listview的一个聊天界面

时间：2021-09-30 19:36:19


1.首先是一个项的布局文件 -----item_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
<LinearLayout
    android:id="@+id/left_layout"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="left"
    android:background="@drawable/msg"
    android:layout_marginLeft="10dp">
<TextView
    android:id="@+id/tv_left"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
</LinearLayout>
    <LinearLayout
        android:id="@+id/right_layout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="right"
        android:background="@drawable/msg">
    <TextView
        android:id="@+id/tv_right"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"/>
    </LinearLayout>

</LinearLayout>
2.第2步消息实体类Msg
package com.example.myapplication;

/**msg 消息实体类
 * Created by Administrator on 2015/8/1.
 */
public class Msg {
public static final int TYPE_RECEIVER=0;
    public  static final int TYPE_SEND=1;

    private String content;//短信的内容
    private int type;

    @Override
    public String toString() {
return super.toString();
    }

public Msg() {
super();
    }

public Msg(String content, int type) {

this.content = content;
        this.type = type;
    }

public String getContent() {
return content;
    }

public void setContent(String content) {
this.content = content;
    }

public int getType() {
return type;
    }

public void setType(int type) {
this.type = type;
    }
}
3 ArrayAdapter的自定义
package com.example.myapplication;

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;

/**
 * Created by Administrator on 2015/8/1.
 */
public class MsgAdapter extends ArrayAdapter<Msg> {

private Context context;
    private int resourceId;
    private List<Msg> list;
    public MsgAdapter(Context context,int resourceId,List<Msg> list){
super(context,resourceId,list);
        this.context=context;
        this.resourceId=resourceId;
        this.list=list;
    }

@Override
    public View getView(int position, View convertView, ViewGroup parent) {
//
        ViewHolder viewHolder=null;
        Msg msg=getItem(position);
        if (convertView==null){
//加载布局
            viewHolder=new ViewHolder();
            convertView=LayoutInflater.from(getContext()).inflate(R.layout.item_layout,null);
            //查找控件
            viewHolder.left_layout=(LinearLayout)convertView.findViewById(R.id.left_layout);
            viewHolder.right_layout=(LinearLayout)convertView.findViewById(R.id.right_layout);
            viewHolder.tv_left=(TextView)convertView.findViewById(R.id.tv_left);
            viewHolder.tv_right=(TextView)convertView.findViewById(R.id.tv_right);

            convertView.setTag(viewHolder);
        }else{
//直接获取
           viewHolder=(ViewHolder)convertView.getTag();
        }
if (msg.getType()==Msg.TYPE_RECEIVER)//如果它是接收消息 就放左边
        {
//显示左边 隐藏右边
            viewHolder.left_layout.setVisibility(View.VISIBLE);
            viewHolder.right_layout.setVisibility(View.GONE);
            //设置左边的内容
            viewHolder.tv_left.setText(msg.getContent());
        }else{
//显示右边 隐藏左边
            viewHolder.left_layout.setVisibility(View.GONE);
            viewHolder.right_layout.setVisibility(View.VISIBLE);
            //设置右边的内容
            viewHolder.tv_right.setText(msg.getContent());
        }
return convertView;
    }

static class ViewHolder{

static LinearLayout left_layout;
        static LinearLayout right_layout;
        static TextView tv_left;
        static TextView tv_right;
    }
}
4.activity的显示
package com.example.myapplication;

import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

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


public class MainActivity extends Activity {
private ListView listView;
    private MsgAdapter adapter=null;
    private List<Msg> list=null;
    private EditText et_content;
    private Button btn_send;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);//去掉标题
        setContentView(R.layout.activity_main);
        //初始化控件
        findView();
        list=new ArrayList<Msg>();
        initData();//初始化数据 将数据添加到容器中
        //将数据放入到适配器中
        adapter=new MsgAdapter(MainActivity.this,R.layout.item_layout,list);
        listView.setAdapter(adapter);
        //按钮的监听事件
        btn_send.setOnClickListener(new View.OnClickListener() {
@Override
            public void onClick(View view) {
//
                String content=et_content.getText().toString().trim();

                //判空
                if (TextUtils.isEmpty(content)){
                    Toast.makeText(getApplication(),"你输入的内容为空",Toast.LENGTH_SHORT).show();
                }else {
//不为空
                    Msg msg=new Msg(content,Msg.TYPE_SEND);
                    list.add(msg);
                    //刷新消息
                    adapter.notifyDataSetChanged();
                    listView.setSelection(list.size());//将listview定位到最后一行
                    et_content.setText("");//清空
                }
            }
        });
    }



public void findView(){
listView=(ListView)findViewById(R.id.listview);
        et_content=(EditText)findViewById(R.id.et_content);
        btn_send=(Button)findViewById(R.id.btn_send);
    }
public void initData(){

        Msg msg1=new Msg("你好！",Msg.TYPE_RECEIVER);
        list.add(msg1);
        Msg msg2=new Msg("您也好啊！",Msg.TYPE_SEND);
        list.add(msg2);
        Msg msg3=new Msg("有什么事吗",Msg.TYPE_RECEIVER);
        list.add(msg3);
    }
}

 



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