Develop Reference

How do I handle uncaught exceptions and then delegate handling back to the system?

I want to send a firebase crash report for every uncaught exception in my app but I also want to Android system to show the "App has stopped responding" dialog. How do I go about this?? I already have an UncaughtException handler that sends the firebase crash report. My issue now is letting Android handle the rest of the process.

The uncaught exception can be delegated back to system by storing the old exception handler and passing uncaught exceptions to it.
First create an Application class as below:
public class Controller extends Application {
private static Thread.UncaughtExceptionHandler defaultHandler;
#Override
public void onCreate() {
super.onCreate();
if (defaultHandler == null) {
defaultHandler = Thread.getDefaultUncaughtExceptionHandler();
}
Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
#Override
public void uncaughtException(Thread t, Throwable e) {
FirebaseCrash.report(e); //or whatever
defaultHandler.uncaughtException(t, e); //this will show crash dialog.
}
});
}
}
Then use this class as application in the manifest as:
<application
android:name=".Controller"
... />

How to catch crash without disturbing the normal crash flow

I know there are already good tools available like crashlytics, but i have a requirment and i can't use these tools.
All i need to is to save the crash log before application exists, and that without disturbing the normal flow, and using any 3rd party library
I have implemented this, but it has disturb the normal flow of android crashing. I want to save the log, but don't want to disturb the normal crashing flow.
This is what i am doing to save the crash log.
public void registerCrash(){
Thread.setDefaultUncaughtExceptionHandler (new Thread.UncaughtExceptionHandler()
{
#Override
public void uncaughtException (Thread thread, Throwable e)
{
handleUncaughtException (thread, e);
}
});
}
public void handleUncaughtException (Thread thread, Throwable e)
{
thread.getStackTrace();
savePreferenceData(e.toString());
System.exit(0);
}
public void savePreferenceData(String data) {
SharedPreferences sharedPreferences= context.getSharedPreferences(LOG_DATA, Context.MODE_PRIVATE);
SharedPreferences.Editor prefsEditor = sharedPreferences.edit();
prefsEditor.putString(STACK_TRACE, data);
prefsEditor.apply();
}
The problem is that, It restarts the application, without giving the default Alert dialog to user. Unfortunately App has stopped.
Kindly guide me how to save crash log witout disturbing the normal crash mechanisim

Before setting the UncaughtExceptionHandler, keep track of the one that was set before and simply call it from your own handler after you are done:
private Thread.UncaughtExceptionHandler defaultExceptionHandler;
public void registerCrash(){
defaultExceptionHandler = Thread.getDefaultUncaughtExceptionHandler();
Thread.setDefaultUncaughtExceptionHandler (new Thread.UncaughtExceptionHandler(){
#Override
public void uncaughtException (Thread thread, Throwable e){
handleUncaughtException (thread, e);
if(defaultExceptionHandler != null){
defaultExceptionHandler.uncaughtException(thread, e);
}
}
});
}

Runtime error handling on android

I want to make some classes that catch runtime errors on android and offers the user the option to restore the last saved instance state of the app.
I was thinking of extending the Activity and Fragment classes and implement something that saves their state. In the meantime, another class handles every start of an activity or fragment, putting them in a stack.
I want to catch every possible exception in the app, hopefully making errors less bothersome for the user.
Any advice on how I should handle this?
How would this error checking influence the performance of an app?

It's not a good solution and i don't know if it's useful for you, but you can caught exceptions in Application Class.
public class MyApplication extends Application
{
public void onCreate ()
{
// Setup handler for uncaught exceptions.
Thread.setDefaultUncaughtExceptionHandler (new Thread.UncaughtExceptionHandler()
{
#Override
public void uncaughtException (Thread thread, Throwable e)
{
handleUncaughtException (thread, e);
}
});
}
public void handleUncaughtException (Thread thread, Throwable e)
{
e.printStackTrace();
// do what ever you want.
}
}

You can use try catch blocks to catch runtime errors. If you use try catch efficiently with throws your app won't crash in first place hence no need to maintain stack of activities. btw maintaining stacks of previous activity in neither memory efficient nor advisable.

android - callback function for handling crashes

I need to handle crashes in android application,Is there any callback function or overridden method in activity class which will be called when the app crashes?
Guide me in solving this...

You can set an uncaught exception handler which will be called every time. Like this
final Thread.UncaughtExceptionHandler defaultHandler = Thread.getDefaultUncaughtExceptionHandler();
Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
#Override
public void uncaughtException(Thread thread, Throwable throwable) {
// do your magic
defaultHandler.uncaughtException(thread, throwable);
}
});
You should probably subclass the Application class and run this code as the first thing in the OnCreate method. Getting the default handler and passing the exception along is to ensure proper handling after you are done performing magic.
What are you trying to achieve?

android: how to quit the app properly on error

I added an exceptionhandler for unhandled exceptions, to know that the app has crashed on the next app start:
#Override
public void uncaughtException(Thread thread, Throwable ex) {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
SharedPreferences.Editor editor = preferences.edit();
editor.putString("crashed", "yes");
editor.commit();
}
I added the handler via:
Thread.setDefaultUncaughtExceptionHandler(this);
Now the thing is: since I added the handler, the app behaves differently on error:
Before I added the handler I got a popup telling me that the app has crashed.
Now, after adding the handler the app just freezes, and after a while android shows me a popup telling me that the app does not respond anymore and whether I want to wait any longer. This is not good IMO. Any hints, how to properly exit after an application crash?

you can save the original exception handler , so that you can call it after you are done with doing your own custom operations on the unhandled exception . something like this:
//Inside UncaughtExceptionHandler.java:
…
private UncaughtExceptionHandler defaultUEH;
public DefaultExceptionHandler()
{
this.defaultUEH = Thread.getDefaultUncaughtExceptionHandler();
}
#Override
public void uncaughtException(Thread t, Throwable e)
{
//do anything you wish about the Throwable e :getStackTrace(),getCause(),getClass()...
//call the original uncaught exception handler:
defaultUEH.uncaughtException(t, e);
}

I suggest that you integrate your logic with ACRA, so that it can handle the issues of crash reporting and cleanup.