HP Prime Android Application (2016.12.08 1.3.1.11226) is clearing user apps/programs

[kharpster]

I am having a problem with the latest version of the HP Prime Android app. When I create an application (Graph3D) it works for a while and then totally disappears from the calculator (the app and the program).

Hardware:

Moto Droid Z
Android 7.0
Kernel: 3.18.31-perf-g174cc6c

Again, this issue did not exist prior to installing the latest version from the play store on the same device configuration. I also uninstalled the HP Prime app and did a fresh install, this helped a bit, but the problem still exists.

Update:

There seems to be a correlation between clearing recent apps (Square Button on phone, then swiping the app or doing a 'Clear all') and the deletion of any/all user application/program(s) within the HP Prime. And again, this behavior did not exist with the prior version of the HP Prime app on my current device/os.

[Tim Wessman]

Thanks. I will investigate.

Do you mean you open the "Recently run applications" screen that shows running apps, and do a "close" on it?

[kharpster]

Tim, yes closing the Prime app when viewing the "list" of recent apps on the device is what I mean. Additionally, it usually takes several attempts to deliberately cause the issue. I suspect the problem occurs when the OS actually kills the Prime App and removes it from memory. Since reporting this issue I have also had the Prime App crash a couple of times while running in the background, and sent in the logs. Something definitely changed with the persistent storage of user created apps/programs on the Prime (maybe mismatched write/read locations).

[Jan_D]

Maybe it is necessary to close the Prime correctly by pressing Shift - On, and only after having done this clear the app as you would clear other apps.

At least I noticed that after the update Shift - On has another effect than before.

It blackens the part of the app which is the screen of the physical calculator, and leaves the keys white.

Before the update doing this same thing closed the app.

[Terje Vallestad]

(12-19-2016 06:17 PM)Jan_D Wrote:  Maybe it is necessary to close the Prime correctly by pressing Shift - On, and only after having done this clear the app as you would clear other apps.

I have noticed the same for iPad/iPhone. Restoring from a back up and then killing the app would reset it to factory default. Doing an "off/on" cycle seems to prevent this.

Cheers, Terje

[kharpster]

I tested, and doing an on/off cycle had no effect, issue remains the same. Also, the app is not being reset, just the app/program data are wiped. Additionally, I created an app, powered off the phone, powered on the phone and the app was still in the HP Prime. But closing the app as described in my initial post eventually erased the user app and program from the Prime emulator. The new version is also unstable on 7.0 and has crashed more than once, this did not happen on the prior build with 7.0.

[ggauny@live.fr]

I see an issue with version 11226 when I use FREEZE instruction in Virtual HP Prime on the pc wind10.
For one second the graph appears and immediately deasappears. In 10638 (and earliers versions) no problem.

[Jan_D]

(12-18-2016 12:24 AM)kharpster Wrote:  I am having a problem with the latest version of the HP Prime Android app. When I create an application (Graph3D) it works for a while and then totally disappears from the calculator (the app and the program).

Hardware:

Moto Droid Z
Android 7.0
Kernel: 3.18.31-perf-g174cc6c

Again, this issue did not exist prior to installing the latest version from the play store on the same device configuration. I also uninstalled the HP Prime app and did a fresh install, this helped a bit, but the problem still exists.

Update:

There seems to be a correlation between clearing recent apps (Square Button on phone, then swiping the app or doing a 'Clear all') and the deletion of any/all user application/program(s) within the HP Prime. And again, this behavior did not exist with the prior version of the HP Prime app on my current device/os.

I have seen the same thing happen, with Android 4.4.2!

Before the update it was the contrary: it was by no means possible to delete a custom app, even if you wanted it.

I did not regret this though, because in cases of crashes, when all other apps lost their content, the custom apps kept it.

This is more serious, I hope that this does not happen to programs!
Maybe I will have to try to install the previous version again, I made a backup.

[Jan_D]

I just tested what happened to programs in cases of crashes, which happen frequently when just starting and clearing the app as described by Kharpster.

It turns out that also all programs are deleted.
This did not happen before the update. Programs were never deleted in cases of crashes.

I do not think that I will write a program yet in this situation, only for being deleted in the next crash.

[Jan_D]

I have not seen problems yet when I consequently close the Prime with Shift -On.
Only the risk is too big that one crash can possibly delete all my programs.

[Tim Wessman]

So basically what is happening here is that there is the idea of "persistent bits" in the Core calculator code. This is from the calculator hardware, where it sets bits in the processor on boot at certain stages. If certain bits repeat, it will attempt to bypass loading files, some other troubleshooting things, or in a final case "erase" the disk. Basically, it is a fail safe to prevent the user from getting stuck in a boot loop.

This was previously not implemented in the android app and occasionally users would report having to "uninstall and reinstall" to fix things. However, it seems that something is not happening as expected. Currently, it is using a small file on the disk to keep this "persistant bit" information. I suspect that the file isn't being written out to flash because of an OS caching mechanism. When you force close the application, the file is not being written out before hand.

A "shift-off" will "save" the files currently in the calculator which explains why you see that. If you changed your "TOff" value to something smaller, this would also happen when that is called as well. In addition, it is supposed to call this when you press home in the task switching calls. However, opening the "force kill" screen might not be saving things...

Android/iOS are new to the HP Calculator group in many ways, and certain things like this are bound to pop up unfortunately as we encounter some of platform specific quirks.

[switching over to technical discussion here - you may want to stop if not interesting to you... ]

So a more technical question for anyone with android development (w/NDK) experience...

What would be the appropriate mechanism for storing some information that must persist permanently between application runs *used within the NDK*? On first glance, I wanted to use a SharedPreferences object. However, that seemed overkill and has no simple way to access from the NDK side of things, so I thought a simple file read/write would be the way to go. Suggestions?

[Jan_D]

I have a central “Home” button.
When I press it the Prime is closed and I go to the desktop of my tablet where I see all my apps.

I have tried this to close the app instead Shift - On (=Off).
When I do this and next remove it from my list of recent apps, or close all recent apps, it causes the same problems as directly removing it from my list of recent apps, which Kharpster described, when I am not mistaken.

I have to repeat the cyclus of closing and starting about 3 times to cause the crashes.

Closing with Shift – On keeps giving no problems.

Unfortunately I can not help you with technical solutions!
I would prefer the situation before the update in this respect.
The addition of sound and vibrational feedback is an appreciated improvement.

[kharpster]

(12-21-2016 08:12 PM)Tim Wessman Wrote:  What would be the appropriate mechanism for storing some information that must persist permanently between application runs *used within the NDK*? On first glance, I wanted to use a SharedPreferences object. However, that seemed overkill and has no simple way to access from the NDK side of things, so I thought a simple file read/write would be the way to go. Suggestions?

Tim,

Not being an NDK developer, but having written a line or two of code in my life, two options come to mind. Use a SharedPreferences object and JNI to read/write it in native. Or as you've stated, fwrite/fread a small file from native. I am curious as to how you are writing the data currently and if you are doing a sync() or another form of write-through on the cache.

In the interim, this update has caused considerably more problems than it has solved, not the least of which is it constantly crashes and takes any app/programs with it. Can we get the prior version back in the store until this build is stable? To that end, I would be happy to assist with future beta testing.

[Jan_D]

At the moment I am trying to generate voluntary a crash, while I am closing all the time with Shift – On.
I have no success so far.
A way which would certainly do it in the previous version does not do it anymore (bug solved).
Then I thought writing an endless loop might have success, but pressing “On”, or Shift - On easily gets out of it.

[Jan_D]

I have come across my first situation in which pressing any key gave no reaction anymore.

I pressed the “back” button on my tablet, and then started the Prime again.

As usually the history of Home view and Cas had lost the work of the last session, but for the rest nothing had gone.

So not very serious.

[chromos]

Nexus 6 phone with Android 7.0

I tried more than twenty times "switch-off" my HP Prime with triangle or circle softkeys without [Shift] [On] and no strange behaviour. No data loss or anything else after killing HP Prime at running apps in "square" menu of the phone. But after rebooting my phone I lost everything from the calculator including Settings. It seems the calculator is in factory default state after reboot. This is not much good for any work. :-(

[Jan_D]

Another serious issue,

Pressing the "back" button of my tablet, in a situation where everything is normal, closes the Prime as expected, but restarting the Prime after this deletes everything, so also all programs.

This seems unacceptable to me.

[didda]

Same problems as kharpster with HP Prime (Version 2016 12 08 11226) on my Samsung Galaxy S5 (Android 6.0.1).

With Update 11226 the Prime hangs and/or crashes very often, programs! and settings lost.

This App is not usable! 

Please let me know if the problems depends on specific Android-Version (Sw/Hw) or may this is a general HP Prime problem (on Android)? 

[Jan_D]

As I said in my previous post, pressing the “back” button of my tablet in order to close the Prime, and after this start it again causes loss of all content.

In the previous version it was the opposite.
Regularly pressing the “back” key which closed it, was one of my ways to save content, when I did not want to loose it in a crash.

[Jan_D]

(12-20-2016 08:10 AM)ggauny@live.fr Wrote:  I see an issue with version 11226 when I use FREEZE instruction in Virtual HP Prime on the pc wind10.
For one second the graph appears and immediately deasappears. In 10638 (and earliers versions) no problem.

It is not really the subject of this thread, but I just wrote a program which uses FREEZE, and have no problems with this on Android 4.4.2.