聊天界面以及contextm

聊天界面，首先是布局，先用tools下的制作9patch图片的工具制作两张对话框图片，分别用作接收消息的图片背景和发送消息的图片背景。activity_main.xml的布局文件如下:

 <ListView        android:id="@+id/message_listview"        android:layout_width="match_parent"        android:layout_height="0dp"        android:layout_weight="1.0"        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="Type somthing here"            android:maxLines="2" />        <Button            android:id="@+id/send"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="发送"             android:background="#70CFEB"/>    </LinearLayout>

显而易见，利用ListView来显示发送的和接收的消息，既然有了ListView，所以还应该有一个ListView的Item布局,item布局如下:

<?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/im_bg_chat_content_other_side_pressed" >        <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/chat_content_self_bg" >        <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>

其中@drawable引用的图片就是我们制作的两张对话框9patch图片。

既然是聊天界面，又是用LIstView来显示，所以得新建一个Message的实体类，定义两个属性，content和type,并且进行封装.

public class Message {public static final int TYPE_SEND = 1;//发送方的唯一标识public static final int TYPE_RECEIVED = 0;//接收者的唯一标识private String Content;//消息的内容private int type;//消息的类别(是发送还是接收)public Message(String content, int type) {super();Content = content;this.type = type;}public String getContent() {return Content;}public void setContent(String content) {Content = content;}public int getType() {return type;}public void setType(int type) {this.type = type;}}

接下来就是写数据源适配器了，初学时ListView一般都是和ArrayAdapter和SimpleAdapter，我一直用的都是更加灵活的自定义Adapter。所以，新建一个适配器继承BaseAdapter.

public class MessageAdapter extends BaseAdapter {private List<Message> list;//Message类的集合private LayoutInflater inflater;public MessageAdapter(Context context) {list = new ArrayList<Message>();inflater = LayoutInflater.from(context);}public void addItem(Message msg) {list.add(msg);this.notifyDataSetChanged();}public void removeItem(int position){list.remove(position);}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn list.size();}@Overridepublic Object getItem(int position) {// TODO Auto-generated method stubreturn list.get(position);}@Overridepublic long getItemId(int position) {// TODO Auto-generated method stubreturn position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {// TODO Auto-generated method stubViewHolder holder = null;if (convertView == null) {convertView = inflater.inflate(R.layout.message_item, null);holder = new ViewHolder();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();}// 如果是收到的消息,则隐藏掉右边的布局if (list.get(position).getType() == Message.TYPE_RECEIVED) {holder.leftLayout.setVisibility(View.VISIBLE);holder.rightLayout.setVisibility(View.GONE);holder.leftMsg.setText(list.get(position).getContent());} else if (list.get(position).getType() == Message.TYPE_SEND) {//如果是发送的信息holder.leftLayout.setVisibility(View.GONE);holder.rightLayout.setVisibility(View.VISIBLE);holder.rightMsg.setText(list.get(position).getContent());}return convertView;}class ViewHolder {LinearLayout leftLayout;LinearLayout rightLayout;TextView leftMsg;TextView rightMsg;}}

最后，开始在Activity中编写。

/** * 聊天界面 * @author zcsolf *  */public class MainActivity extends Activity implements OnClickListener {private Button Send;private ListView ListMessage;private EditText Input;private MessageAdapter mAdapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);findView();InitMessage();ListMessage.setAdapter(mAdapter);ListMessage.setSelector(new ColorDrawable(Color.TRANSPARENT));//注册上下文菜单this.registerForContextMenu(ListMessage);}/** * 初始化消息,即模拟消息 */private void InitMessage() {// TODO Auto-generated method stubMessage msg;msg = new Message("Hello SB.", Message.TYPE_RECEIVED);mAdapter.addItem(msg);msg = new Message("你哪位?", Message.TYPE_SEND);mAdapter.addItem(msg);msg = new Message("我是XXXXXXX", Message.TYPE_RECEIVED);mAdapter.addItem(msg);}/** * 初始化组件 */private void findView() {// TODO Auto-generated method stubSend = (Button) findViewById(R.id.send);ListMessage = (ListView) findViewById(R.id.message_listview);Input = (EditText) findViewById(R.id.input_text);mAdapter = new MessageAdapter(MainActivity.this);Send.setOnClickListener(this);}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.send:String content = Input.getText().toString();if (!"".equals(content)) {Message msg = new Message(content, Message.TYPE_SEND);mAdapter.addItem(msg);mAdapter.notifyDataSetChanged(); // 当有新消息时，刷新ListView中的显示ListMessage.setSelection(mAdapter.getCount()); // 将ListView定位到最后一行Input.setText(""); // 清空输入框中的内容}break;default:break;}}/** * 生成上下文菜单 */@Overridepublic void onCreateContextMenu(ContextMenu menu, View v,ContextMenuInfo menuInfo) {super.onCreateContextMenu(menu, v, menuInfo);menu.setHeaderTitle("短信管理");menu.add(0, 1, Menu.NONE, "复制");menu.add(0, 2, Menu.NONE, "删除");}/** * 响应上下文菜单 */@Overridepublic boolean onContextItemSelected(MenuItem item) {//ContextMenuInfo的适配器AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo) item.getMenuInfo();Log.v("SampleContextMenuActivity", "context item seleted ID="+ menuInfo.id);switch (item.getItemId()) {case 1:Toast.makeText(MainActivity.this, "复制", Toast.LENGTH_SHORT).show();break;case 2:Toast.makeText(MainActivity.this, "删除", Toast.LENGTH_SHORT).show();break;default:break;}return true;}}