diff --git a/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModel.java b/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModel.java
index 76fef14..8022d53 100644
--- a/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModel.java
+++ b/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModel.java
@@ -58,10 +58,14 @@
         this.chatroomResource = retrofit.create(ChatroomResource.class);
     }
 
-    public ChatViewModel(String userId, String token, String chatroomId) {
+    public void setChatRoomId(String chatRoomId) {
+        this.chatroomId = chatRoomId;
+    }//追加しました。作られたときはchatroomIdが決まってないので、後からchatroomIdをセットできるようにしました。
+
+    public ChatViewModel(String userId, String token) {
         this.userId = userId;
         this.token = token;
-        this.chatroomId = chatroomId;
+        this.chatroomId = null;//nullにしました引数をなくしました。
 
 
         this.retrofit = new Retrofit.Builder()
@@ -83,7 +87,8 @@
                 }, 10_000); // 10秒後に通知
             }
             foundChatroom(userId,token);
-            loadLatestMessage(chatroomId, userId, token);
+            if (chatroomId != null) loadLatestMessage(chatroomId, userId, token);
+            //chatroomIdがnullの時は呼び出さないようにしました
         };
     }
 
diff --git a/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModelFactory.java b/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModelFactory.java
index 48d5ce0..d9d8ec4 100644
--- a/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModelFactory.java
+++ b/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModelFactory.java
@@ -9,20 +9,18 @@
 public class ChatViewModelFactory implements ViewModelProvider.Factory {
     private final String userId;
     private final String token;
-    private final String chatroomId;
 
-    public ChatViewModelFactory(String userId, String token, String chatroomId) {
+    public ChatViewModelFactory(String userId, String token) {
         this.userId = userId;
         this.token = token;
-        this.chatroomId = chatroomId;
-    }
+    }//chatroomIdを削除しました。
 
     @NonNull
     @Override
     public <T extends ViewModel > T create(@NonNull Class<T> modelClass) {
         if (modelClass.isAssignableFrom(ChatViewModel.class)) {
             try {
-                return modelClass.getConstructor(String.class, String.class).newInstance(userId, token);
+                return modelClass.getConstructor(String.class,String.class).newInstance(userId, token);
             } catch (InvocationTargetException | IllegalAccessException | InstantiationException |
                      NoSuchMethodException e) {
                 throw new RuntimeException(e);
diff --git a/app/src/main/java/com/example/tampopo_client/views/MainActivity.java b/app/src/main/java/com/example/tampopo_client/views/MainActivity.java
index 9911876..b9fea32 100644
--- a/app/src/main/java/com/example/tampopo_client/views/MainActivity.java
+++ b/app/src/main/java/com/example/tampopo_client/views/MainActivity.java
@@ -117,9 +117,10 @@
 
         //追加しました！！！！！！！！！！！
         // ChatViewModelを初期化する
-        ChatViewModelFactory factory1 = new ChatViewModelFactory(tampopo.getUserId(), tampopo.getToken(), tampopo.getChatroomId());
+        ChatViewModelFactory factory1 = new ChatViewModelFactory(tampopo.getUserId(), tampopo.getToken());
         chatViewModel = new ViewModelProvider(this, factory1).get(ChatViewModel.class);
 
+
         MutableLiveData<List<String>> friendsLiveData = activityViewModel.getFriendUserIdsLiveData();
 
         friendsLiveData.observe(this, new Observer<List<String>>() {