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1，一个简单的聊天窗口也是ListView显示的
首先是Main.xml是要建立一个列ListView，下面是输入框和发送按钮
然后是单独的消息列表项的界面
接着就是要建立一个自定义的适配器，搭建列表项和ListView之间的桥梁
具体的代码如下(注意LineraLayout布局，没说方向的时候默认是水平方向的，还有关于layout_weight权重的理解)：
activity_main.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:background="#d8e0e8"
android:orientation="vertical" >
<ListView
android:id="@+id/msg_list_view"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:divider="#0000" >
</ListView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<EditText
android:id="@+id/input_text"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="请输入一些数据"
android:maxLines="2" />
<Button
android:id="@+id/send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="发送" />
</LinearLayout>
</LinearLayout>然后是自定义的消息项
msg_item.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"
android:padding="10dp" >
<LinearLayout
android:id="@+id/left_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:background="@drawable/message_left" >
<TextView
android:id="@+id/left_msg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="10dp"
android:textColor="#fff" />
</LinearLayout>
<LinearLayout
android:id="@+id/right_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:background="@drawable/message_right" >
<TextView
android:id="@+id/right_msg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="10dp" />
</LinearLayout>
</LinearLayout>MessageAdapter
public class MessageAdapter extends ArrayAdapter<Message> {
private int resourceId;
public MessageAdapter(Context context, int resource, List<Message> objects) {
super(context, resource, objects);
// TODO Auto-generated constructor stub
resourceId = resource;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
/* return super.getView(position, convertView, parent); */
Message msg = getItem(position);
View view;
ViewHolder viewHolder;
if (convertView == null) {
view = LayoutInflater.from(getContext()).inflate(resourceId, null);
viewHolder = new ViewHolder();
viewHolder.leftLayout = (LinearLayout) view
.findViewById(R.id.left_layout);
viewHolder.rightLayout = (LinearLayout) view
.findViewById(R.id.right_layout);
viewHolder.leftMsg = (TextView) view.findViewById(R.id.left_msg);
viewHolder.rightMsg = (TextView) view.findViewById(R.id.right_msg);
view.setTag(viewHolder);
} else {
view = convertView;
viewHolder = (ViewHolder) view.getTag();
}
if (msg.getType()==Message.TYPE_RECEIVED) {
//如果是收到消息，就显示左边的布局，隐藏右边的消息布局
viewHolder.leftLayout.setVisibility(View.VISIBLE);
viewHolder.rightLayout.setVisibility(View.GONE);
viewHolder.leftMsg.setText(msg.getContent());
} else if(msg.getType()==Message.TYPE_SENT){
//如果是收到消息，就显示左边的布局，隐藏右边的消息布局
viewHolder.leftLayout.setVisibility(View.GONE);
viewHolder.rightLayout.setVisibility(View.VISIBLE);
viewHolder.rightMsg.setText(msg.getContent());
}
return view;
}
//列表子项实例类
class ViewHolder {
LinearLayout leftLayout;
LinearLayout rightLayout;
TextView leftMsg;
TextView rightMsg;
}
}注意该适配器类中有一个存放列表子项实例的类
最后就是MainActivity中初始化数据、构建适配器装载数据，将适配器加载到ListView项中
public class MainActivity extends Activity {
private ListView msgListView;
private EditText inputText;
private Button send;
private MessageAdapter adapter;
private List<Message> msgList=new ArrayList<Message>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
//初始化数据
initMsgs();
//将消息数据的xml格式文件加载打牌adapter，等待ListView把adapter装载起来
adapter=new MessageAdapter( MainActivity.this,R.layout.msg_item,msgList);
inputText=(EditText) findViewById(R.id.input_text);
send=(Button) findViewById(R.id.send);
msgListView=(ListView) findViewById(R.id.msg_list_view);
msgListView.setAdapter(adapter);
send.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String content=inputText.getText().toString();
if(!"".equals(content)){
Message msg=new Message(content, Message.TYPE_SENT);
msgList.add(msg);
<strong> //当有新消息的时候,刷新ListView中的显示
adapter.notifyDataSetChanged();
//将ListView定位到最后一行
msgListView.setSelection(msgList.size());</strong>
//清空输入框中的内容
inputText.setText("");
}
}
});
}
private void initMsgs() {
// TODO Auto-generated method stub
Message msg=new Message("你好xxx", Message.TYPE_RECEIVED);
Message msg1=new Message("Who are you，你谁呀", Message.TYPE_SENT);
Message msg2=new Message("初次见面，多多关照", Message.TYPE_RECEIVED);
msgList.add(msg);
msgList.add(msg1);
msgList.add(msg2);
}
附录：
下面用到的左右两个聊天背景，主要代码和素材都是来自“第一行代码”这本书
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原文地址：http://blog.csdn.net/hll174/article/details/45604751
