misc: add missing null checks

Change-Id: Ie99c118b1a9584aa8f65b54c022b36e68468b954

ring-android/app/src/main/java/cx/ring/client/HomeActivity.kt

@@ -160,7 +160,7 @@ class HomeActivity : AppCompatActivity(), Colorable, ContactPickerFragment.OnCon
         }
         WindowCompat.setDecorFitsSystemWindows(window, false)
 
-        mHomeFragment = supportFragmentManager.findFragmentById(R.id.home_fragment) as HomeFragment
+        mHomeFragment = supportFragmentManager.findFragmentById(R.id.home_fragment) as? HomeFragment?
         frameContent = supportFragmentManager.findFragmentById(fragmentContainerId)
         supportFragmentManager.addOnBackStackChangedListener {
             frameContent = supportFragmentManager.findFragmentById(fragmentContainerId)
@@ -169,7 +169,7 @@ class HomeActivity : AppCompatActivity(), Colorable, ContactPickerFragment.OnCon
             mBinding!!.frame.isVisible = true
         }
 
-        fConversation = supportFragmentManager.findFragmentByTag(ConversationFragment::class.java.simpleName) as ConversationFragment?
+        fConversation = supportFragmentManager.findFragmentByTag(ConversationFragment::class.java.simpleName) as? ConversationFragment?
         if (fConversation != null) {
             Log.w(TAG, "Restore conversation fragment $fConversation")
             conversationBackPressedCallback.isEnabled = true
@@ -180,7 +180,6 @@ class HomeActivity : AppCompatActivity(), Colorable, ContactPickerFragment.OnCon
         }
         onBackPressedDispatcher.addCallback(this, conversationBackPressedCallback)
         handleIntent(intent)
-
     }
 
     override fun onDestroy() {

ring-android/app/src/main/java/cx/ring/fragments/ConversationFragment.kt

@@ -777,22 +777,24 @@ class ConversationFragment : BaseSupportFragment<ConversationPresenter, Conversa
         val searchMenuItem = menu.findItem(R.id.conv_search)
         searchMenuItem.setOnActionExpandListener(object : MenuItem.OnActionExpandListener {
             override fun onMenuItemActionCollapse(item: MenuItem): Boolean {
+                val binding = binding ?: return false
                 presenter.stopSearch()
-                binding!!.histList.adapter = mAdapter
+                binding.histList.adapter = mAdapter
                 updateListPadding()
                 currentBottomView?.isVisible = true
                 if (animation.isStarted) animation.cancel()
-                animation.setIntValues(binding!!.histList.paddingBottom, currentBottomView!!.height + marginPxTotal)
+                animation.setIntValues(binding.histList.paddingBottom, currentBottomView!!.height + marginPxTotal)
                 animation.start()
                 return true
             }
             override fun onMenuItemActionExpand(item: MenuItem): Boolean {
+                val binding = binding ?: return false
                 mSearchAdapter = ConversationAdapter(this@ConversationFragment, presenter)
                 presenter.startSearch()
                 currentBottomView?.isVisible = false
-                binding!!.histList.adapter = mSearchAdapter
+                binding.histList.adapter = mSearchAdapter
                 if (animation.isStarted) animation.cancel()
-                animation.setIntValues(binding!!.histList.paddingBottom, marginPxTotal)
+                animation.setIntValues(binding.histList.paddingBottom, marginPxTotal)
                 animation.start()
                 return true
             }