My LogCat is often not showing null pointer exceptions..
Sample:
ProgressDialog pd;
ps.show();
Application stops (do not reacts for any action), but there is no information about any reason in logcat.
Another sample is with database - if there is no DB and I'm making actions on it, the same happens.
I tried (that action with DB) on my colleague's phone and there was normal error. I have all needed programmer options in my phone turned on.
Maybe someone know , why it is so? It was not burdensome, when I had small app, but now when it's bigger, it can be really frustrating.
I get this with android studio too...
Close android studio, restart ADB, and generally it starts working for me.
If that does not work then put a breakpoint at the line .show(); ... Then open up the logcat and then skip over the breakpoint. It then shows, I have similar issues.
(Windows 7 64 bit - Android Studio 0.82)
I dont like the IDE logcat option honestly.
The SDK comes with an adb binary, use the logcat option from there via
adb logcat or my personal favorite built in alias, adb lolcat
This will give you the log information for EVERYTHING happening on the device, and can be useful tracking down issues caused by device state.
For example, you can see network changes in the logcat, and if your app crashes on network call you wouldnt have any idea why if you just used the logcat output from your app.
In my case I was using: Thread.setDefaultUncaughtExceptionHandler in my application file. If that is not turned off during debugging you won't see any exception output. ( Just make sure to turn it back on again when you release so you can still handle your issues ).
Related
Sometimes when a phone connects to Android Studio, it will print logs between the time it was last connected to Android Studio and the present. This is cool, but I can not replicate it. Some times it happens, sometimes it does not.
I have a guess that this is a feature of USB and wireless debugging, and that logs are put in a temporary file so they can be sent to logcat when reconnected. If so, how do I keep the USB debugging from turning off when testing my device in the field during the day, so I can get the logs that were printed during the day? If not, what is happening?
The logs are nothing to do with Android Studio (or logcat in general) - it's just system logging happening on the device, and that happens whether it's connected to a log-reader or not.
At a guess, what's happening is your app's process is being closed, so the next time it runs it gets a different PID (process ID). When you connect it to the computer, your dropdown shows the currently running app process, and filters by its PID, so you don't see the old stuff.
You've probably seen this while debugging - if you re-run your app, the log "clears" and gives you a fresh one for the new run of the app. The old log messages are still there (as well as a hell of a lot of other logs for all the stuff going on on the device - it is noisy), it's just that you can't see them.
The simple thing to try is going to the filter dropdown on the right of the logcat window, and choose No filtering. Then in the filter query thing next to it (with the 🔎) type the name of your app, maybe its package. It's not perfect but it should show you all of the logs it has from your app, along with a bunch of system stuff that's also referring to it. You could get clever with PIDs or setting up a custom filter in the dropdown to get better results.
You might also be interested in the guide (with some filtering tips) and the commandline version if that's more useful to you
In my limited experience on a handful of Android devices, if an app crashes with an unhandled exception then that exception's written to the log. However I've come across a Samsung i8160 that doesn't. Other i8160s with various ROMs do. In fact, from boot, it doesn't log anything. It originated on eBay so the history is unclear, but rather than assuming it's an odd ROM and flashing something else I figured it was worth persisting in case the problem arises again elsewhere.
In researching, the first thing to try was to 'dial' *#*#2846579#*#* but this isn't recognised- it just tries to really dial that. There's a shorter *#9900# that does pop up a menu, but that only lets me dump the log and other info to files in /data/log for export. Since logging isn't up from boot, that doesn't export much.
Initially, /dev/log doesn't exist. One suggestion to fix this was to try logcat-enable from a shell. This isn't found. Another suggestion was to manually load the logging module by running insmod /lib/modules/logger.ko from a rooted shell. This brings logging up, but when an app crashes, all logcat outputs is
I/dumpstate( 8074): begin
I/dumpstate( 8074): done
I've found the dumpstate files, which include the logcat output, but there also it just notes creation of the dumps, not the exception that caused it.
As well as starting the module, I'm assuming somewhere there's some configuration determining what actions to take when an app crashes, and here it's not set to dump the exception and stack trace to the log because whoever did it figured logging wouldn't be running anyway. But I can't find anything like this. Does anyone have any ideas on how to progress further?
Some apps have a "report" function inbuilt in case their app crashes. When you choose report on the ANR message, usually a log is created for sending it to the developer. Maybe you can get an app to crash and catch that log (or maybe make your own one)
I'm trying to debug an application that I'm writing using Android Studio but I can't seem to get any useful debugging information out of Android Studio's "Debug" view. I'm launching my application with the bug-looking "Debug" icon but the "Debug" view doesn't have anything useful (no stack frames from my application, for example):
Even if my application crashes I don't get any useful information. As I recall, the ADT plugin would automatically drop you on the line that caused the crash.
Do I need to do anything else to make my application "debuggable" in Android Studio? I've also tried forcing android:debuggable="true" in my AndroidManifest.xml but to no avail. Android Studio does seem to be attaching to the running process (the app shows the "attaching to debugger" message for a few seconds when it first launches).
There are some things to check:
If your app-debugger is working and stopping on normal breakpoints, maybe you have to set an exception-breakpoint:
Open Debugger
Press "View breakpoints"
Usually, there should be a breakpoint called "Any exception" with checkboxes on "Caught exception" and "Unchaught exception". If not, add an exception breakpoint yourself and specify the type(s) of exceptions you want the debugger to stop on (you can use wildcards in the exception-classnames, e.g. *Exception).
If your app-debugger is not working, check the following options:
Check if you have enabled USB-Debugging in the developer options of your device
Check if you have authorized the computer as a development machine in the developer options of the device (if unsure, clear the authorization-list from the developer options page and reconnect the device)
Check if your development machine has only one adb-server-process running in the background (if more, kill all of them with a process mananger and restart with "adb start-server")
Add "debuggable true" to your debug-buildType in build.gradle:
buildTypes {
debug {
debuggable true
}
...
}
If your app-debugger is still not working, restart your computer and re-install adb-drivers for your device. Make sure there are no conflicting drivers active with more than one connected device (maybe connecting only one at a time).
Note: even if you got exception breakpoints working, they might not be useful at all, depending on the type of the crash. Most of the times, you will get the debugger stopping in the Zygote-exception handler where you don't get much useful information or stacktrace.
In such cases, it is the easiest to just let the debugger resume or reproduce the crash without a debugger, and check the logcat-output for a stacktrace in the ERROR-loglevel of your app's logcat-output. Those stacktraces should have clickable line-infos thus enabling you to set a normal breakpoint on a relevant line of code in your app's source code to analyze the problem.
After updating Android studio this problem went away. Not sure what the issue was.
My application throws an error when I attempt to start it from "Recent applications". Problems :
Error appears only if application was inactive (stopped) for a long time (approximately one hour). I can't catch this error by myself - when I'm killing process by myself and then relaunched it there is no errors!
I can't see Exception log in debugger, since it's disconnects after so long time.
How can I catch such kind of errors in debugger? Looks error appears only when OS kills application by itself.
EDIT
I didn't overrided onResume method. Just onStart, and there is nothing special except instantination of my SQLiteOpenHelper.
even if your app is in paused/stopped state, log cat will still be working as long as device is connected. make sure you selected all logs options in windows > devices > all logs instead of windows > devices > com.your.project .
so when you will try to relaunch crash must be recorded in logCat
if still have any issue, install logcat app from market and refer it for logs.
Sounds like there might be an issue in your
OnResume
call. What is your application doing? Is it using a location manager? Does it have services or threads that need to be restarted? More infomation please.
Look through the Android application lifecycle chart:
http://developer.android.com/reference/android/app/Activity.html
It should help you understand what's going on. If all else fails, add a lot of logging to logcat and see what the output looks like on your end. As long as you don't unplug the device, you shouldn't lose that in Eclipse. If you do, you can always run "adb logcat" from the command line or shell to see exactly what's happening.
I'm developing a first app for android, and I sometimes get a message "this application stopped unexpectedly" and a "close" button.
How can I find out what's wrong? When the phone is connected to the computer, it would show in the Logcat of Eclipse, but my phone is not always connected to my computer. How do you handle that? How do you handle the error reporting in your app when it's not in debuggable status?
How can I configure my app to restart in such an occasion? I have an other app (not developped by me) which sometimes shows the message that it restarted after memory low (or something like that). I'd like to restart my app too when, for whatever reason, it crashed.
Anybody?
I am not sure about the second question but for the first part you can run adb logcat in background. for that just go to the folder location where adb.exe esixts, in command prompt and just type
adb logcat > /data/log.txt &
it will run in the background and store the logs in log.txt file. When you are done with your force close. just type following command
adb pull /data/log.txt .
it will extract the logs, and will put in the current directory location, you can open it using any text editor.
If your device is not connected to a computer, you can see the logcat output using the following app: aLogcat
Also, I'm not sure that restarting an app that has just crashed is a good idea. This could lead to an infinite loop of crashing/restarting.