Android recyclerView updata all list data still merge with old data

Question

  public  RecyclerView.Adapter mAdapter;
  public RecyclerView mMessagesView;

this is my list

public List<MessageList> Message_List = new ArrayList<MessageList>();

and this is my adapter

    mAdapter = new MessageAdapter1(getApplicationContext(), Message_List);
    mMessagesView = (RecyclerView) findViewById(R.id.messages);
    mMessagesView.setLayoutManager(new LinearLayoutManager(this));
    mMessagesView.setAdapter(mAdapter);

now i add some data on it

    Message_List.add(messageList);
    mAdapter.notifyItemInserted(Message_List.size() - 1);

its work without problems now i want to change all Message_List data and show in in recyvlerView i do this

public void swap(List<MessageList> datas){
    Message_List.clear();
    Message_List.addAll(datas);
    mAdapter.notifyDataSetChanged();

}

here i replace all data in Message_List and notifyDataSetChanged now its shown new data of Message_List

empty Message_List show blank

but when i try add new item to list and notify adapter its shown to me some of old item i removed it from Message_List and in LOG i watch it no old data there

now this is image before update Message_List data

now change Message_List data and notify

like we see blank because there are no data on Message_List

now try add new item to Message_List and notify adapter

 Message_List.add(balabala data);
 mAdapter.notifyItemInserted(Message_List.size() - 1);

and result must be without old data

for more information this is my MessageList class

public class MessageList {
public static final int TYPE_MESSAGE_RIGHT = 0;
public static final int TYPE_MESSAGE_LEFT = 1;
public static final int TYPE_ACTION = 2;
public static final String TYPING = "typing";
private String message, thumbnailUrl;
private String date;
private int user_id;
private boolean status = false;
private String fname;
private String direction;
private ArrayList<String> messageList;

public MessageList() {
    setMessageStatus(status);
}

public MessageList(String name, String thumbnailUrl, String date, String direction,
                   ArrayList<String> messageList, String fname, int user_id) {
    this.message = name;
    this.thumbnailUrl = thumbnailUrl;
    this.date = date;
    this.direction = direction;
    this.messageList = messageList;
    this.fname = fname;
    this.user_id = user_id;


}

public String getMessage() {
    return message;
}
public String getFname() {
    return fname;
}

public void setMessage(String message) {
    this.message = message;
}

public String getThumbnailUrl() {
    return thumbnailUrl;
}

public void setThumbnailUrl(String thumbnailUrl) {
    this.thumbnailUrl = thumbnailUrl;
}

public String getDate() {
    return date;
}


public boolean getMessageStatus() {
    return status;
}

public void setMessageStatus(boolean status) {
    this.status = status;
}


public int getUser_id() {
    return user_id;
}

public void setUser_id(int user_id) {
    this.user_id = user_id;
}

public void setDate(String date) {
    this.date = date;
}

public void setFname(String fname) {
    this.fname = fname;
}

public String getDir() {
    return direction;
}

public void setDir(String direction) {
    this.direction = direction;
}

public ArrayList<String> getMessageList() {
    return messageList;
}

public void setMessageList(ArrayList<String> messageList) {
    this.messageList = messageList;
}

}

and this is my adapter

 public class MessageAdapter1 extends RecyclerView.Adapter<MessageAdapter1.ViewHolder> {

private List<MessageList> mMessages;
private int[] mUsernameColors;
private Context context;

public MessageAdapter1(Context context, List<MessageList> messages) {  
    mMessages = messages;
    this.context = context;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    int layout = -1;

    int type = -1;
    if(mMessages.get(viewType).getDir().equals("left"))         type = 1;
    else if(mMessages.get(viewType).getDir().equals("right"))   type = 0;
    else if(mMessages.get(viewType).getDir().equals("typing"))  type = 2;


    switch (type) {
    case MessageList.TYPE_MESSAGE_RIGHT:
        layout = R.layout.right_message;
        break;
    case MessageList.TYPE_MESSAGE_LEFT:
        layout = R.layout.left_message;
        break;
    case MessageList.TYPE_ACTION:
        layout = R.layout.message_left;
        break;
    }

    View v = LayoutInflater.from(parent.getContext()).inflate(layout, parent, false);

    return new ViewHolder(v);
}

@Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
    MessageList message = mMessages.get(position);


    viewHolder.setGroupMessage(message);
}

@Override
public int getItemCount() {
    return mMessages.size();
}



@Override
public int getItemViewType(int position) {

    return position;
}




public class ViewHolder extends RecyclerView.ViewHolder {

    private LinearLayout groupMessage;
    //private ImageView   typing;
    public ViewHolder(View itemView) {
        super(itemView);

        groupMessage = (LinearLayout)itemView.findViewById(R.id.messages);

    }

    public void setGroupMessage(MessageList m) {


        if (null == groupMessage) return;

        int i = 0;

        if(m.getMessageStatus() == false){
          m.setMessageStatus(true);
            for (String message : m.getMessageList()) {

                //TextView text = new TextView(activity);
                TextView text = new MyTextView(context);
                LinearLayout.LayoutParams p = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
                p.setMargins(0, 0, 0, 2);

                if (m.getDir().equals("left")) {

                    text.setTextColor(Color.BLACK);
                    p.gravity = Gravity.LEFT;
                    if(m.getMessageList().size() == 1){
                        text.setBackgroundResource(R.drawable.message_left_default);
                    }
                    else if (i == 0) {
                        text.setBackgroundResource(R.drawable.message_left_first);
                    } else if (i + 1 == m.getMessageList().size()) {
                        text.setBackgroundResource(R.drawable.message_left_last);
                    } else {
                        text.setBackgroundResource(R.drawable.message_left);
                    }


                } else{

                    p.gravity = Gravity.RIGHT;
                    text.setTextColor(Color.WHITE);

                    if(m.getMessageList().size() == 1){
                        text.setBackgroundResource(R.drawable.message_right_default);
                    }
                    else if (i == 0) {
                        text.setBackgroundResource(R.drawable.message_right_first);
                    } else if (i + 1 == m.getMessageList().size()) {
                        text.setBackgroundResource(R.drawable.message_right_last);
                    } else {
                        text.setBackgroundResource(R.drawable.message_right);
                    }

                }


                text.setLayoutParams(p);
                text.setText(message);
                text.setPadding(8, 8, 8, 8);

                text.setTextSize(18f);



                //text.setTextAppearance(context, android.R.style.TextAppearance_Large);
                groupMessage.addView(text);
                i++;
            }

        }




    }



}
}

@UğurB `@Override public int getItemCount() { return mMessages.size(); }` — medo, Jul 30 '16 at 14:03
Please once check at below link: http://stackoverflow.com/questions/26635841/recyclerview-change-data-set — ViramP, Jul 30 '16 at 14:26

ugur · Answer 1 · 2016-07-30T14:57:56.750

the problem is there is no connection between mMessages and Message_List. To achieve this, put swap() in the adapter class and call it from the activity or fragment.

       public class MessageAdapter1 extends RecyclerView.Adapter<MessageAdapter1.ViewHolder> {

           ...

                public void swap(List<MessageList> datas){
                    mMessages.clear();
                    mMessages.addAll(datas);
                    notifyDataSetChanged();
                }


                public void add(MessageList data){
                        mMessages.add(data);
                        notifyItemInserted(mMessages.size() - 1);    
                }

      }

and from fragment or activity:

((MessageAdapter1) rv.getAdapter).add(data);

((MessageAdapter1) rv.getAdapter).swap(Message_List);

i add the function to adapter class but i cant access it ! `adapter.swap(Message_List);` — medo, Jul 30 '16 at 14:26

Android recyclerView updata all list data still merge with old data

1 Answers1