I'm wondering if there is anyway to handle an application crash. By that, I mean if we can detect a crash and when it occurs save some data, because I need to save some values into a SharedPreference if the application crashes.
Is this possible?
Yes there is an open-source project for reporting or handling the crash report. try this link
ACRA
You Can Use Try...Catch...finally block to Catch Exception and when Exception occurs finally block content definitely works even exception handled or not.
Related
I'm building an app that sometimes crashes, I want to know that it crashed in the next time I opened it so I can suggest to the user some post-crash options.
How can I detect the crash?
Also I want to be able to save the user's work before it crashes, I means real time detection of crash, can I do it without knowing where it crashed?
You will need to know where it crashed in order to set the try/catch blocks in the right place to, er, catch the crash and save the data or whatever you have in mind.
This is known as "graceful" termination if you want to consider it in more detail.
Unfortunately neither Java destructor/finalize methods nor lifecycle methods such as onDestroy are anywhere near as robust as try/catch blocks so I'm afraid that is your only option, and how many of us deal with exception prevention. No-one would wittingly provide a user experience that crashes, much less with loss of their data.
Take a took at the ACRA library. You can configure it so whenever a crash happens you can control it and even send the crash log by email
You can use try/catch blocks, then send details on the Exception in your catch.
There are implement UncaughtExceptionHandler as mentioned in these answers and write crash report in some file or use it another way.
ACRA is already mentioned.
However for paid version, I found BugSnag is very good at this.
Or if you want to take the extra mile, try AppSee.
AppSee even has video recording session of how the crash happens. It is from tapping that button on the second list, the menu button or even when the user slides left in your viewpager.
What is the usual way on Android to stop my application if it has reached an unrecoverable error.
finish() will not do it, since it wont stop any running services or threads. Furthermore I would like to inform the user what has happend and please him to send an error log.
As far as I googled, it seems like there is no way to close my application and open a special crashreport activity or something else to show the user whats going on or send a crash log.
I think you should throw unhandled runtime exception. In such case android will kill all your process. Also I suggest you to use ACRA. This library will help you to get crash report (via email, google docs, etс.) and it can show customizable error dialog to a user.
You should check this out. This could be your solution.
ACRA
Check the basic setup guide to start using the library. ACRA - Basic Setup
While ACRA is an okay solution, if you want to implement your own logging of unhandled exceptions try Thread.setDefaultUncaughtExceptionHandler(). That way you can get any exceptions that are thrown and not caught, and log them the way you like. You need to implement Thread.UncaughtExceptionHandler and pass it to that method.
With an Activity, it would look something like this in onCreate():
getMainLooper().getThread().setUncaughtExceptionHandler(new MyUncaughtExceptionHandler());
I know what causes a NetworkOnMainThreadException, as well as how to fix it, but for the purposes of improving the development experience, I'd like to be able to catch the exception and at least log the event or alert the user (who is still the developer at this point)...
Strangely, I'm not having any luck with this code (which sends and receives over my TCP socket):
try
{
toServer.println (msg.trim());
resp = fromServer.readLine();
}
catch (android.os.NetworkOnMainThreadException nex)
{ ... do something here ... }
Eclipse doesn't recognize that exception at all, and I copy-pasta-ed the exception type from the Android Developer website -- I'm pretty sure I spelled it right...
Is there something I don't know about Java (perhaps) that makes this exception uncatchable??
Thanks,
R.
Is there something I don't know about Java (perhaps) that makes this exception uncatchable??
Yes, StrictMode makes it uncatchable. Either way though, you should not catch this exception. Instead, you should implement your code correctly by wrapping your code in an AsyncTask. The reason why this exception is thrown is to prevent you from slowing down your application by blocking the UI thread.
Read my blog post for more info:
Why Ice Cream Sandwich Crashes Your App
Well I just tested this on my version of eclipse, and it works just fine.. I guess I would check which version of the api you are using? looks like to throw that exception you need a minimum api version 11. Otherwise perhaps eclipse is to blame? All I know is that this code is correct and should be executing without any issues.
Are you sure this is the first use of networking in your application?
If you are connecting to a server usually at that time NetworkOnMainThreadException should be thrown. Try adding a log statement before the try and see if it shows up. If it does not the Exception is thrown earlier.
In my android app I need a global exception handling mechanism. That is an exception handler which works when an exception occurs from any activity of my app. Is this possible? How?
if you have access to your own web server with PHP installed, you might have a look at this
http://code.google.com/p/android-remote-stacktrace/
The Google Groups thread they're pointing you to is a good reference. I have a helper class in my app that offers the user the option of sending a failure report to me with the details of the crash. Basically, when the failure is caught it writes the details out to the SD card and on next run of the app it displays a pop-up.
It won't keep your app from crashing, but it will let you do something intelligent with result.
I have some required try/catch statements in my application that in my testing never get called. I have sent them up with:
Log.e("messaage", e.toString());
for my debugging and now that I'm ready to release I am not sure if I should take that out or not. I see in android market you can get error/crash reports and while I do not expect my app to catch any errors, I would like to know if that happens and wondering if I need specific syntax for that. My question is what should I do in the catch statement for these errors? I'm already handling the error from a user standpoint...
Thanks!
IMHO logging is not really necessary, but sooner or later you will catch something. Acra may be of interest to you, if you want to be notified of these occasions.