1. Main functions:

①Realization of chat interface

② Status bar immersion

③ The soft keyboard pops up automatically

④ ScrollView automatically scrolls after sending a message, and makes EditText get the focus again

2. On the previous interface, see if it meets your needs. If it matches, continue to look down

3. The main interface is implemented in MainActivity

//onCreate

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {//Immersive status bar implementation
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
        }
 getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);//Automatically recalculate the layout after the soft keyboard pops up

scrollView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {//Registration event for scrollview registration layout change
            @Override
            public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
                if (mHandler != null) {
                    mHandler.post(new Runnable() {
                        @Override
                        public void run() {
                                                         scrollView.fullScroll(FOCUS_DOWN);//scrollView automatically slide to the bottom
                                                         msg.setFocusable(true);//The next thing is to return focus to EditText
                            msg.setFocusableInTouchMode(true);
                            msg.requestFocus();
                            msg.findFocus();
                        }
                    });
                }
            }
        });

4. Realization of immersive status bar

The root layout is focused on fitsSysytemWindows="true"

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/main_color"
    android:fitsSystemWindows="true">   

5. Classification of chat content

private class ChatMsgAdapter extends RecyclerView.Adapter<ChatMsgAdapter.ViewHolder> {

        private ArrayList<MsgChatBody> list;

        public ChatMsgAdapter(ArrayList<MsgChatBody> list) {
            this.list = list;
        }

        class ViewHolder extends RecyclerView.ViewHolder {
            public View view;
            public TextView chatMsgLeft;
            public TextView chatMsgRight;

            public ViewHolder(View itemView) {
                super(itemView);
                view = itemView;
                                 chatMsgLeft = view.findViewById(R.id.chat_msg_left);//The layout on the left
                                 chatMsgRight = view.findViewById(R.id.chat_msg_right);//right layout
            }
        }

        @NonNull
        @Override
        public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.chat_msg_content,
                    parent, false);
            ViewHolder viewHolder = new ViewHolder(view);
            return viewHolder;
        }

        @Override
        public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
            MsgChatBody body = list.get(position);
                         if (body.type == CHAT_MSG_TYPE_LEFT) {//Judging by the type field, which layout is displayed
                holder.chatMsgRight.setVisibility(View.GONE);
                holder.chatMsgLeft.setVisibility(VISIBLE);
                holder.chatMsgLeft.setText(body.msg);
            } else if (body.type == CHAT_MSG_TYPE_RIGHT) {
                holder.chatMsgLeft.setVisibility(View.GONE);
                holder.chatMsgRight.setVisibility(VISIBLE);
                holder.chatMsgRight.setText(body.msg);
            }
        }

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

6.github address

A simple chat app interface implementation