fixes for the java tutorial

Author: tschellenbach

samplejava/src/main/java/com/example/chattutorialjava/ChannelActivity3.java

@@ -57,7 +57,6 @@ protected void onCreate(@Nullable Bundle savedInstanceState) {
         MessageListView messageListView = findViewById(R.id.messageListView);
         ChannelHeaderView channelHeaderView = findViewById(R.id.channelHeaderView);
         MessageInputView messageInputView = findViewById(R.id.messageInputView);
-        TextView typingHeader = findViewById(R.id.typingHeader);
 
         // Step 1 - Create 3 separate ViewModels for the views so it's easy to customize one of the components
         ChannelViewModelFactory factory = new ChannelViewModelFactory(cid);
@@ -109,8 +108,9 @@ public void handleOnBackPressed() {
         });
 
         // Custom typing info header bar
+        TextView typingHeaderView = findViewById(R.id.typingHeaderView);
         String nobodyTyping = "nobody is typing";
-        typingHeader.setText(nobodyTyping);
+        typingHeaderView.setText(nobodyTyping);
 
         // Obtain a ChannelController
         ChatDomain.instance().getUseCases().getGetChannelController().invoke(cid).enqueue((result) -> {
@@ -120,14 +120,14 @@ public void handleOnBackPressed() {
                 // Observe typing users
                 channelController.getTyping().observe(this, users -> {
                     if (users.isEmpty()) {
-                        typingHeader.setText(nobodyTyping);
+                        typingHeaderView.setText(nobodyTyping);
                     } else {
                         List<String> userNames = new LinkedList<>();
                         for (User user : users) {
                             userNames.add((String)user.getExtraData().get("name"));
                         }
                         String typing = "typing: " + TextUtils.join(", ", userNames);
-                        typingHeader.setText(typing);
+                        typingHeaderView.setText(typing);
                     }
                 });
             });

samplejava/src/main/java/com/example/chattutorialjava/ChannelActivity4.java

@@ -58,7 +58,6 @@ protected void onCreate(@Nullable Bundle savedInstanceState) {
         MessageListView messageListView = findViewById(R.id.messageListView);
         ChannelHeaderView channelHeaderView = findViewById(R.id.channelHeaderView);
         MessageInputView messageInputView = findViewById(R.id.messageInputView);
-        TextView typingHeader = findViewById(R.id.typingHeader);
 
         // Step 1 - Create 3 separate ViewModels for the views so it's easy to customize one of the components
         ChannelViewModelFactory factory = new ChannelViewModelFactory(cid);
@@ -110,8 +109,9 @@ public void handleOnBackPressed() {
         });
 
         // Custom typing info header bar
+        TextView typingHeaderView = findViewById(R.id.typingHeaderView);
         String nobodyTyping = "nobody is typing";
-        typingHeader.setText(nobodyTyping);
+        typingHeaderView.setText(nobodyTyping);
 
         Set<String> currentlyTyping = new HashSet<>();
         ChatClient
@@ -134,7 +134,7 @@ public void handleOnBackPressed() {
                             if (!currentlyTyping.isEmpty()) {
                                 typing = "typing: " + TextUtils.join(", ", currentlyTyping);
                             }
-                            typingHeader.setText(typing);
+                            typingHeaderView.setText(typing);
                             return Unit.INSTANCE;
                         });
     }

samplejava/src/main/res/layout/activity_channel_3.xml

@@ -13,7 +13,7 @@
         app:layout_constraintTop_toTopOf="parent" />
 
     <TextView
-        android:id="@+id/typingHeader"
+        android:id="@+id/typingHeaderView"
         android:layout_width="match_parent"
         android:layout_height="31dp"
         android:background="#CCCCCC"
@@ -29,7 +29,7 @@
         app:layout_constraintBottom_toTopOf="@+id/messageInputView"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/typingHeader"
+        app:layout_constraintTop_toBottomOf="@+id/typingHeaderView"
         android:clipToPadding="false"
         android:paddingBottom="16dp"
         android:background="#f3f5f8"

samplejava/src/main/res/layout/activity_channel_4.xml

@@ -13,7 +13,7 @@
         app:layout_constraintTop_toTopOf="parent" />
 
     <TextView
-        android:id="@+id/typingHeader"
+        android:id="@+id/typingHeaderView"
         android:layout_width="match_parent"
         android:layout_height="31dp"
         android:background="#CCCCCC"
@@ -29,7 +29,7 @@
         app:layout_constraintBottom_toTopOf="@+id/messageInputView"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/typingHeader"
+        app:layout_constraintTop_toBottomOf="@+id/typingHeaderView"
         android:clipToPadding="false"
         android:paddingBottom="16dp"
         android:background="#f3f5f8"