For this question I'm going to quote another user who got no response to their question:
I've written an Andoid app that uses the hardware Volume buttons for another purpose.
It works fine if the app is running and visible, but when I turn the
screen off or let it time out, the button clicks don't get into my
handlers.
Does anyone know if there is a way to detect these button clicks when
the screen is off?
Source: AV695's question
I'm working on an app myself that makes use of the volume buttons, but as this user also noted, the normal behavior of checking buttons with onKeyPress stops working once the screen is off. This is because the Activity gets paused on screen off.
Is there a way to keep the activity running while the screen is off, or check for the usage of the volume buttons when the screen is off? I tried using a Service for this before but it's impossible to check for the volume keys like that as noted by Commonsware.
I doubt that this is supported (without resorting to a battery-draining wakelock) at either the platform, kernel, or underlying radio firmware levels without modifications to the last to bring volume presses during sleep to the attention of the kernel.
Within the realm of reasonable system-ROM modifications, a more reasonable one might be to modify an existing open source ROM for the device to insert some custom platform level code into the handling of the power button usually used to wake up the device preparatory to unlocking it - that at least we know does get the attention of the kernel. That code could then inform the user by sound or vibration if there are unacknowledged notifications.
You could optionally wait briefly, check device orientation, or look for another key press to avoid doing this in an annoying way when the user is holding the device outside their pocket and trying to unlock it.
Or you could not use the volume key and just set a timer to wake up every 15 minutes and vibrate if there are unacknowledged notifications, avoiding the need to fumble in ones pockets.
You mention it's a custom request: if implies it's one off or low-volume, another option to consider would be that a few vendors have "bluetooth watches" out with an SDK that lets you push notifications from an android device.
If you can capture the notification when it's generated, you could push it to the user's wrist, and then let the phone go back to sleep.
You cannot intercept the key while your application is in background, but instead of listening to the KeyPress itself. You can register a ContentObserver, as described in this question.
As Chris Stratton mentioned, the only way to keep your App alive is by using battery-draining wake locks.
However, since I found myself in the same situation, I came up with another solution. Unfortunately, you'll need a rooted device as well as the Xposed framework.
With Xposed, which replaces the zygot process so you can hook yourself into any constructor and method of the system, you will be able to catch the raw KeyEvents before the system handles them.
This is done in PhoneWindowManager.interceptKeyBeforeQueueing(). By using a XC_MethodHook, you can use beforeHookedMethod() on the afore mentioned method to catch every hardware button event, even if the device is in deep sleep.
After catching events you are interested in, you can create a temporary wake lock to do your things but don't forget to release the wake lock after you finished your work.
A good example of how to accomplish this is the Xposed Torch Module.
If you, however, rely on a non rooted system, the bad news is that it's simply not possible without draining the battery...
I was also trying to implement volume button press detection in my app and I left that part to be developed later once the core part is done. I was able to detect volume key press while screen is on even when phone is locked, from a background service.
Background Video Recorder 2 (BVR2) (and possible BVR1 also, I did not try) is one of the apps that can detect volume key press even when screen is off. While trying to implement volume key detection while screen is off in my app, I installed BVR2, hoping to find how it works. To my surprise it gave my app the ablity to detect volume keys even when screen is off. My app had a ContentObserver to monitor volume changes, but was not working when screen is off. When BVR2 is active my app also could detect volume key press when screen is off. Still digging.
But BVR2 has its own trigger action, that is to record video, an action you may not want to occur just for the sake of you application detecting volume key presses.
Another app is QuickClick. This app can give your app what it lacks, the power to detect volume key presses even when screen is off, without extra unwanted actions. Just install QuickClick and do not configure any action. Create a ContentObserver to monitor for stream volume changes and you are ready. You app will now be able to detect volume key presses even when screen is off.
Please note that my app runs as a background service.
Both of the apps mentioned above are meant for other uses, but uses volume key detection to perform action. I am in no way connected to any of the apps mentioned.
If these apps, and possibly dozens others, can detect volume key press, it can be done. I request experts to find out how to do it, so that we can implement in our app without relying on another app.
If you find this answer useful, please up-vote.
I am not sure if it is as simple as this but check this android blog:
Allowing applications to play nice(r) with each other: Handling remote control buttons
It explains the usage of a broadcast receiver that receives the up/down volume controls and other music controls.
In summary you should use registerMediaButtonEventReceiver
Related
With the new Android 12 operating system, the user now has the ability to completely disable microphone and camera usage from ALL apps. This is actually a good thing, letting users easily control privacy.
If an app starts and has permission to use the microphone and the camera AND the user has disabled all access to either of these hardware, Android 12 automatically pops up an alert asking the user to re-enable the microphone or camera, or to continue with the hardware disabled for the app.
Also, on creation, the app can simply check when starting to see if the needed hardware is enabled, and can also prompt the user further or handle the condition as the app sees fit.
But what if the user disables the microphone or camera while the app is running? I can't seem to find any interfaces for something like onMicrophoneEnabled() or even a Broadcast of such an event.
It's possible to check every time onResume() is called, but I was hoping there'd be a more elegant solution.
If anyone knows of something that my app can use to capture this when the user has made changes either way, please let me know.
After carefully reading the google docs (https://developer.android.com/training/permissions/explaining-access#toggles) on their implementation of the user enable/disable of the camera and microphone I discovered something very interesting:
Apps are explicitly forbidden from knowing if the user has done any of these actions. So of course there is no way to get notified of these changes: it is by design.
If the user turns off the camera this way, the app will still get a camera feed, but it will be black. Similarly the microphone will still work, but we'll get only silence. This is a feature--a way to ensure privacy.
The operating system will remind users that they have disabled the microphone or camera and provide a chance to re-enable the hardware, which is nice. But the app is completely in the dark (hehe).
Another way to think of it: Just like putting a piece of tape over your camera or your thumb over the microphone. Only this time it's done by the operating system. This way a spy program or some other nefarious software will still think it's working and not try to bypass or give up.
This also explains why testing during onResume() or onWindowFocusChanged() didn't work either. I was getting results that didn't align with the settings (they aligned with current permissions).
So to answer my question: There is no way to be notified. That is the point.
I would like to run predefined service in my app if I do two short volume up pushes (or one long hold).
It should works also if phone has locked screen or another app is in foreground.
Thanks for any advice or example how can i do it.
The official Broadcast Receiver for volume changes only gets triggered when the state changes from volume to/from silent to/from vibrate. So perhaps, it could detect a long volume up hold under some circumstances, but I don't know. That Broadcast Receiver is not granular at all.
I've seen non-rooted apps on Google Play that detect the volume keys at a more granular level, but I believe those apps are making use of undocumented functionality (of which I do not know about).
If you're making your own rom as your username might imply, detecting those keys would be much easier to do. Is that the case? Are you making your own rom? Will the app you're making have root access?
I am aware that this question has been asked already in this site, but I could not find my answer. SO this is what i am trying ot do. My power button in my phone is not working properly. So could is there a way to override my volume up button to unlock my phone.
I am planning to implement broadcast receiver But could not find the appropriate intent-filter. Another alternative that I thought was to run a service when the screen is locked, but I am not quite sure if I can listen to key events.
So if any of the above mentioned is possible, could you hint on how to get it done or suggest another alternative?
No, It do not think so. This can not be done.
There is no broadcast for volume up or down button presently. You can implement a service that will listen for any changes in the volume but it is not recommended to run a service all the time since that consumes both battery and memory.
The only solution that I can think of is using ContentObservers for listening to the changes in the settings such as volume of streams. This answer here will provide you with the code to use ContentObserver to listen for volume up or down. https://stackoverflow.com/a/7017516/1979347
This functionality you speak of has already been done multiple times and can be found on Google Play. However, I'm not sure how they did it, or how much their solution drains the battery.
I just did a test on my G2 (Android 4.2.2), I launched a broadcast monitor, I switched to the homescreen, and I changed the volume from there.
Apparently, it can detect if the volume is turned up only when it changes from silent mode > to Vibration mode > or to Sound mode. Conversely, when pressing the down volume, I think we can detect the change when it goes from the Sound Mode > to Vibration Mode > or to Silent Mode.
This is probably not what you wanted to hear, but I just wanted to confirm what the others were saying. On a non-rooted phone, what they're saying is mostly correct. On a rooted phone however, there are custom ROMs that have solved this issue.
By the way, what brand/model is your phone? On my phone, when the headset gets connected, the phone lights up. So I suppose, one could always do it the way iPhone owners do it for their phones. You'd have to cut the extremity of a head phone jack, coat half of the pin in plastic, and super glue a button on top of it to allow you to easily twist the head.
I'm developing an app which requires the system to get the touch events even after the system goes to sleep mode or after the user locks the screen, I tried searching for a solution but it is hard to find one.
Should I want to set any permissions or is there any inbuilt methods or can I override any methods to perform this functionality.
I'm developing an app which requires the system to get the touch events even after the system goes to sleep mode or after the user locks the screen
Fortunately, this is not possible. Otherwise, the device would not be asleep, and battery life would suffer as a result.
Here is a link that shows how to prevent the phone from sleeping.
If you couple that with, say a black screen to 'pretend' the hone is sleeping but actually running your code. So your code can still intercept touch event
Then you need to install your app as a service and make it start when the device is turned on.
You will not need NDK or rooted device for that (sorry, got a short night :) )
The primary purpose of my app is to change a smart phone into a sort of smart pager (there is an associated web app, but that's not the purpose of the Android app). I use the Notification system built in to Android to handle alerting the user that they have received a page.
My problem is that the clients want:
The notification ringer to ring forever until acknowledged (easily accomplished with FLAG_INSISTENT)
An easy way to silence the ringer with 1 push of a button. It is really not always feasible due to the nature of their work to press the power button, slide to unlock, and drag down the notification bar. I need to replicate the behavior of a pager.
I need to find a way to satisfy the 2nd requirement. It looks like I can hook into keypresses if I've got an activity running, but of course, when a notification is received, the screen will probably be off. I am looking into this currently, but I was wondering if anyone had some guidance in the meantime.
Does anyone have ideas on how I could accomplish this goal? Are there alternative ways to listen for key presses, or some creative combination of flags that could get me there?
Techniques that would normally be frowned on for Market apps are completely on the table, since the phones are owned by my employer and will only be used by other employees. I just want to avoid using private or deprecated APIs to make switching phone models easier for the developer who eventually inherits this project.
Thank you to everyone for reading!
Does anyone have ideas on how I could accomplish this goal?
You'd have to hold a WakeLock, specifically a FULL_WAKE_LOCK, in order to respond to button presses. This means that battery life will be sucktastic, unless you put some time limit on that (e.g., hold the WakeLock for a minute or two, but otherwise assume the user's not near the device, so don't keep it awake).
You would also need to try to interrupt the keyguard with KeyguardManager. I have not done this so I do not know all of the details. Your "watch for the magic button" logic would have to be in the activity that appears on top of the keyguard.
Also, bear in mind that not all Android devices have physical buttons -- in fact, I would not be the least bit surprised if the whole physical button metaphor goes "poof" with Ice Cream Sandwich later this year. Hence, the button in question really should be an on-screen Button for future-proofing.