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Phone Display Brightness
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Change the global brightness from a service
Still is not any way to change the brightness globally from a service?
Still is not any way to change the brightness globally from a service?
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There are lot of widgets on the Market which can adjust the brightness (switch between auto, or 25%-100%). Or there is an app (Brightness Battery Widget) which can adjust the brightness depending the battery level, and lot of "battery saver" apps can do this.
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You can set some System settings without problem. Some time ago I wrote a testing library for that and it works without problem to set the device brightness.
Setting screen brightness from a service is somewhat tricky because just changing the device settings does not really change the brightness. You still have to open a (invisible) dummy Activity and use Phone.SetScreenBrightness().
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You can do it with Reflection. Use this Sub to set a Android Setting:
Your App needs the WRITE_SETTINGS permission to make changes, so add this in the Manifest Editor:
Now you can change the brightness:
You always have to call both:
WriteSetting to change the system setting (this does not affect current brightness)
Phone.SetScreenBrightness() to change current brightness.
Be aware that very small values switches the display completely off so the example only sets brightness, if Value is bigger than 15 (Value has a range from 0 to 255)
If you want to do this from a service like from a widget its much more tricky since you can't call Phone.SetScreenBrightness() from a service module. Then you have to startup an invisible activity (define transparent theme for it in manifest), call Phone.SetScreenBrightness() from this activity and exit the activity immediately.
For a list of settings you can change look here.
PS: Hey, I'm beginning to understand reflection. :sign0104:
B4X:
Sub WriteSetting(Setting As String, Value As Int)
Dim r1 As Reflector
Dim args(3) As Object
Dim types(3) As String
r1.Target = r1.GetContext
args(0) = r1.RunMethod("getContentResolver")
types(0) = "android.content.ContentResolver"
args(1) = Setting
types(1) = "java.lang.String"
args(2) = Value
types(2) = "java.lang.int"
r1.RunStaticMethod("android.provider.Settings$System", "putInt", args, types)
End SubYour App needs the WRITE_SETTINGS permission to make changes, so add this in the Manifest Editor:
B4X:
AddPermission("android.permission.WRITE_SETTINGS")Now you can change the brightness:
B4X:
Dim p As Phone
If Value > 15 Then
WriteSetting("screen_brightness", Value)
p.SetScreenBrightness(Value/255)
End IfYou always have to call both:
WriteSetting to change the system setting (this does not affect current brightness)
Phone.SetScreenBrightness() to change current brightness.
Be aware that very small values switches the display completely off so the example only sets brightness, if Value is bigger than 15 (Value has a range from 0 to 255)
If you want to do this from a service like from a widget its much more tricky since you can't call Phone.SetScreenBrightness() from a service module. Then you have to startup an invisible activity (define transparent theme for it in manifest), call Phone.SetScreenBrightness() from this activity and exit the activity immediately.
For a list of settings you can change look here.
PS: Hey, I'm beginning to understand reflection. :sign0104:
Last edited:
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I looked at the Lib tab and didn't see Reflection in there so I assume I don't have to manually add it (it's built-in)?
I don't know how to add the Sub function into my current Activity for the WriteSetting? Do I need to create a new Code Module and add it there or can I add it to my existing Activity module?
I don't know how to add the Sub function into my current Activity for the WriteSetting? Do I need to create a new Code Module and add it there or can I add it to my existing Activity module?
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Dear friends
please for advice...
How to solve situation if I want use this code (from this thread) in service:
I am using it in main aktivity. Everything is ok, but if I use it in service, the APP crashed.
I need use it in service. It is possible?
Please can you show me right direction, how to solve it?
Thank you very much
p4ppc
please for advice...
How to solve situation if I want use this code (from this thread) in service:
B4X:
Dim p AsPhone
If Value > 15Then
WriteSetting("screen_brightness", Value)
p.SetScreenBrightness(Value/255)
EndIf
Sub WriteSetting(Setting As String, Value As Int)
Dim r1 As Reflector
Dim args(3) As Object
Dim types(3) As String
r1.Target = r1.GetContext
args(0) = r1.RunMethod("getContentResolver")
types(0) = "android.content.ContentResolver"
args(1) = Setting
types(1) = "java.lang.String"
args(2) = Value
types(2) = "java.lang.int"
r1.RunStaticMethod("android.provider.Settings$System", "putInt", args, types)
End SubI need use it in service. It is possible?
Please can you show me right direction, how to solve it?
Thank you very much
p4ppc
Last edited:
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Erel, thank you,
In service module where I am using PHONEEVENTS (this is OK)
I am waiting to STATE="OFFHOOK" (this is OK)
after that in same service I change brightness with
and the app crashed with message: The app stop working
with this error message:
Thank you very much
p4ppc
In service module where I am using PHONEEVENTS (this is OK)
I am waiting to STATE="OFFHOOK" (this is OK)
after that in same service I change brightness with
B4X:
sub contrastplus
Dim val As Int
val=20
Dim ph As Phone
WriteSettingg("screen_brightness", val)
phk.SetScreenBrightness(val/255)
End sub
Sub WriteSettingg(Setting AsString, Value AsInt)
Dim r1 AsReflector
Dim args(3) AsObject
Dim types(3) AsString
r1.Target = r1.GetContext
args(0) = r1.RunMethod("getContentResolver")
types(0) = "android.content.ContentResolver"
args(1) = Setting
types(1) = "java.lang.String"
args(2) = Value
types(2) = "java.lang.int"
r1.RunStaticMethod("android.provider.Settings$System", "putInt", args, types)
End Suband the app crashed with message: The app stop working
with this error message:
Thank you very much
p4ppc
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See the documentation for SetScreenBrightness method: https://www.b4x.com/android/forum/pages/results/?query=phone.setscreenbrightness&page=1&prefix=0
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