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android应用程序后台管理与界面设计说说如何使用 Android UI 设计聊天界面(3)

电脑杂谈　发布时间：2018-02-22 00:41:49　来源：网络整理

我们让收到的消息居左对齐，发送的消息居右对齐，并分别使用刚才制作两张 9-patch png 作为背景图。

下面创建 RecyclerView 的适配器类：

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

    private List<Msg> msgList;

    static class ViewHolder extends RecyclerView.ViewHolder {

        LinearLayout leftLayout;
        LinearLayout rightLayout;

        TextView leftMsg;
        TextView rightMsg;

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

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

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

    @Override
    public void onBindViewHolder(MsgAdapter.ViewHolder holder, int position) {
        Msg msg=msgList.get(position);
        switch (msg.getType()){
            case RECEIVED://接收的消息
                holder.leftLayout.setVisibility(View.VISIBLE);
                holder.rightLayout.setVisibility(View.GONE);
                holder.leftMsg.setText(msg.getContent());
                break;
            case SENT://发出的消息
                holder.leftLayout.setVisibility(View.GONE);
                holder.rightLayout.setVisibility(View.VISIBLE);
                holder.rightMsg.setText(msg.getContent());
                break;
        }
    }

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