MsgAdapter.java

package com.bigfat.uibestpractice;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.List;

/**
 * @author <a href="mailto:fbzhh007@gmail.com">bigfat</a>
 * @since 2014/12/6
 */
public class MsgAdapter extends ArrayAdapter<Msg> {
    private int resourceId;

    public MsgAdapter(Context context, int textViewResourceId, List<Msg> objects) {
        super(context, textViewResourceId, objects);
        resourceId = textViewResourceId;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Msg msg = getItem(position);
        ViewHolder holder;
        if (convertView == null) {
            holder = new ViewHolder();
            convertView = LayoutInflater.from(getContext()).inflate(resourceId, null);
            holder.leftLayout = (LinearLayout) convertView.findViewById(R.id.left_layout);
            holder.rightLayout = (LinearLayout) convertView.findViewById(R.id.right_layout);
            holder.leftMsg = (TextView) convertView.findViewById(R.id.left_msg);
            holder.rightMsg = (TextView) convertView.findViewById(R.id.right_msg);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        //判断显示消息类别
        if (msg.getType() == Msg.TYPE_RECEIVED) {
            holder.leftLayout.setVisibility(View.VISIBLE);
            holder.rightLayout.setVisibility(View.GONE);
            holder.leftMsg.setText(msg.getContent());
        } else {
            holder.leftLayout.setVisibility(View.GONE);
            holder.rightLayout.setVisibility(View.VISIBLE);
            holder.rightMsg.setText(msg.getContent());
        }
        return convertView;
    }

    private final class ViewHolder {
        LinearLayout leftLayout;
        LinearLayout rightLayout;
        TextView leftMsg;
        TextView rightMsg;
    }
}