The goal of my app is to keep the screen on across the whole Android system. Previously, I've used FULL_WAKE_LOCK for this and it allowed me to block dimming of the screen across the system. However, since the API Level 17, it got deprecated:
This constant was deprecated in API level 17. Most applications should
use FLAG_KEEP_SCREEN_ON instead of this type of wake lock, as it will
be correctly managed by the platform as the user moves between
applications and doesn't require a special permission.
Official documentation recommends using FLAG_KEEP_SCREEN_ON, however it is possible to use it only for particular Activity.
I would still FULL_WAKE_LOCK, however I've found that it doesn't work now on some of the devices, like MediaPad Huawei x2, Redmi Note 3, etc. The way I'm currently using the PowerManager can be found on GitHub. Is there any better way to do accomplish this task after API level 17?
Starting with API 23 and its new Doze mode Wake Locks are ignored and they do not prevent the system from entering sleep.
You should experiment with maintaining a foreground service in parallel with the wake lock, theoretically that should prevent the device from entering sleep.
NOTE: the foreground Service has to call startForeground and show a non dismissable Notification
Related
As the title says, I am looking for a way to monitor the level of the device battery even while the app is not running.
context.registerReceiver() worked out well, but sadly only with the app running.
Is there any way I did not think of?
This is became restricted starting from Android 8+. Have a look at the documentation ACTION_BATTERY_CHANGED
You might try WorkManager to periodically check for battery status
Background
Smart Lock feature allows to fully unlock the device under certain conditions, such as GPS location, connected Bluetooth, etc...
The problem
I'd like to make an app that does that, with other special conditions.
Given user's approval, is it possible to completely unlock the lock screen, even if it has a password, so that the user will continue as if he unlocked the device by himself?
What I've found
I know it's probably possible using accessibility service, to mimic user actions of entering the code or drawing the pattern.
There is probably a way to temporarily disable the lock screen, by using keyguard API (written here for example), but as I've read, those are deprecated and might not work on some devices and Android versions. I guess it also requires to have a foreground service for it to continue staying on this state.
The questions
Is there a better way? Is there a way to unlock the device, just like Smart Lock feature?
If so, how?
Is it true the Keyguard API is not recommended? What is there to worry about when using it? Or maybe it's completely safe to use, and can be used to fully unlock?
I have a foreground notification service that continuously monitors user's actions, using ActivityRecognition, and writes them to AWS anytime user's state changes. It works good for some time. However I noticed when user is idle for longer time, such as user is sleeping overnight, then the app (activity and service) silently dies. I assume this is because of doze mode (because I whitelisted the same app on a different phone and it is working fine for over 2 days now)
How to WhiteList app in Doze mode Android 6.0 gives good overview on how to disable doze mode with user intervention. But #commonsware blog below suggests about Google 'possibly' banning the apps that show the corresponding popup box
https://commonsware.com/blog/2015/11/11/google-anti-trust-issues.html
Note: Google Play policies prohibit apps from requesting direct exemption from Power Management features in Android 6.0+ (Doze and App Standby) unless the core function of the app is adversely affected.
Can someone help me in understanding what features can possibly comprise "core functions", so Google would not ban my app. We know doze mode doesn't affect some apps like WhatsApp
EDIT
I see this on Samsung phones with 6.0.1
Android does not kill services in the background with Doze. Per the ActivityRecognitionApi documentation:
To conserve battery, activity reporting may stop when the device is 'STILL' for an extended period of time. It will resume once the device moves again. This only happens on devices that support the Sensor.TYPE_SIGNIFICANT_MOTION hardware.
Therefore it is entirely expected to have a significant period of time where you won't get any activity recognition callbacks. In those cases, you can assume that the last received activity (STILL) is still applicable.
I have an android app which records voice using a service - and a thread inside the service(obviously the app can record while in background..)
The app will be affected by the new Doze app state?
https://developer.android.com/training/monitoring-device-state/doze-standby.html#whitelisting-cases
I don't have a phone with 6.0 yet and the simulator cannot record voice in general...
If your service is running in the foreground (with an associated notification) when the device enters Doze mode, it should not be affected according to a comment by Dianne Hackborn to this post. See a documented experience that seems to prove this behavior here.
On the other hand, tests show, that access to certain sensors like GPS are restricted in Doze mode, so this might also apply to the microphone.
Since Doze mode is poorly documented up to now, unfortunately at this point you probably do not get around running your own tests on a physical device.
Yes, every app can be "killed" by Doze. If your service runs in foreground you can avoid App Standby however. Remember that asking to the user to put the app in the whitelist it's prohibited from Google Terms of services, so you can't do it. If you want to do something like that you need to add a permission to your manifest and with cross fingers hope in the Google review of your app.
I have a Service that keeps the display on at a dim level at certain times, and it uses a 'dim' WakeLock to accomplish this. It works well... except that the screen never locks. That is, while the dim WL is held, the lock screen never appears requiring the user to swipe and authenticate.
Note that I'm developing on a platform that may have vendor changes to the low-level Android Java framework code, so this might not be standard Android behavior. But also, I have access to the framework code and can change it, if necessary. I just can't figure out where this policy is enforced in the code.
When the device is on external power, we want to keep the screen contents visible - but we still want it to lock.
The only way I can think of to do that is for you to maintain your own timer for when to trigger the lock, then to use DevicePolicyManager and lockNow() to lock the device at that point. This requires extra permissions and extra setup work (enabling your app as a device manager).