muil_item

//MainActivity

package com.example.mutil_item;

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class MainActivity extends AppCompatActivity {
    private MassageAdapter mAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ListView listView = findViewById(R.id.messages);

        mAdapter = new MassageAdapter(this);
        listView.setAdapter(mAdapter);

        asy();
    }
    private  void asy(){
        new AsyncTask<Random,Void,List<MassageBean>>(){

            @Override
            protected List<MassageBean> doInBackground(Random... voids) {
                List<MassageBean> result = new ArrayList<>();

                //Random random = new Random();

                for (int i = 0; i < 30; i++) {
                    result.add(new MassageBean("消息："+i,voids[0].nextBoolean()));
                }
                return result;
            }

            @Override
            protected void onPostExecute(List<MassageBean> massageBeans) {
                mAdapter.setList(massageBeans);
            }
        }.execute(new Random());
    }
}

//MassageAdapter

package com.example.mutil_item;

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

import java.util.ArrayList;
import java.util.List;

public class MassageAdapter extends BaseAdapter {
    private List<MassageBean> mdatas;
    private Context context;

    //总共有两种条目
    private final int ITEM_COUNT = 2;
    private final int LEFT_ITEM  = 0;
    private final int RIGHT_ITEM = 1;
    @Override
    public int getItemViewType(int position) {
        if (getItem(position).isRec()){
            return LEFT_ITEM;
        }else {
            return RIGHT_ITEM;
        }
    }

    @Override
    public int getViewTypeCount() {
        return ITEM_COUNT;
    }

    public MassageAdapter(Context context) {
        this.context = context;
        mdatas  =new ArrayList<>();
    }

    public  void  setList(List<MassageBean> datas){
        this.mdatas = datas;
        notifyDataSetChanged();
    }


    @Override
    public int getCount() {
        return mdatas.size();
    }

    @Override
    public MassageBean getItem(int position) {
        return mdatas.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null){
            holder = new ViewHolder();
            convertView = LayoutInflater.from(context).inflate(

                getItemViewType(position) == LEFT_ITEM?R.layout.left_item:R.layout.right_item

                ,parent,false);
            holder.massage = convertView.findViewById(R.id.massage);
            convertView.setTag(holder);
        }else {
            holder = (ViewHolder) convertView.getTag();
        }
        holder.massage.setText(getItem(position).getMassage());

        return convertView;
    }
    class ViewHolder{
        private TextView massage;
    }
}

//bean

package com.example.mutil_item;

public class MassageBean {

    private  String massage;
    private boolean isRec;

    public MassageBean(String massage, boolean isRec) {
        this.massage = massage;
        this.isRec = isRec;
    }

    public String getMassage() { return massage; }

    public void setMassage(String massage) {
        this.massage = massage;
    }

    public boolean isRec() {
        return isRec;
    }

    public void setRec(boolean rec) {
        isRec = rec;
    }
}