Android Logcat is empty when debug with device in android studio

Question

When I try to debug using android device in android studio Logcat shows nothing. But when I use emulator LogCat shows all the messages. How should view the Logcat messages when debugging on actual device?

Thank You !

Answer 1

In Android studio 0.8.0 you should enable ADB integration through Tools -> Android, before run your app. Then the log cat will work correctly. Notice that if you make ADB integration disabled while your app is running and again make it enable, then the log cat dosen't show anything unless you rebuild your project.

Answer 2

As of 0.4.0 I have noticed that the logcat tab does not work in the debugger window - only in the Android DDMS window (hit Alt+6 to bring up the working logcat while debugging). Awkward I know :)

Answer 3

Restart the phone. And it solves magically

I was using Lenovo A7000plus powered by Android 6.0 M and found out that my Android Studio was unable to record the debug process, but somehow other's phone debug report could be recorded. Plus, I tried use Memu emulator and it recorded normally.

Strangely, that device was recognized by Android Studio and ready to be debugged, but no recorded debug report at all from all application that ran on the device. Of course, USB debug was tuned on.

What I did before, I turned off Developer option on that phone in order to play my favourite mobile game (F/GO) which forbids USB Debugging is turned on in the device.

A few hours later, after trying any method in Internet and not success, accidentally I found simple but strange solution that is Restart the phone . I restarted the phone while it was connecting to PC, and somehow the logcat showed all debug process in Logcat like normal.

It sounds like non-engineering solution at all, but that's really work for my case.

Answer 4

在Android studio 1.0.2或更高版本中：在运行应用程序之前，您应该通过工具 - > Android 启用ADB集成

Answer 5

In Android studio 1.* if logcat messages have disappeared for me helps the next trick:

Tools -> Android -> disable )) "enable ADB integration" (if it've been enabled)
Tools -> Android -> enable it again "enable ADB integration"

Answer 6

In 0.8.2 the DDMS window doesn't show up. However restarting the adb logcat windows by pressing Alt+6 (Twice, if it's already opened) fixes the issue. It worked for me.

Answer 7

I understand that this question is over 2 years old, but from my searches a few people are still having a persistent problem with this. One possible solution to this (which worked for me after two hours!) is that your phone settings may have its "Log Switch" set to off, hence it isn't sending your log data to the IDE.

Here is the solution - "Unable to open log device '/dev/log/main': No such file or directory"

Hope it helps!

Answer 8

如果有人在这里尝试所有答案仍然遇到问题，只需使用System.out.println而不是log。*，您的调试消息将输出。

Answer 9

Updated: I finally got the cause of the problem in my case. If I switch of my device's wifi, the log shows. Otherwise, the log will not show. I tried several times and it the always show full logs when I turn off my wifi.

My device is: Gsmart Classic, OS: Android OS, v5.1 (Lollipop). I met the problem when I updated the gradle build tool from 'com.android.tools.build:gradle:2.0.0-alpha1' to 'com.android.tools.build:gradle:2.0.0-alpha3' in Android Studio 2.0-preview. After trying all the solutions with no luck, I tried un applied all the instant run choices and re-apply it again. Then the logs show up.

Note: if it still doesn't help. You can as well try to switch back-and-forth the back ground process limit. Unfortunately, I couldn't reproduce the error.

Answer 10

In Android Studio 2.x I used to have to restart to get it working but often switching back and forth between the applications works or running

adb kill-server; 
adb start-server;

to restart adb fixes many things as well.

Answer 11

The problem seems to have different causes.

For me, the issue was that I had two emulators with the same name (I created it, deleted it, and then created it again with the same name). There were two emulator entries in the logcat dropdown and it was connected to the wrong one. All I had to do was switch to the other one. I prevented the problem permanently by renaming the emulator.

Answer 12

I believe that the problem has various causes for different users. I experienced the same issue with logcat not displaying any information when my application crashed, and we all know how frustrating this can be.

The following are the solutions that worked for me.

• Invalidating caches and restarting android studio
• In the developer option in your physical device make sure the logger Buffer size is set to 1MB per logger buffer.
• Restart your physical device.

Hope this helps.