QQl聊天消息

package com.zzw.qqchat;

import java.util.ArrayList;
import java.util.HashMap;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends Activity {
private final int VIEW_TYPE = 0x001;
private final int MESSAGE = 0x002;

private final int VIEW_TYPE_LEFT = -1;
private final int VIEW_TYPE_RIGHT = -2;

private ArrayList<HashMap<Integer, Object>> items;
private MyAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

final ListView listView = (ListView) findViewById(R.id.list);

items = new ArrayList<HashMap<Integer, Object>>();

addData();

adapter = new MyAdapter(this, -1);
listView.setAdapter(adapter);

final EditText et = (EditText) findViewById(R.id.msgEditText);

findViewById(R.id.msgSend).setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
String msg = et.getText() + "";

HashMap<Integer, Object> map = new HashMap<Integer, Object>();
map.put(VIEW_TYPE, VIEW_TYPE_RIGHT);
map.put(MESSAGE, msg);
items.add(map);
// item数据变化时通知adapter刷新及时改变view
adapter.notifyDataSetChanged();
// 刷新后清空输入框
et.setText("");
// 输入框发送消息后将ListView滚动到底部
listView.setSelection(ListView.FOCUS_DOWN);

}
});
}

private void addData() {
for (int i = 0; i < 10; i++) {
if (i % 2 == 0) {
HashMap<Integer, Object> map = new HashMap<Integer, Object>();
map.put(VIEW_TYPE, VIEW_TYPE_LEFT);
map.put(MESSAGE, "对方说的消息:" + i);
items.add(map);
} else {
HashMap<Integer, Object> map = new HashMap<Integer, Object>();
map.put(VIEW_TYPE, VIEW_TYPE_RIGHT);
map.put(MESSAGE, "我说的消息:" + i);
items.add(map);
}
}
}

private class MyAdapter extends ArrayAdapter {
private LayoutInflater inflater;

public MyAdapter(Context context, int resource) {
super(context, resource);
inflater = LayoutInflater.from(context);
}

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

@Override
public String getItem(int position) {

String message = items.get(position).get(MESSAGE) + "";
return message;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

int type = getItemViewType(position);
String message = getItem(position);

switch (type) {
case VIEW_TYPE_LEFT:
if (convertView == null) {
convertView = inflater.inflate(R.layout.left, null);
}
TextView textViewLeft = (TextView) convertView.findViewById(R.id.textView);
textViewLeft.setText(message);
break;

case VIEW_TYPE_RIGHT:
if (convertView == null) {
convertView = inflater.inflate(R.layout.right, null);
}
TextView textViewRight = (TextView) convertView.findViewById(R.id.textView);
textViewRight.setText(message);
break;
}

return convertView;
}

@Override
public int getItemViewType(int position) {
HashMap map = items.get(position);
int type = (Integer) map.get(VIEW_TYPE);
return type;
}

@Override
public int getViewTypeCount() {
return 2;
}
}
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="@+id/commentLinearLayout"
android:layout_alignParentTop="true"
android:divider="@android:color/transparent"
android:dividerHeight="15dip"
android:scrollbars="none" />

<LinearLayout
android:id="@+id/commentLinearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="#e0e0e0"
android:orientation="horizontal" >

<EditText
android:id="@+id/msgEditText"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="8"
android:hint="发送消息" />

<Button
android:id="@+id/msgSend"
style="?android:attr/buttonStyleSmall"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="2"
android:text="发送" />
</LinearLayout>

</RelativeLayout>

activity_main

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >

<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:singleLine="false"
android:src="@drawable/ic_launcher" />

<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toRightOf="@+id/imageView"
android:background="#ff5252"
android:text="left" />

</RelativeLayout>

left

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >

<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:src="@drawable/ic_launcher" />

<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toLeftOf="@+id/imageView"
android:background="#2196f3"
android:singleLine="false"
android:text="right" />

</RelativeLayout>

right