Fix the mess up with OnBackPress support on Fragment

vector/src/main/java/im/vector/riotx/core/platform/VectorBaseActivity.kt

@@ -265,18 +265,21 @@ abstract class VectorBaseActivity : BaseMvRxActivity(), HasScreenInjector {
         return super.onOptionsItemSelected(item)
     }
 
-    protected fun recursivelyDispatchOnBackPressed(fm: FragmentManager): Boolean {
-        // if (fm.backStackEntryCount == 0)
-        //     return false
+    override fun onBackPressed() {
+        val handled = recursivelyDispatchOnBackPressed(supportFragmentManager)
+        if (!handled) {
+            super.onBackPressed()
+        }
+    }
 
-        val reverseOrder = fm.fragments.filter { it is OnBackPressed }.reversed()
+    private fun recursivelyDispatchOnBackPressed(fm: FragmentManager): Boolean {
+        val reverseOrder = fm.fragments.filter { it is VectorBaseFragment }.reversed()
         for (f in reverseOrder) {
             val handledByChildFragments = recursivelyDispatchOnBackPressed(f.childFragmentManager)
             if (handledByChildFragments) {
                 return true
             }
-            val backPressable = f as OnBackPressed
-            if (backPressable.onBackPressed()) {
+            if (f is OnBackPressed && f.onBackPressed()) {
                 return true
             }
         }

vector/src/main/java/im/vector/riotx/core/platform/VectorBaseFragment.kt

@@ -19,11 +19,7 @@ package im.vector.riotx.core.platform
 import android.content.Context
 import android.os.Bundle
 import android.os.Parcelable
-import android.view.LayoutInflater
-import android.view.Menu
-import android.view.MenuInflater
-import android.view.View
-import android.view.ViewGroup
+import android.view.*
 import androidx.annotation.CallSuper
 import androidx.annotation.LayoutRes
 import androidx.annotation.MainThread
@@ -42,7 +38,7 @@ import io.reactivex.disposables.CompositeDisposable
 import io.reactivex.disposables.Disposable
 import timber.log.Timber
 
-abstract class VectorBaseFragment : BaseMvRxFragment(), OnBackPressed, HasScreenInjector {
+abstract class VectorBaseFragment : BaseMvRxFragment(), HasScreenInjector {
 
     // Butterknife unbinder
     private var mUnBinder: Unbinder? = null
@@ -132,10 +128,6 @@ abstract class VectorBaseFragment : BaseMvRxFragment(), OnBackPressed, HasScreen
         super.onViewStateRestored(savedInstanceState)
     }
 
-    override fun onBackPressed(): Boolean {
-        return false
-    }
-
     override fun invalidate() {
         //no-ops by default
         Timber.w("invalidate() method has not been implemented")

vector/src/main/java/im/vector/riotx/features/home/HomeActivity.kt

@@ -202,10 +202,7 @@ class HomeActivity : VectorBaseActivity(), ToolbarConfigurable {
         if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
             drawerLayout.closeDrawer(GravityCompat.START)
         } else {
-            val handled = recursivelyDispatchOnBackPressed(supportFragmentManager)
-            if (!handled) {
-                super.onBackPressed()
-            }
+            super.onBackPressed()
         }
     }
 

vector/src/main/java/im/vector/riotx/features/home/room/list/RoomListFragment.kt

@@ -250,7 +250,7 @@ class RoomListFragment : VectorBaseFragment(), RoomSummaryController.Listener, O
             return true
         }
 
-        return super.onBackPressed()
+        return false
     }
 
     // RoomSummaryController.Callback **************************************************************

vector/src/main/java/im/vector/riotx/features/login/LoginActivity.kt

@@ -79,7 +79,6 @@ class LoginActivity : VectorBaseActivity() {
         showDisclaimerDialog(this)
     }
 
-
     companion object {
         fun newIntent(context: Context): Intent {
             return Intent(context, LoginActivity::class.java)

vector/src/main/java/im/vector/riotx/features/login/LoginSsoFallbackFragment.kt

@@ -33,6 +33,7 @@ import im.vector.matrix.android.api.auth.data.Credentials
 import im.vector.matrix.android.internal.di.MoshiProvider
 import im.vector.riotx.R
 import im.vector.riotx.core.di.ScreenComponent
+import im.vector.riotx.core.platform.OnBackPressed
 import im.vector.riotx.core.platform.VectorBaseFragment
 import kotlinx.android.synthetic.main.fragment_login_sso_fallback.*
 import timber.log.Timber
@@ -42,7 +43,7 @@ import java.net.URLDecoder
 /**
  * Only login is supported for the moment
  */
-class LoginSsoFallbackFragment : VectorBaseFragment() {
+class LoginSsoFallbackFragment : VectorBaseFragment(), OnBackPressed {
 
     private val viewModel: LoginViewModel by activityViewModel()