Crashing in Crashing in StyleStyle

About /me• Tam HANNA

– CEO, Tamoggemon Ltd.

– Director, Tamoggemon Holding k.s.

– Runs web sites about mobile computing

– Writes scientific books

About /girly• Annette BOSBACH

– Clerk to the coordinating office, Tamoggemon Holding k.s.

– First GottaTxt fan

Overview• The schedule

• Why track crashes

• Basic methods

• ACRA

Source code• JAVA Source code is available

– Via Twitter

• Our IP: free to use– Too low to qualify for protection

– Plus, you have to listen to us so

The schedule

Crash first, Qt second

• 60% / 40%– More about Qt: at our booth

• Please tweet about us

The @tamhanna show is cool

GottaTxt is the best app at #droidconnl

After listening to @tamhanna, my app doesn‘t

crash anymore!!!

@tamhanna threw chocolate on my head. Ouch! #droidconnl

Why track Why track crashes?crashes?

Market is crowded• Bad ratings kill an application

• BUT: responding to feedback helps– „The developer responds to ME!!!“

– I am important

– Ego issues => superhappy customer

Why track crashes?• Isn‘t it better not to crash?

– Matthew A Brenner, UnME2

• Yes, but– Ever-increasing number of LOC– Fragmentation (to see /me mention that )– Margin pressure

• TU144 / Concorde problem

Users are stupid• What OS version do you use?

– Common question for developers

– Perceived as denigration by some users

• Send me a file from the file system!– Common question for developers

– But for developer‘s wife or husband?

Crash vs stat tracking

• Stat tracking– Which flows are used

– Entry/Exit path analysis

– e.g. Google Analytics

• Crash tracking– What causes crashes

– Where do users „die“

And there‘s more• Track „points of pain“ for users

– Rejection of user input

– Games: user death

• Fix them in the next release– First 2min with application are critical

Private debuggerPrivate debugger

Picture: Wikimedia Commons / fluteflute

What‘s that• Special mode of operation

– Allows developer access to internals– ON the users phone

• Can be accessed via secret key– Must be easy to enter, difficult to guess– Prevent users from entering it by mistake

• Customer provides info to developer

How to implement• By foot

• No ready made libraries available

Example• GottaTxt

1. Open Thread

2. Enter „Secret Code“

3. Enter commands

4. Give response

Try it at our booth

FREE VODKA FREE VODKA INCLUDED!!!INCLUDED!!!

Basic crash Basic crash handlinghandling

Wikimedia Commons / David Monack

Really easy way• Thread.setDefaultExceptionHandler()

• Write to file, then die

• Tell user to email file– Can usually be accomplished

Problems• IO is buffered

• Thread terminates before data written

• Data lost

• !!!Occurs rarely!!!– Never saw it on Android

Non-working solution

• StackOverflow user gupta

• Fire intent from exception handler

• Hope for it to arrive

Non-working solution - II

• Doesn‘t work in practice

• Intent never arrives at application

Workable solution• Completely override crash handling

– No Android Crash message shown

• Re-invoke application

• Example a360crash1

public ExceptionTrap(Context _context, String _filePath)

{

myContext=_context;

myFilePath=_filePath;

myHandler=Thread.getDefaultUncaughtExceptionHandler();

}

@Overridepublic void uncaughtException(Thread _t, Throwable _a) {

try{StringWriter s=new StringWriter();_a.printStackTrace(new PrintWriter(s));

Intent launchIntent=new Intent(ErrorReporter.INTENTSTRING);launchIntent.putExtra("StackTrace", s.toString());launchIntent.putExtra("FilePath", myFilePath);

PendingIntent pIntent=PendingIntent.getService(myContext, 0, launchIntent, launchIntent.getFlags());AlarmManager mgr = (AlarmManager) myContext.getSystemService(Context.ALARM_SERVICE);mgr.set(AlarmManager.RTC, System.currentTimeMillis() + 2000, pIntent);

System.exit(2);

public class ErrorReporter extends IntentService {

public static final String INTENTSTRING ="com.tamoggemon.a360crash1.intent.CALLERRORREPORTER";

public ErrorReporter() {super("TAG");}

@Override public void onCreate() { super.onCreate(); }

protected void onHandleIntent(Intent intent) {//Newline, etc removed

try{boolean newFile=false;File writeFile=new File(intent.getStringExtra("FilePath"));if(writeFile.exists()==false){newFile=true;writeFile.createNewFile();} BufferedWriter buf = new BufferedWriter(new FileWriter(writeFile, true)); if(newFile) { buf.append(android.os.Build.MODEL); buf.append(android.os.Build.VERSION.RELEASE); } buf.append("-------------------CRASH-------------------") buf.append(intent.getStringExtra("StackTrace"));

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); myTrap=new ExceptionTrap(this, "/sdcard/A360Crash.log"); Thread.setDefaultUncaughtExceptionHandler(myTrap); setContentView(R.layout.main); findViewById(R.id.button1).setOnClickListener(this); }

@Overridepublic void onClick(View v) {

throw new RuntimeException("Fehler erfolgreich ausgelöst!");}

<service android:name=".ErrorReporter">

<intent-filter >

<action android:name="com.tamoggemon.a360crash1.intent.CALLERRORREPORTER" />

</intent-filter>

</service>

ACRAACRAWikimedia Commons / gerol

What is ACRA• Android Crash Report for Android

• Very flexible library

• Can dump crash data to Google Docs

Set up online• Google Account needed

• Create new form via SpreadSheet

• Export it to get FormKey

Integrate into app@ReportsCrashes(formKey =

"dExKcElJWjVaUkpMem9WOWg3VE80SlE6MQ") public class MyApplication extends Application { @Override public void onCreate() { ACRA.init(this); super.onCreate(); }}

Custom data• if(v==cmdStoreA)• {•

ErrorReporter.getInstance().putCustomData("myVariable", "A");

• }• if(v==cmdStoreB)• {•

ErrorReporter.getInstance().putCustomData("myVariable", "B");

• }

Enable / Disable• if(v==cmdEnable)• {• SharedPreferences

aPrefs=ACRA.getACRASharedPreferences();• Editor anEditor=aPrefs.edit();• anEditor.putBoolean("acra.enable", true);• anEditor.commit();• }• if(v==cmdDisable)• {• SharedPreferences

aPrefs=ACRA.getACRASharedPreferences();• Editor anEditor=aPrefs.edit();• anEditor.putBoolean("acra.enable", false);• anEditor.commit();• }

Further Options• ACRA does a LOT

– Interact with users

– Custom databases

• https://github.com/ACRA/acra/wiki/AdvancedUsage

OOP FTW

Problem of all solutions

• Integration requires manual work– Find all classes

– Integrate logging code

• Better solution: „stub objects“

How to implement it• By foot

• Loads of leeway for developers– Abstract actual logging?

Examplepublic abstract class TMGNActivity extends Activity {

@Override public final void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState); logThis("Creating Activity"); logThis(getClass().getName()); tmgnOnCreate(savedInstanceState);

} public abstract void tmgnOnCreate(Bundle savedInstanceState);

Other vendors

Google Play Crash tracking

• Google Play provides crash tracking– Rudimentary, can‘t add own data

• Better than nothing– Check often

– Log-in freq. could (!!!) be used for ranking

Crash Trackers• BugSense

– Specialized service

• Flurry– Afterthought for premium analytics

• Yours?– Tell us in Q&A

ConclusionsConclusions

Crashes will happen• Today‘s mobile apps are

– Highly complex

– Underfunded (thanks, Apple!)

• Even the OS crashes sometimes

• Users tolerate reasonable crashingUsers tolerate reasonable crashing

Work-arounds are needed

• Paid users expect frequent updates– Let them generate their wishes themselves

• Monitoring is first step to improvement– See what users really think

Olympic spirit• Important:

– TRACK CRASHES

– Perform PDCA cycle on data

• Not so important– How to track them

– Track 100% of them

?!?

tamhan@tamoggemon.com

@tamhanna