RecyclerView再記錄

    最近開發用到了關於RecyclerView的知識，覺得了解還不夠深刻，再將demo記錄一遍加深記憶。按照自己對RecyclerView流程的感受：在MainActivity中對RecyclerView組件進行聲明，之後實例化一個LinerLayoutManager佈局管理器，使用setLayoutManager對其進行處理，再實例化一個adapter適配器，用setAdapter進行處理。
    首先，根據自己的業務需求創建entity實體類。包名略過

public class Msg {
    public static final int TYPE_RECEIVED = 0;
    public static final int TYPE_SEND = 1;

    private String content;
    private int type;

    public Msg(String content, int type) {
        this.content = content;
        this.type = type;
    }

    public String getContent() {
        return content;
    }

    public int getType() {
        return type;
    }

}

    之後，編寫適合項目的適配器並使其繼承RecyclerView.Adapter

public class MsgAdapter extends RecyclerView.Adapter<MsgAdapter.ViewHolder>{
    private List<Msg> mMsgList;

    static class ViewHolder extends RecyclerView.ViewHolder{
        LinearLayout leftLayout;
        LinearLayout rightLayout;
        TextView leftMsg;
        TextView rightMsg;

        public ViewHolder(View view){
            super(view);
            leftLayout = (LinearLayout) view.findViewById(R.id.left_layout);
            rightLayout = (LinearLayout) view.findViewById(R.id.right_layout);
            leftMsg = (TextView) view.findViewById(R.id.left_msg);
            rightMsg = (TextView) view.findViewById(R.id.right_msg);
        }
    }

    public MsgAdapter(List<Msg> msgList){
        mMsgList = msgList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Msg msg = mMsgList.get(position);

        if (msg.getType() == Msg.TYPE_RECEIVED){
            holder.leftLayout.setVisibility(View.VISIBLE);
            holder.rightLayout.setVisibility(View.GONE);
            holder.leftMsg.setText(msg.getContent());
        } else if(msg.getType() == Msg.TYPE_SEND){
            holder.rightLayout.setVisibility(View.VISIBLE);
            holder.leftLayout.setVisibility(View.GONE);
            holder.rightMsg.setText(msg.getContent());
        }
    }

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

因爲項目涉及到線程相關的知識，所以將MainActivity中的代碼置於線程池。

  private void showInfo(final String text,final String answer) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                System.out.println("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!!!");
                LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
                msgRecyclerView.setLayoutManager(layoutManager);
                adapter = new MsgAdapter(msgList);
                msgRecyclerView.setAdapter(adapter);
                Msg msg1 = new Msg(text, Msg.TYPE_RECEIVED);
                msgList.add(msg1);
                Msg msg2 = new Msg(answer, Msg.TYPE_SEND);
                msgList.add(msg2);
                //若有新的消息進入，定位並滾動至新消息位置
                adapter.notifyItemInserted(msgList.size() - 1);
                msgRecyclerView.scrollToPosition(msgList.size() - 1);
            }
        });
    }

 

    這裏存在一個未解決的問題：若在MainActivity中通過Intent啓動別的活動，再返回主活動時會出現繼續創建新線程的問題，此線程池內的代碼會被二次調用，有待排查，抽空寫這邊博客的目的就是理清思路，在之後的故障排查中找到屬於自己的感覺。