I have a Linux audio application for Android built by NDK. The Android application is structured as follows: Java launcher launches the binary components of the Linux application and launches the X server Xsdl (http://www.tinyware.ru/hifiha/) for rendering. At this moment, the focus switches to the X server and the Android application itself goes into the background and its processes stop after 1-2 minutes. If I return to the application, then it starts working again, but I need the X server to be drawn on the screen. The power management settings for the application in MIUI do not give the desired result, but this is also reported on the Internet, which is typical for Xiaomi. Please advise what can be done about this?
Thank you.
Samsung Galaxy S6 with Android 6.0.0 and 6.0.1
My app runs fine, code analysis shows no mem leaks. SmartManager shows that the app uses ~40MB of memory. I kill the app (using the "currently running apps" overview--- not sure how that's called in English, sorry. The key on the bottom left of the phone, that shows a list of miniatures of all running apps...), then start it again.
Now SmartManager no longer shows ~40MB of memory for my app, but ... more. 50. 100. 400. It varies, but growing each time. After awhile, my app actually crashes with an OutOfMemoryException. Sometimes even with "out-of-memory while trying to throw an OutOfMemoryException"...
I have to de-install and re-install the app in order to reset its memory consumption. The same APK behaves correctly on all other phones I've tested with (e.g. S5 with Android 5.0). No idea what's causing this. No idea what could be causing this! Any help/hints/suggestions...?
Edit: Same behaviour on S5 with Android 6.0.1, but not on S5 with Android 5.0!
Edit2: Thanks, everyone who contributed. I still don't have an answer that I'm satisfied with, but a few ideas were mentioned that I will look into. Most people were focusing on the MemLeak issue, and while that sounds reasonable I'd like to stress that there is no leak occuring on Android 4 or 5, only 6. (I have yet to test 7.) Also, the leak only occurs when I forcefully kill the app (which I need to do at times to test proper shutdown and re-start behaviour), and only without a debugger attached (which makes testing/debugging this behaviour a pain in the backside).
The app starts one service as a bound service. Bound to the application context--- which according to the docs should clean itself up when the app stops.
Unfortunetely, time for this bounty is running out. So far, the above mentioned service seems to be the most likely source of my problem. As such, I will award Qamar the bounty, as he was the first to mention this both in the comments and his answer. The rest of you, a big THANK YOU and up-vote.
In Android Studio, click Android Monitor at the bottom of your screen. Click the tab Monitors. You see a graph of the memory that your app uses. Now click the item Dump Java Heap which is next to the garbage van. The system starts collecting the info and creates a dump file. You can open the file in the Analyze Tasks tab in the upper right of your Android Studio window. Press the green arrow to find classes that leak memory. When you click a leaking activity, you'll see a window Reference Tree. Go through the tree, finding the member that has depth zero. That's the memory leak.
Analyse your code and images if anything wrong you are doing itself. Like very large images of drawables. make sure you correctly implement recycler or list views.
The following links may helpful to you.
Use leakcanary library to detect and make sure there is not leaks
Detect when user kill app from reccent apps
Invoke gc from memory monitor comes with Android Studio for correct value of memory usage cause gc not run frequently.
Use large heap size. <application android:largeHeap="true" in manifest
Use app context to start servicesstartService(new Intent(getApplicationContext(),MyService.class));
Your application has some threads are timer tasks that are creating again and again and they are utilizing many resources related to networks so your heap size is consistently increasing and at sometime your app is out of memory and crashes.
Some people think that task killers are important on Android. By closing apps running in the background, you’ll get improved performance and battery life – that’s the idea, anyway. In reality, task killers can reduce your performance.Android isn’t Windows and doesn’t manage processes like Windows does. Unlike on Windows, where there’s an obvious way to close applications, there’s no obvious way to “close” an Android application. This is by design and isn’t a problem.When you leave an Android app, going back to your home screen or switching to another app, the app stays “running” in the background. In most cases, the app will be paused in the background, taking up no CPU or network resources. Some apps will continue using CPU and network resources in the background, of course – for example, music players, file-downloading programs, or apps that sync in the background.When you go back to an app you were recently using, Android “unpauses” that app and you resume where you left off. This is fast because the app is still stored in your RAM and ready to be used again,hence consuming no further resources.
Task killers like smart manager think they know better than Android. They run in the background, automatically quitting apps and removing them from Android’s memory. They may also allow you to force-quit apps on your own, but you shouldn’t have to do this normally.If a task killer removes an app from your RAM and you open that app again, the app will be slower to load as Android is forced to load it from your device’s storage.Further s6 has Smart Manager and could be used as a widget or shortcut to battery and storage settings,however you should avoid using the Clean All optimization feature. This feature is said to improve device performance – as the Clean Master app aims to do – but its actual impact is questionable.
Meaning while still sometimes you kill an app it can still leave the traces on heap so next time when you start it ,it will show varyingly more amount of storage used which also fails the notion of default maxMemory() and the app ultimately might crash.Further such leaks are difficult to track as they aren't directly associated to app you killed in first instance.But still sometimes even after killing app, certain features like resources attained may keep running in background without even the app even knowing about them.i.e unnoticeable leaks.Thus you may want to use maxMemory()
which can be invoked (e.g., in your main activity's onCreate() method) as follows:
Runtime rt = Runtime.getRuntime();
long maxMemory = rt.maxMemory();
Log.v("onCreate", "maxMemory:" + Long.toString(maxMemory));
This method tells you how many total bytes of heap your app is allowed to use.
Optimal Behaviour:
An app can stay "running" in the background without any processes eating up your phone's resources. Android keeps the app in its memory so it launches more quickly and returns to its prior state. When your phone runs out of memory, Android will automatically start killing tasks on its own, starting with ones that you haven't used in awhile.
What You Should Do Instead
That said, not all apps are created equal. Many of you have used task killers in the past and actually found that after freeing up memory, your phone works a bit better. It's more likely that this is because you've killed a bad app that was poorly coded, and (for example) keeps trying to connect to the internet even when it shouldn't. Any performance increase you experience is more likely because you killed the right app, not because you freed up loads of memory (or, in many cases, it's just placebo). Instead of killing all those apps, find out which ones are actually causing the problems.using a task killer to deal with a misbehaving app is like using a shotgun to kill a fly – you may fix your problem, but you’re inflicting a lot of other damage in the process.Now
since S6 has 3 gigs of ram,it should'nt have problems,however implementation of smart manager can cause problems with some apps and isnt necessarily android version dependent.Also bare that heapsize tends to be based more on screen resolution, as higher-resolution screens tend to want to manipulate larger bitmaps.
Instead of using a task killer in this situation, you should identify the bad app and uninstall it,or debug it, replacing it with an app that works properly. To pin down the app that’s misbehaving, you can try the
Watchdog Task Manager app
– it will show you which apps are actually using CPU in the background, not which apps are harmlessly being stored in memory.
Captivating Fact:
CyanogenMod, the popular community-developed Android ROM, won’t even
accept bug reports from users using task killers, saying that they
cause more problems than they solve.
A probable cause of issue
if you can try following at once,first of all go to settings >sounds and notifications > App notifications > select smart manager and select hide content on lock screen
then again back to settings go to lockscreen and security >Device security >Disable KNOX active protection and deactivate the anti malware option below KNOX active protection
in lock screen and security go to other security settings > disable send security reports and go down to ussage data access> disable smart manager so after that restart your device.Now see if the app works Also see performace concerns with s6
I'm new in Android developing (I'm a developer iOS from 3 years) and the very first thing that I notice in Android is that when I install my app from Android I need to unlock the screen manually.
This might seem like an unimportant thing but very often I'm wait in front of the screen for a few seconds and then I realize that I have to unlock the device manually.
Thanks
Well, I don't know about auto unlock but you could set "Stay Awake" in developer settings on your phone. This means the screen will not lock when you are connected to your computer. Not compatible with all phones due to some screen types.
Also, you could have a scout around the Play Store. There are numerous attempts at this but with varying results I suspect.
--Conor
I'm quite new to Android programming but familiar with C/C++ and Linux enough to program a few stuff. In my next project, I've to run some native application (Linux applications) under Android.
The executable I'm calling is using the framebuffer device to produce screen output. When I try to just call the program the output of the program is lost because Android is redrawing the screen, thus overwriting the framebuffer.
In order to prevent this, I made a "stubbing" Android program, which actually has no window design (just a black screen) but calls my program. This is working good to some extend; however, whenever I rotate the screen, or some Tattoo notification comes, Android redraws the screen and we're back to frame #1...
Thus, I wondered if there is a "low level" API or something, which can prevent Android from using the screen at all, as long as I release it. Shortly, like a WakeLock preventing phone from sleeping, I want a 'Lock' which will lock the screen (framebuffer device) completely. Does anyone know how can I achieve such functionality?
PS: This might have something to do with SurfaceFlinger, but I've read somewhere that it doesn't publish any API to user-level.
On Android the screen belongs to SurfaceFlinger.
The executable I'm calling is using the framebuffer device to produce screen output.
That's not supported.
Thus, I wondered if there is a "low level" API or something, which can prevent Android from using the screen at all, as long as I release it.
Nothing that is supported at the SDK or NDK levels. You are welcome to create your own custom firmware that does whatever you want, and load that custom firmware on your own device.
Otherwise, please use a supported means for interacting with the screen (e.g., OpenGL natively in C/C++).
i am new to android development and had question regarding custom screen saver.
The requirement is for a tablet which will always be plugged in so battery life wouldn't be
an issue. The required app should behave as a screensaver in that during inactivity, the tablet should launch this app which contains a flash file that displays a series of images and video. When activity is resumed then the tablet takes the user back to the program they were using.
Can this be done via an app without requiring any hacks?
cheers,
abhi
There is no concept of a "screensaver" in Android.
There is the lock screen, which can be modified via custom firmware, though AFAIK it is implemented in Java as part of the OS and therefore could not be replaced via a Flash APK.