Enabling log in PJSIP for Android forces close the app

问题

I'm building a SIP Softphone using PJSIP for android based on SWIG example.

I enable log as described in the sample:

LogConfig log_cfg = epConfig.getLogConfig();
SipLogWriter logWriter = new SipLogWriter();
log_cfg.setWriter(logWriter);
log_cfg.setDecor(log_cfg.getDecor() & ~(pj_log_decoration.PJ_LOG_HAS_CR.swigValue() | pj_log_decoration.PJ_LOG_HAS_NEWLINE.swigValue()));

where my SipLogWriter class is:

public class SipLogWriter extends LogWriter {
    @Override
    public void write(LogEntry entry) {
        Log.d(Global.TAG, "[SipLogWriter] " + entry.getMsg());
    }
}

Pjsip lib halts every now and then with this backtraces:

05-04 10:32:10.534 I/DEBUG   (  281): backtrace:
05-04 10:32:10.534 I/DEBUG   (  281):     #00 pc 00037b58  /system/lib/libc.so (tgkill+12)
05-04 10:32:10.544 I/DEBUG   (  281):     #01 pc 00013fc9  /system/lib/libc.so (pthread_kill+52)
05-04 10:32:10.544 I/DEBUG   (  281):     #02 pc 00014be7  /system/lib/libc.so (raise+10)
05-04 10:32:10.544 I/DEBUG   (  281):     #03 pc 00011529  /system/lib/libc.so (__libc_android_abort+36)
05-04 10:32:10.544 I/DEBUG   (  281):     #04 pc 0000fcb4  /system/lib/libc.so (abort+4)
05-04 10:32:10.544 I/DEBUG   (  281):     #05 pc 00001259  /system/lib/libstdc++.so
05-04 10:32:10.544 I/DEBUG   (  281):     #06 pc 00000afb  /system/lib/libstdc++.so (__cxa_pure_virtual+6)
05-04 10:32:10.544 I/DEBUG   (  281):     #07 pc 0015d4e8  /data/app/com.sample.app-1/lib/arm/libpjsua2.so (pj::Endpoint::utilLogWrite(pj::LogEntry&)+180)
05-04 10:32:10.544 I/DEBUG   (  281):     #08 pc 0015d734  /data/app/com.sample.app-1/lib/arm/libpjsua2.so (pj::Endpoint::logFunc(int, char const*, int)+292)
05-04 10:32:10.544 I/DEBUG   (  281):     #09 pc 001a9fe0  /data/app/com.sample.app-1/lib/arm/libpjsua2.so (log_writer+164)
05-04 10:32:10.544 I/DEBUG   (  281):     #10 pc 0034420c  /data/app/com.sample.app-1/lib/arm/libpjsua2.so (pj_log+2324)
05-04 10:32:10.544 I/DEBUG   (  281):     #11 pc 0034436c  /data/app/com.sample.app-1/lib/arm/libpjsua2.so (pj_log_4+44)
05-04 10:32:10.544 I/DEBUG   (  281):     #12 pc 0025c9c4  /data/app/com.sample.app-1/lib/arm/libpjsua2.so (play_cb+568)
05-04 10:32:10.544 I/DEBUG   (  281):     #13 pc 0029c454  /data/app/com.sample.app-1/lib/arm/libpjsua2.so (bqPlayerCallback+420)
05-04 10:32:10.544 I/DEBUG   (  281):     #14 pc 00008daf  /system/lib/libwilhelm.so
05-04 10:32:10.544 I/DEBUG   (  281):     #15 pc 000559fd  /system/lib/libmedia.so (android::AudioTrack::processAudioBuffer()+1156)
05-04 10:32:10.544 I/DEBUG   (  281):     #16 pc 00055c69  /system/lib/libmedia.so (android::AudioTrack::AudioTrackThread::threadLoop()+168)
05-04 10:32:10.544 I/DEBUG   (  281):     #17 pc 0000ef55  /system/lib/libutils.so (android::Thread::_threadLoop(void*)+112)
05-04 10:32:10.544 I/DEBUG   (  281):     #18 pc 0000eac5  /system/lib/libutils.so
05-04 10:32:10.544 I/DEBUG   (  281):     #19 pc 000137b3  /system/lib/libc.so (__pthread_start(void*)+30)
05-04 10:32:10.544 I/DEBUG   (  281):     #20 pc 00011893  /system/lib/libc.so (__start_thread+6)

I suspected that it's trying to write logs from the wrong thread, but I have no clue on how to fix it. Disabling LogWriter the app does not throw this error.

Any help appreciated.

回答1:

I had the same issue. I don't know is it actual now, but I solved, as adviced in Official Doc. Where notice it is Garbage Collection problems:

class MyApp {
    private MyLogWriter logWriter;

    public void init()
    {
        /* Maintain reference to log writer to avoid premature cleanup by GC */
        logWriter = new MyLogWriter();
        epConfig.getLogConfig.setWriter(logWriter);
    }
}

回答2:

As GensaGames said, you need to maintain a reference otherwise it's going to crash when the GC will decide to cleanup objects. If you use a dependency injector (eg: dagger 2), you can add you custom logwriter class to your graph dependency and set the scope to Singleton or your Application scope.

来源：https://stackoverflow.com/questions/37022757/enabling-log-in-pjsip-for-android-forces-close-the-app