从android中的Service调用BroadCastReceiver来更新Fragment中的UI？

Question

我想更新UI一个fragmentfrom service.我正在使用GCM发送消息.我有这个类GCM:

    public class GcmIntentService extends IntentService {

        public GcmIntentService() {
            super("GcmIntentService");
        }

        @Override
        protected void onHandleIntent(Intent intent) {
            Bundle extras = intent.getExtras();
            GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(this);
            // The getMessageType() intent parameter must be the intent you received
            // in your BroadcastReceiver.
            String messageType = gcm.getMessageType(intent);

            if (extras != null && !extras.isEmpty()) {  // has effect of unparcelling Bundle
                // Since we're not using two way messaging, this is all we really to check for
                if (GoogleCloudMessaging.MESSAGE_TYPE_MESSAGE.equals(messageType)) {
                    Logger.getLogger("GCM_RECEIVED").log(Level.INFO, extras.toString());

                    showToast(extras.getString("message"));
                    Intent sendData = new Intent("chatupdater");
                    sendData.putExtra("msg",extras.getString("message"));
                    sendBroadcast(sendData);


                }
            }
   GcmBroadcastReceiver.completeWakefulIntent(intent);
        }

在onHandleIntent()方法I中广播的消息发送到被注册到一个片段BroadCastReceiver.I具有一个SlidingDrawerActivity和它有许多片段和ChatFragment是他们.我的一个想要从发送该消息GCMIntentService到ChatFragmen吨.

我的ChatFragment类:

public class ChatFragment extends Fragment {

    private EditText et_chat;
    Bundle mailData;
    String caller_mail;
    private ListView chatListview;
    private ChatWindowAdapter chatWindowAdapter;
    private List<ChatSession>PreviousChatSession;
    private List<ChatInfo> chatListItems;
    Button chat_send;
    public ChatFragment() {

    }

    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        getActivity().registerReceiver(new ChatBroadCastReceiver(),new IntentFilter("chatupdater"));

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.chat_window, null, false);
        et_chat = (EditText) v.findViewById(R.id.et_chat);
        chat_send = (Button) v.findViewById(R.id.bt_chat_send);
        chatListview = (ListView)v.findViewById(R.id.chat_listView);
        chatListItems = new ArrayList<ChatInfo>();
        chatWindowAdapter = new ChatWindowAdapter(getActivity(),chatListItems);
        chatListview.setAdapter(chatWindowAdapter);
        mailData=getArguments();
        caller_mail = mailData.getString(PropertyNames.Userinfo_Mail.getProperty());

        retrieveChats();

        chat_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ChatInfo chatInfo= new ChatInfo();
                chatInfo.setChat_text(et_chat.getText().toString());
                chatInfo.setDirection("right");
                chatListItems.add(chatInfo);
                chatWindowAdapter.notifyDataSetChanged();

                fetchID(caller_mail);
            }
        });

        return v;
    }

    private final BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
             String msg = intent.getStringExtra("msg");
             Toast.makeText(getActivity(),msg,Toast.LENGTH_LONG).show();
        }
    };

我用于chatFragment的ChatBroadCastReceiver类:

public class ChatBroadCastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {

    }
}  

我正在意图发送消息并在sendBroadcast(sendData)内部chatFragment和onReceive()方法中接收它我希望在Toast中看到消息.但Toast没有显示.
我是否为服务中的片段正确实现了BroadcastReceiver？

编辑:我已经调试,看到下面的部分没有调用

private final BroadcastReceiver receiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Log.i("chat","I am in BroadCastReceiver");
         String msg = intent.getStringExtra("msg");
         Toast.makeText(getActivity(),msg,Toast.LENGTH_LONG).show();
    }
};

我是否必须在接收器中包含任何内容？

Answer 1

在您的片段类中使用以下代码段:

注册广播:

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        getActivity().registerReceiver(this.broadCastNewMessage, new IntentFilter("bcNewMessage"));
        ...
    }

宣布你的广播:

BroadcastReceiver broadCastNewMessage = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
         // here you can update your db with new messages and update the ui (chat message list)
         msgAdapter.notifyDataSetChanged();
         mListView.requestLayout();
         ...
    }
}

3.取消注册您的广播:

@Override
    public void onDestroy() {
        super.onDestroy();
        getActivity().unregisterReceiver(broadCastNewMessage);
    }

然后在你的服务中调用sendBroadcast()方法:

this.sendBroadcast(new Intent().setAction("bcNewMessage"));

请享用!