Add convenience CompoundDisposable to BaseActivity.

...to be used by subclasses, and gets disposed automatically.

Author: dbrant

app/src/main/java/fr/free/nrw/commons/auth/AuthenticatedActivity.java

@@ -58,13 +58,12 @@ protected void onSaveInstanceState(Bundle outState) {
      * Makes API call to check if user is blocked from Commons. If the user is blocked, a snackbar
      * is created to notify the user
      */
-    protected void showBlockStatus()
-    {
-        Observable.fromCallable(() -> mediaWikiApi.isUserBlockedFromCommons())
+    protected void showBlockStatus() {
+        compositeDisposable.add(Observable.fromCallable(() -> mediaWikiApi.isUserBlockedFromCommons())
                 .subscribeOn(Schedulers.io())
                 .observeOn(AndroidSchedulers.mainThread())
                 .filter(result -> result)
                 .subscribe(result -> ViewUtil.showShortSnackbar(findViewById(android.R.id.content), R.string.block_notification)
-                );
+                ));
     }
 }

app/src/main/java/fr/free/nrw/commons/theme/BaseActivity.java

@@ -8,13 +8,14 @@
 import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.di.CommonsDaggerAppCompatActivity;
 import fr.free.nrw.commons.kvstore.JsonKvStore;
-import fr.free.nrw.commons.kvstore.JsonKvStore;
+import io.reactivex.disposables.CompositeDisposable;
 
 public abstract class BaseActivity extends CommonsDaggerAppCompatActivity {
     @Inject
     @Named("default_preferences")
     public JsonKvStore defaultKvStore;
 
+    protected CompositeDisposable compositeDisposable = new CompositeDisposable();
     protected boolean wasPreviouslyDarkTheme;
 
     @Override
@@ -33,4 +34,10 @@ protected void onResume() {
 
         super.onResume();
     }
+
+    @Override
+    protected void onDestroy() {
+        super.onDestroy();
+        compositeDisposable.clear();
+    }
 }