Android 7.0 and 7.1 getApplication() ClassCastException

Question

In Developer Console I see a lot of crashes with stacktrace like this

java.lang.RuntimeException: 
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2984)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3045)
  at android.app.ActivityThread.-wrap14(ActivityThread.java:0)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1642)
  at android.os.Handler.dispatchMessage(Handler.java:102)
  at android.os.Looper.loop(Looper.java:154)
  at android.app.ActivityThread.main(ActivityThread.java:6776)
  at java.lang.reflect.Method.invoke(Native Method:0)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)
Caused by: java.lang.ClassCastException: 
  at com.myapp.ui.BaseActivity.getApp(BaseActivity.java:193)
  at com.myapp.ui.BaseActivity.onCreate(BaseActivity.java:275)
  at com.myapp.ui.CastActivity.onCreate(CastActivity.java:39)
  at com.myapp.ui.MainActivity.onCreate(MainActivity.java:268)
  at android.app.Activity.performCreate(Activity.java:6955)
  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1126)
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2927)

getApp method of BaseActivity is

public App getApp() {
        return (App) getApplication();
    }

App class is

public class App extends MultiDexApplication { ...

and in manifest application tag contains reference to this class

 <application
        android:name="com.myapp.App"

98% of crashes is for android 7.0, rest is 7.1. No other android versions are affected.

EDIT: I use proguard so it can be somehow related but keeping class

-keep class com.myapp.** { *;}
-keep interface com.myapp.** { *;}

Note: It may not be related but in same android versions it looks like App's onCreate method is sometimes not called. I observed it because some objects which are created in onCreate were null when they were accessed from Service (started by AlarmManager) or BroadcastReceiver

Does anyone has idea what can cause it, how to fix it or work around it? Thanks

EDIT 2: I ended up with something like this:

   public App getApp() {

    Application application = getApplication();
    App app = null;

    try {
        app = (App) application;
    } catch (Exception e) {
        if (application != null) {
            Log.e(TAG, "getApp Exception: application class: " + application.getClass().getName());
        } else {
            Log.e(TAG, "getApp Exception: application object is null");
        }
    }

    return app;
}

It at least doesn't crash and I can check getApp() == null

Greenlee

Hi, have you find the solution? – Allheal

@user5599807 unfortunately not – Greenlee

how common is this crash? there are always weird rare crashes that are vendor/rom specific. – Census

I see the problem on Android 8.0 and 8.1 as well. – Undergo

Answer 1

Casting fails because getApplication() returns an Application and NOT the desired sub-class.

I've had some success where I caught the error and asked the user to reboot their device or reinstall the app.

Unfortunately, there's no real fix to this rare crash. Google won't fix the lifecycle-related issue, but said it reduced in Android 7.1+. Source: https://issuetracker.google.com/issues/37137009

Foghorn

This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review – Lindsay

I think my newly edited answer provides closure to the OP's question. – Foghorn

Agreed. +1 from me. – Lindsay

Answer 2

I think you should cast getApplicationContext() into App instead.

Sphere

Can you explain why it should help please? – Greenlee

It is an alternative, sometimes when programming for android I experienced that minor changes like that can get rid of an exception. – Sphere

problem is that it may not return application object in some cases (ie vendor implementation of android) #5019045 – Greenlee

Answer 3

While I cannot say if this solution works.

I think that static Application instance should solve the problem.

class MyApp extends Application {
  private static final sInstance;

  public void onCreate() {
    sInstance = this;
  }

  public static MyApp getInstance() {
    return sInstance;
  }
}

Instead of calling getActivity() if you call MyApp.getInstance() you should not need to cast. So there should not be any ClassCastException anymore.

Discommodity

Answer 4

You should override attachBaseContext in your application class like this:

@Override
protected void attachBaseContext(Context base) {
    super.attachBaseContext(base);
    MultiDex.install(this);
}

Check this link for more information: https://developer.android.com/reference/android/support/multidex/MultiDexApplication.html

Anthropocentric

I don't have to do it because it's already done in MultiDexApplication. In link which you share it says you can extend MultiDexApplication or override attachBaseContext – Greenlee

@vandzi can you post your app class oncreate – Anthropocentric

There is nothing useful there just super.onCreate(); Analytics initialisation. I think problem is somewhere else – Greenlee

I recreated your implementation and it works on my side on android 7.0, it think it is somewhere else – Anthropocentric

It doesn't always crash. It crashes only for some devices/users and probably randomly. – Greenlee

Does it crash on samsungs? – Sphere

Yes, I saw samsung s7 as top device in reports, but other devices too. Common thing is android 7.0 – Greenlee

Answer 5

This might help

public class App extends MultiDexApplication { 

        public static App app = null;

        public static App getInstance() {
            return app;
        }

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

you doesn't need to cast getApplication(), reason is you are already in Application class so simply just use this keyword to get application instance. Hope you find useful

Sashasashay

getApp is in activity so I have to cast it – Greenlee

Though you doesn't need to cast use getApplicationContext() in your activity – Sashasashay

developer.android.com/reference/android/content/Context.html getApplicationContext() Return the context of the single, global Application object of the current process. – Sashasashay

I don't want to get context. I want to get App instance. – Greenlee

that I already answered. you need to read above statement. global Application object (That means App instance) – Sashasashay