我是Android的新手。在我的應用程序中,我創建了多對多聊天,並且需要從服務器更新消息列表。爲了做到這一點,我創建了一項服務,每秒更新一次服務器。如何以正確的方式在服務和應用程序之間傳遞數據?
我的問題是,我不知道如何將數據傳回應用程序。我知道我應該使用意圖和廣播接收器來做到這一點,但是我堅持使用Bundle對象,我必須序列化才能將它傳遞給應用程序,並且這對我沒有意義,因爲此操作不是高效。
現在我正在使用引用到我的應用程序(我認爲這不是很好,但不知道爲什麼),並且在每次從服務器更新服務之後,我激活應用程序功能,並直接更新它的字段。而且我想也許我的代碼會做一些適合初學者以及:)
public class UpdateChatService extends Service {
private static final long DELAY_FOR_CHAT_TASK = 0;
private static final long PERIOD_FOR_CHAT_TASK = 1;
private static final TimeUnit TIME_UNIT_CHAT_TASK = TimeUnit.SECONDS;
//private Task retryTask; TODO: check this out
private ScheduledExecutorService scheduler;
private boolean timerRunning = false;
private long RETRY_TIME = 200000;
private long START_TIME = 5000;
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
scheduleChatUpdate();
}
private void scheduleChatUpdate() {
BiggerGameApp app = (BiggerGameApp) getApplication();
this.scheduler = Executors.newScheduledThreadPool(3);
this.scheduler.scheduleAtFixedRate(new UpdateChatTask(app),
DELAY_FOR_CHAT_TASK, PERIOD_FOR_CHAT_TASK,
TIME_UNIT_CHAT_TASK);
timerRunning = true;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
if (!timerRunning) {
scheduleChatUpdate();
}
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
super.onDestroy();
if (scheduler != null) {
scheduler.shutdown();
}
timerRunning = false;
}
}
這裏是異步任務的代碼在服務的運行。 請告訴我我做錯了什麼,以及如何將數據從服務傳遞到應用程序。
public void run() {
try {
if (this.app.getLastMsgFromServer() == null) {
this.app.setLastMsgFromServer(new Message(new Player(DEFAULT_EMAIL), "", -1));
this.app.getLastMsgFromServer().setMessageId(-1);
}
Gson gson = new GsonBuilder()
.registerTypeAdapter(DateTime.class, new DateTimeTypeConverter())
.create();
ServerHandler serverHandler = new ServerHandler();
String jsonString = gson.toJson(this.app.getLastMsgFromServer());
// Sending player to servlet in server
String resultString = serverHandler.getResultFromServlet(jsonString, "GetListOfMessages");
if (resultString.contains("Error")) {
return;
}
// Parsing answer
JSONObject json = new JSONObject(resultString);
Status status = null;
String statusString = json.getString("status");
if (statusString == null || statusString.length() == 0)
return;
status = Status.valueOf(statusString);
if (Status.SUCCESS.equals(status)) {
ArrayList<Message> tempChat = null;
JSONArray jsonList = json.getJSONArray("data");
MyJsonParser jsonParser = new MyJsonParser();
tempChat = jsonParser.getListOfMessagesFromJson(jsonList.toString());
if (tempChat != null && tempChat.size() != 0) {
// After getting the chat from the server, it saves the last msg
// For next syncing with the server
this.app.setLastMsgFromServer(tempChat.get(LAST_MSG_INDEX));
tempChat.addAll(this.app.getChat());
if (tempChat.size() > SIZE_OF_USER_CHAT) {
tempChat = (ArrayList<Message>) tempChat.subList(0, SIZE_OF_USER_CHAT - 1);
}
this.app.setChat(tempChat);
this.app.updateViews(null);
}
}
return;