RecyclerView再记录

最近开发用到了关于RecyclerView的知识，觉得了解还不够深刻，再将demo记录一遍加深记忆。按照自己对RecyclerView流程的感受：在MainActivity中对RecyclerView组件进行声明，之后实例化一个LinerLayoutManager布局管理器，使用setLayoutManager对其进行处理，再实例化一个adapter适配器，用setAdapter进行处理。
首先，根据自己的业务需求创建entity实体类。包名略过

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;
    }

}

之后，编写适合项目的适配器并使其继承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();
    }
}

因为项目涉及到线程相关的知识，所以将MainActivity中的代码置于线程池。

  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);
                //若有新的消息进入，定位并滚动至新消息位置
                adapter.notifyItemInserted(msgList.size() - 1);
                msgRecyclerView.scrollToPosition(msgList.size() - 1);
            }
        });
    }

这里存在一个未解决的问题：若在MainActivity中通过Intent启动别的活动，再返回主活动时会出现继续创建新线程的问题，此线程池内的代码会被二次调用，有待排查，抽空写这边博客的目的就是理清思路，在之后的故障排查中找到属于自己的感觉。

猜你喜欢