Cannot cast Application to CustomApplication

Question

I have a CustomApplication extends Application class, which is registered in AndroidManifest

 <application
    ....
// Please, pay attention that I got this in my Manifest
    android:name=".CustomApplication">

And at different part of my application, both some activities and services I do getApplication()/getApplicationContext() then cast it to CustomApplication and it crashes in production on a variety of devices/sdk versions(beginning at android 6) due to a class cast exception. Caused by: java.lang.ClassCastException

Example:

class CustomApplication extends Application{
...
public static CustomApplication with(Context context) {
       return (CustomApplication) context.getApplicationContext(); //crashes here
   }
}

and service example:

class CustomService extends IntentService{
...
@Override
rotected void onHandleIntent(@Nullable Intent intent) {
        CustomApplication app = CustomApplication.from(getApplication());
        // tried getApplicationContext() also
}
}

and activity example:

class CustomActivity extends AppCompatActivity{
...
@Override
protected void onCreate(...){
   CustomApplication app = CustomApplication.with(this);
}

What I've tried:

Tried services with different process=":process"
Tried deep linking with different launchModes
Tried activities with taskAffinity
launching from push notifications
process cleaning with system tray(on device), ps kill int adb shell

nothing helps me to reproduce an issue on emulator

I don't use Instant Run also (never used it)

Please don't provide me with suggests of using static application context instance

@cricket_007 if I would be able to reproduce it, I wouldn't ask question here — Alex, Oct 16 '17 at 13:21
Why are you casting your context? `getApplication ()` and `getApplicationContext()` are not the same. getApplicationContext returns the context of the single, global Application object. — codeFreak, Oct 16 '17 at 13:23
@cricket_007 got 1kk monthly active users on project. That issue happens like ~100 times a day — Alex, Oct 16 '17 at 13:23
@codeFreak https://stackoverflow.com/questions/5018545/getapplication-vs-getapplicationcontext — Alex, Oct 16 '17 at 13:24
Is there a specific case why a regular singleton class can't be used? — OneCricketeer, Oct 16 '17 at 13:25
@cricket_007 I got DI(Dagger 2) and I got legacy part of an application that can't be used with dagger 2 for now. Anyway, even If I would rewrite everything for a `valid` singletons - I'm still curious about that stuff — Alex, Oct 16 '17 at 13:27
@cricket_007 Cause it crashes in both services and activity. — Alex, Oct 16 '17 at 13:28
what is that `with()` method supposed to do? It seems useless — Tim, Oct 16 '17 at 13:39
@TimCastelijns it's been done for convenience. You pass your current context there and you get an application instance. You can find out that kind of stuff in Telegram/Actor source codes — Alex, Oct 16 '17 at 13:41
Read https://stackoverflow.com/questions/5018545/getapplication-vs-getapplicationcontext?noredirect=1&lq=1 — nomag, Oct 16 '17 at 13:41
Why does `with()` not just return `this`? without requiring a context as parameter — Tim, Oct 16 '17 at 13:42
@TimCastelijns because I don't hold a static reference of Application context — Alex, Oct 16 '17 at 13:44
@TimCastelijns I cannot return `this` instance from a static method — Alex, Oct 16 '17 at 13:47
@Alex Please read given link for explanation why it can not be cast sometimes: https://stackoverflow.com/a/6760019/8101621 — nomag, Oct 16 '17 at 17:10

score 0 · Answer 1 · answered Oct 16 '17 at 13:34

0

You can keep a static reference of your CustomApplication like below. You don't need to cast in the following way.

public class CustomApplication extends Application {
    private static CustomApplication instance;

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

        instance = this;
    }

    public static CustomApplication getContext() {
        return instance;
    }
}

Then call CustomApplication.getContext();

answered Oct 16 '17 at 13:34

ARiF

1,079
10
23

I'm here to find out why .applicationContext cannot be casted to CustomApplication class. Cause it's going to clarify me a lot of android internal processes – Alex Oct 16 '17 at 13:46

Ricardo · Answer 2 · 2017-10-16T14:47:11.977

0

You need to define your custom application in the manifest as follow:

<application
    ....
    android:name="my.package.path.CustomApplication"> 

    ... activities ....

 </application>

Also, you are getting an instance of a class that extends Application, not Context, that being said you should call this the following way:

CustomApplication customApplication;
customApplication = (CustomApplication)getApplication();

What you might have to apply in case you have BroadcastReceiver(No context available) is:

customApplication = (CustomApplication)getApplicationContext().getApplication();

edited Oct 16 '17 at 14:47

answered Oct 16 '17 at 14:00

Ricardo

9,136
3
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35

I'm just giving you a full example in how you should use it. Try out what I've posted and you will see it will work. – Ricardo Oct 16 '17 at 14:09
it's been there for like 4 years already. App in production has 1 million monthly active users – Alex Oct 16 '17 at 14:12
and why should I do getapplicationContext().getApplication() for intent service? – Alex Oct 16 '17 at 14:13
Intent service extends service, therefor you don't have a context. When you do `(CustomApplication)getApplication` in an Activity you are basically writing `(CustomApplication)this.getApplication`. Thats why in classes that are not Activities you need to either pass the context, or get the application context, which is the case of an IntentService – Ricardo Oct 16 '17 at 14:16
I will, I gotta do a staged rollout on the audience. I'm not capable to reproduce it on any of my devices at any scenario – Alex Oct 16 '17 at 14:18
And as I mentioned in my question, I tried both `.getApplicationContext()` and `.getApplication()` from service. And they all failed – Alex Oct 16 '17 at 14:21
I just crashes ~50-100 times a day. So there's a specific scenario during which .getApplication/getApplicationContext does not return a CustomApplication instance. I suppose it to be a vendor specific issue – Alex Oct 16 '17 at 14:22
It is a possibility. I've worked with a few applications already with thousands of monthly users and never had a problem with the approach I gave you – Ricardo Oct 16 '17 at 14:26
But you gave me the same approach I use – Alex Oct 16 '17 at 14:32
I have my application class registered in manifest, and I do the same class casting of .getApplication as you do. What's the difference? – Alex Oct 16 '17 at 14:33
the only difference I've found out is you do .getApplicationContext().getApplication() and I asked you to provide me with some links to resources to clarify that for me – Alex Oct 16 '17 at 14:33
I explained when and why you must call getApplicationContext in a comment above. read it – Ricardo Oct 16 '17 at 14:38
But intent Service has context. It is a context. You can examine it both in android SDK and android documentation; And it has both .getApplication() and .getApplicationContext() methods – Alex Oct 16 '17 at 14:42
You are correct. I was confusing with BroadcastReceiver, thats where you need to call getApplicationContext. – Ricardo Oct 16 '17 at 14:46

Cannot cast Application to CustomApplication

2 Answers2