Android - Print Full Exception Backtrace to Log

Android - print full exception backtrace to log

try {
    // code that might throw an exception
} catch (Exception e) {
    Log.e("MYAPP", "exception", e);
}

More Explicitly with Further Info

(Since this is the oldest question about this.)

The three-argument Android log methods will print the stack trace for an Exception that is provided as the third parameter. For example

Log.d(String tag, String msg, Throwable tr)

where tr is the Exception.

According to this comment those Log methods "use the getStackTraceString() method ... behind the scenes" to do that.

How to print stacktrace for an exception Android

} catch (IOException e) {
    Log.e("YOUR_APP_LOG_TAG", "I got an error", e);
}

And check the LogCat for the output.

Java / Android - How to print out a full stack trace?

There's overrides of all the log methods with (String tag, String msg, Throwable tr) signatures.

Passing an exception as the third parameter should give you the full stacktrace in logcat.

Throw an exception and print its stacktrace in the logcat at error level

Try adding to your else statement

Log.e(TAG, "mymessage",e);

Whole code:

@Throws(RuntimeException::class)
fun throwErrorIfNotHttp (e: Throwable) {
    if (e is HttpException) {
            val code = e.code()
    } else if (e is SocketTimeoutException) {
            Log.e(TAG, "time out")
    } else if (e is IOException) {
            Log.e(TAG, "file error")
    } else {
      Log.e(TAG, "mymessage",e);
      throw RuntimeException(e) // This  should appear as error
    }
 }

companion object{
  val TAG = "class_tag"
}

Where do I see printed stack trace in Android Studio?

Stack trace will be send to default (console) output. In Android Studio (which is based on IntelliJ idea) is that window called logcat.

@See image below.

If you can not see this tab, go to Window > and click Restore Default Layout
You can click Shift + F12 as well.

incomplete backtrace in logcat

The answer appears to be to upgrade to Android 4.3. My phone received an update today (the custom HTC version rolled out to developer edition devices) and the backtraces dumped to the system log now reveal a full stack. However, as @user1034749 suggests, getting to grips with GDB is a good alternative with many additional benefits.

e.printStackTrace(); in string

Use the following piece of code:

Writer writer = new StringWriter();
exception.printStackTrace(new PrintWriter(writer));
String s = writer.toString();

There used to be a way to extract an exception stacktrace into the String in one line with Log.getStackTraceString call. But starting from Android 4.0 (API 14) that method is not reliable anymore, as it returns an empty string for UnknownHostException (see Android issue #21436 for the details, in short: "to reduce the amount of log spew that apps do in the non-error condition of the network being unavailable" Android engineers made IMHO a dubious decision to modify Log.getStackTraceString method).

Thus it is better to use the code I provided at the beginning of this post.

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