;
    else if(brightness >150)
        brightness=45;
    ContentResolver cResolver = this.getApplicationContext().getContentResolver();
    Settings.System.putInt(cResolver, Settings.System.SCREEN_BRIGHTNESS, brightness);

}

public void setDisplay(View view)
{
    ContentResolver  cResolver = getContentResolver();

    Window window = getWindow();
    int brightness=0;
    try
    {        Settings.System.putInt(cResolver,Settings.System.SCREEN_BRIGHTNESS_MODE
                                   Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
                   brightness = Settings.System.getInt(cResolver, Settings.System.SCREEN_BRIGHTNESS);
        System.out.println("Current Brightness level " + brightness);
    }
    catch (Exception e)
    {
                   Log.e("Error", "Cannot access system brightness");
        e.printStackTrace();
    }
    setBrightness(view,brightness);
}

Answer 1

Apparently you need to explicitly ask the user for permission on devices running Android 6.0+.

Try the following code: (I have modified it for you)

@TargetApi(Build.VERSION_CODES.M)
public void setBrightness(View view,int brightness){

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        if (Settings.System.canWrite(getApplicationContext()))
        {
            if (brightness < 46)
                brightness = 255;
            else if (brightness > 47)
                brightness = 0;

            ContentResolver cResolver = this.getApplicationContext().getContentResolver();
            Settings.System.putInt(cResolver, Settings.System.SCREEN_BRIGHTNESS, brightness);

        } else

        {
            Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_WRITE_SETTINGS);
            intent.setData(Uri.parse("package:" + this.getPackageName()));
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
        }
}

Note that you need the WRITE_SETTINGS permission in your manifest, also.