【发布时间】：2012-02-04 01:56:18
【问题描述】：
我正在通过与 .net Web 服务通信来开发示例应用程序。在我的应用程序中，我将来自 Web 服务的记录获取到我的活动类中，然后我使用 ArrayAdapter 在 ListView 中显示整个记录，并且我正在运行一项服务当新记录可从 Web 服务获得时，后台进程中的类用于从 Web 服务获取最新记录，然后我将这些记录保存到 SQLite 数据库中。此过程在后台发生。在这里我想获取最新数据从 SQLite DB 并附加到我的 ListView。 我已经实现了 Activity 类如下：
public class GetMsgsScreen extends ListActivity
{
private LayoutInflater mInflater;
private Vector<RowData> data;
RowData rd;
static String[] userName = null;
static String[] usrMessages = null;
private Integer[] imgid = null;
ShoutRepeatService bg;
////////////////////////////////////////////////////
List<Message> resultShoutMessage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
resultMessage = new ParseXml().convertMessages(new Model().getMessages("0"));
usrMessages = new String[resultMessage.size()];
userName = new String[resultMessage.size()];
imgid = new Integer[resultMessage.size()];
getSharedPreferences("Values", 0).edit().putString("msgid",resultMessage.get(0).getMessageID()).commit();
for(int i=0;i<resultMessage.size();i++)
{
Log.v("GetMsgsScreen", "resultMessage*******>>>>"+resultMessage.get(i).getMessageText());
Log.v("GetMsgsScreen", "resultNames*******>>>>"+resultMessage.get(i).getUserFirstName());
usrMessages[i] = resultMessage.get(i).getMessageText();
userName[i] = resultMessage.get(i).getUserFirstName();
imgid[i] = R.drawable.person;
}
///////////////////////////////////////////////////////
mInflater = (LayoutInflater) getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
data = new Vector<RowData>();
for(int i=0;i<userName.length;i++){
try {
rd = new RowData(i,userName[i],usrMessages[i]);
} catch (ParseException e) {
e.printStackTrace();
}
data.add(rd);
}
CustomAdapter adapter = new CustomAdapter(this, R.layout.list, R.id.usrName, data);
setListAdapter(adapter);
bindService(new Intent(GetMsgsScreen.this, RepeatService.class), mConnection, Context.BIND_AUTO_CREATE);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
getListView().setTextFilterEnabled(true);
}
@Override
protected void onDestroy() {
unbindService(mConnection);
super.onDestroy();
}
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder binder) {
bg = ((RepeatService.MyBinder) binder).getService();
Toast.makeText(GetMsgsScreen.this, "Connected",
Toast.LENGTH_SHORT).show();
}
public void onServiceDisconnected(ComponentName className) {
bg = null;
}
};
public void onListItemClick(ListView parent, View v, int position, long id) {
Toast.makeText(getApplicationContext(), "You have selected "
+(position+1)+"th item", Toast.LENGTH_SHORT).show();
}
private class CustomAdapter extends ArrayAdapter<RowData> {
public CustomAdapter(Context context, int resource, int textViewResourceId, List<RowData> objects) {
super(context, resource, textViewResourceId, objects);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
TextView name = null;
TextView messages = null;
ImageView i11=null;
RowData rowData= getItem(position);
if(null == convertView){
convertView = mInflater.inflate(R.layout.list, null);
holder = new ViewHolder(convertView);
convertView.setTag(holder);
}
holder = (ViewHolder) convertView.getTag();
name = holder.gettitle();
name.setText(rowData.mName);
messages = holder.getdetail();
messages.setText(rowData.mMessage);
i11=holder.getImage();
i11.setImageResource(imgid[rowData.mId]);
return convertView;
}
private class ViewHolder {
private View mRow;
private TextView names = null;
private TextView messageText = null;
private ImageView i11=null;
public ViewHolder(View row) {
mRow = row;
}
public TextView gettitle() {
if(null == names){
names = (TextView) mRow.findViewById(R.id.usrName);
}
return names;
}
public TextView getdetail() {
if(null == messageText){
messageText = (TextView) mRow.findViewById(R.id.msgText);
}
return messageText;
}
public ImageView getImage() {
if(null == i11){
i11 = (ImageView) mRow.findViewById(R.id.img);
}
return i11;
}
}
}
}
我已经实现了后台服务类如下：
public class RepeatService extends Service
{
List<Message> resultMessage;
String[] userNameLatest = null;
String[] usrMessagesLatest = null;
String[] usrMessageID = null;
String msgID = null;
private Timer timer = new Timer();
private static final long UPDATE_INTERVAL = 500;
SQLiteDB db;
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public void onCreate() {
pollForUpdates();
super.onCreate();
}
private void pollForUpdates() {
timer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
Log.v("!!!!!!!!!!!!!!!!", "service is calling");
msgID = getSharedPreferences("Values", 0).getString("msgid","");
resultMessage = new ParseXml().convertMessages(new Model().getMessages(msgID));
usrMessagesLatest = new String[resultMessage.size()];
userNameLatest = new String[resultMessage.size()];
usrMessageID = new String[resultMessage.size()];
db = new SQLiteDB();
for(int i=0;i<resultMessage.size();i++)
{
Log.v("RepeatService", "getMessageID------>"+resultMessage.get(i).getMessageID());
Log.v("RepeatService", "getMessageText------>"+resultMessage.get(i).getMessageText());
Log.v("RepeatService", "getUserFirstName------>"+resultMessage.get(i).getUserFirstName());
usrMessagesLatest[i] = resultMessage.get(i).getMessageText();
userNameLatest[i] = resultMessage.get(i).getUserFirstName();
usrMessageID[i] = resultMessage.get(i).getMessageID();
//Save the data into Sqlite db here
db.insertValues(usrMessageID[i], userNameLatest[i], usrMessagesLatest[i], RepeatService.this);
}
}
}, 0, UPDATE_INTERVAL);
Log.v(getClass().getSimpleName(), "Timer started.");
}
public class MyBinder extends Binder {
ShoutRepeatService getService()
{
return ShoutRepeatService.this;
}
}
}
如果 Web 服务有任何新记录可用，则上述类始终在后台运行，然后将记录存储到 Sqlite 数据库中。
从上面的代码中，我可以将数据保存到 Sqlite 数据库中 如何在 My Activity 类的 ListView 中显示最新记录？
请任何人帮助我解释代码.........
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