Let's say I binded to a service, and got an object reference to it through the IBinder object. I store the reference in my Activity object as a field. Then I unbind the service causing its destruction. What does the Service reference in the Activity refers to after the Service's destruction?
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you get a dead object – pskink Apr 27 '15 at 08:25
1 Answers
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Nothing. It's a classic out of bound state and if you access it the behaviour is unpredictable but it is never good.
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update
Please look at this example (taken from here):
public class BindingActivity extends Activity {
LocalService mService;
boolean mBound = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
@Override
protected void onStart() {
super.onStart();
// Bind to LocalService
Intent intent = new Intent(this, LocalService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
// Unbind from the service
if (mBound) {
unbindService(mConnection);
mBound = false;
}
}
/** Called when a button is clicked (the button in the layout file attaches to
* this method with the android:onClick attribute) */
public void onButtonClick(View v) {
if (mBound) {
// Call a method from the LocalService.
// However, if this call were something that might hang, then this request should
// occur in a separate thread to avoid slowing down the activity performance.
int num = mService.getRandomNumber();
Toast.makeText(this, "number: " + num, Toast.LENGTH_SHORT).show();
}
}
/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
LocalBinder binder = (LocalBinder) service;
mService = binder.getService();
mBound = true;
}
@Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
}
Please note the ServiceConnection.

Royi Benyossef
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Not really, you should never save an instance to IBinder anyway and you could simply use a boolean flag to represent whether you're bound or not. – Royi Benyossef Apr 27 '15 at 13:07
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Shouldn't save an instance? So how do I later communicate with the service I bound to? – f.khantsis Apr 27 '15 at 13:11
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OK i think i understand your question better now, updating my answer - please look. – Royi Benyossef Apr 27 '15 at 13:29
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Ok, thanks. Listen, this is a bit off topic, but I am just now starting Android development and it's very confusing, even though I am a decent Java programmer. Can you recommend me a really good tutorial/sample program to pay with/anything to ease the learning curve? – f.khantsis Apr 27 '15 at 15:23