我正在构建一个聊天应用程序，我有一个关于我的 fragment 的问题，该 fragment 包含一个包含所有聊天的 ListView 。

当用户收到一条消息时，聊天列表会更新(显示每次聊天的最后一条消息)(图片 1)。

当聊天不可见并且在该聊天中收到消息时，用户将收到通知(图片 2)

此时问题开始了。当用户单击通知时，聊天 ListView 似乎已损坏。当用户在点击通知后收到另一条消息时，他/她的手机会振动，但聊天 ListView 不会更改/更新。

其他 View 在点击通知后起作用。

下面是一段处理 ListView 更新的代码。

    protected PacketListener packetListener = new PacketListener() {

    @Override
    public void processPacket(Packet packet) {
        final Message message = (Message) packet;

        if (message.getBody() != null) {
            final String fromName = StringUtils.parseName(message.getFrom());

            runOnUiThread(new Runnable(){

                @Override
                public void run() {

                    Boolean seen = false;
                    if(ChatFragment.currentChat != null && ChatFragment.currentChat.getContact().getUsername().equals(fromName) && VisibilityHelper.appIsVisible() && VisibilityHelper.fragmentIsVisible(ChatFragment.fragmentClassName)) {
                        seen = true;
                    }

                    Long chat_id = chatsDataSource.getChatByContactId(contactsDataSource.getContactByUsername(fromName).getId()).getId();
                    ChatMessage newChatMessage = chatMessagesDataSource.insertChatMessage(chat_id, ConstantHelper.CHAT_MESSAGES_TYPE_RECEIVED, seen, DateHelper.getDatetime(), message.getBody());

                    Log.d("DEBUG", VisibilityHelper.sCurrentFragmentClassName);
                    if(VisibilityHelper.appIsVisible() && VisibilityHelper.fragmentIsVisible(ChatsFragment.fragmentClassName)) {
                        ChatsFragment chatsFragment = (ChatsFragment) getFragmentManager().findFragmentByTag(ChatsFragment.fragmentClassName);
                        Log.d("DEBUG", "REFRESHING");
                        chatsFragment.refreshChatsList();
                    }

                    if(!VisibilityHelper.appIsVisible()) {
                        notificationHelper.externalNotification(getBaseContext(), newChatMessage);
                    } else {
                        if(ChatFragment.currentChat != null && ChatFragment.currentChat.getContact().getUsername().equals(fromName) && VisibilityHelper.appIsVisible() && VisibilityHelper.fragmentIsVisible(ChatFragment.fragmentClassName)) {
                            ChatFragment.chatsList.add(newChatMessage);
                            ChatFragment.chatsList.notifyDataSetChanged();
                        } else {
                            notificationHelper.internalNotification(getBaseContext(), newChatMessage);
                        }
                    }
                }

            });
        }
    }

};

主要 Activity (如何创建 fragment )

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().requestFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setContentView(R.layout.activity_main);

    Bundle extras = getIntent().getExtras();

    initializeDataSources();
    setLastContactUpdate();

    if(usersDataSource.getCurrentUser() == null)
    {
        Intent LoginActivity = new Intent(getApplicationContext(), LoginActivity.class);
        LoginActivity.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(LoginActivity);
        finish();
    }
    else
    {
        if(localServiceBinder == null)
            localServiceBinder = new LocalServiceBinder();

        bindLocalService();

        runDispatchMethod(extras, savedInstanceState);

        if (savedInstanceState == null) {
            getAndSaveUserDetails();
            GCMRegistrationID = registerGCM();
        }
    }
}

protected void runDispatchMethod(Bundle extras, Bundle savedInstanceState) {
    if(savedInstanceState == null) {
        startFragment(new ChatsFragment(), false);
    }

    if(extras != null && extras.getString(ConstantHelper.RECEIVED_MESSAGES_FROM) != null && !extras.getString(ConstantHelper.RECEIVED_MESSAGES_FROM).equals("")) {
        getFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
        startFragment(new ChatsFragment(), false);

        ChatFragment chatFragment = new ChatFragment();
        Bundle chatExtras = (Bundle) new Bundle();
        chatExtras.putString(ConstantHelper.RECEIVED_MESSAGES_FROM, extras.getString(ConstantHelper.RECEIVED_MESSAGES_FROM));
        chatFragment.setArguments(chatExtras);
        startFragment(chatFragment);
        return;
    }
}

public void startFragment(Fragment newFragment) {
    startFragment(newFragment, true);
}

public void startFragment(Fragment newFragment, Boolean addToBackstack) {
    if(addToBackstack) {
        getFragmentManager().beginTransaction().replace(R.id.container, newFragment, newFragment.getClass().getName()).addToBackStack(newFragment.getClass().getName()).commit();
    } else {
        getFragmentManager().beginTransaction().replace(R.id.container, newFragment, newFragment.getClass().getName()).commit();
    }

    getFragmentManager().executePendingTransactions();
}

聊天适配器

public class ChatsAdapter extends BaseAdapter {

private List<Chat> chats;
private LayoutInflater inflater;
private String emptyLastMessageValue;

public ChatsAdapter(Context context, List<Chat> chats) {
    this.chats = chats;
    this.inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    emptyLastMessageValue = context.getText(R.string.fragment_chats_chat_created).toString();
}

@Override
public int getCount() {
    return chats.size();
}

@Override
public Chat getItem(int position) {
    return chats.get(position);
}

@Override
public long getItemId(int position) {
    return chats.get(position).getId();
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    View chatAdapterView = convertView;

    if(convertView == null)
        chatAdapterView = inflater.inflate(R.layout.adapter_chats, null);

    TextView layout_fullname = (TextView) chatAdapterView.findViewById(R.id.fullname);
    TextView layout_last_message = (TextView) chatAdapterView.findViewById(R.id.last_message);
    TextView layout_unread_messages = (TextView) chatAdapterView.findViewById(R.id.unread_messages);
    TextView layout_last_message_datetime = (TextView) chatAdapterView.findViewById(R.id.last_message_datetime);

    Chat row = chats.get(position);

    String firstname = row.getContact().getFirstname();
    String fullname = row.getContact().getFullname();

    if(firstname == null || firstname.equals(""))
        fullname = StringHelper.ucfirst(row.getContact().getUsername());

    layout_fullname.setText(fullname);

    String last_message_value;
    String last_message_datetime_value = "";
    if(row.getLastMessage() == null) {
        last_message_value = emptyLastMessageValue;
        layout_last_message_datetime.setVisibility(TextView.GONE);
        layout_unread_messages.setVisibility(TextView.GONE);
    } else {
        last_message_value = row.getLastMessage().getMessageBody();

        last_message_datetime_value = DateHelper.toReadableDatetime(row.getLastMessage().getMessageDatetime());
        layout_last_message_datetime.setText(last_message_datetime_value);

        Integer unreadMessages = row.getUnreadMessages();
        if(unreadMessages > 0) {
            layout_unread_messages.setText(String.valueOf(unreadMessages));
            layout_unread_messages.setVisibility(TextView.VISIBLE);
        } else {
            layout_unread_messages.setVisibility(TextView.GONE);
        }
    }

    layout_last_message.setText(last_message_value);

    return chatAdapterView;
}

}

刷新聊天列表功能

public void refreshChatsList() {
    Log.d("DEBUG", "It does come here!");
    chats.clear();
    chats.addAll(((MainActivity) getActivity()).chatsDataSource.getAllChats());
    chats_adapter.notifyDataSetChanged();
}

Logcat 输出

07-06 20:12:43.892: D/SMACK(14948): 08:12:43 PM RCV  (1106735848): <message id="3jRRg-24" to="tijme@192.168.137.1" type="chat" from="test@192.168.137.1/Smack"><body>Test</body></message>

07-06 20:12:43.962: D/DEBUG(14948): nl.test.messatch.fragments.ChatsFragment

07-06 20:12:43.962: D/DEBUG(14948): REFRESHING

07-06 20:12:43.962: D/DEBUG(14948): It does come here!

07-06 20:12:48.406: D/SMACK(14948): 08:12:48 PM RCV  (1106735848): <message id="3jRRg-25" to="tijme@192.168.137.1" type="chat" from="test@192.168.137.1/Smack"><body>Test 2</body></message>

07-06 20:12:48.446: D/DEBUG(14948): nl.test.messatch.fragments.ChatsFragment

07-06 20:12:51.059: D/KUTZOOI(14948): HELEMAAL WÄCK

07-06 20:12:51.099: D/dalvikvm(14948): GC_FOR_ALLOC freed 161K, 3% free 9653K/9912K, paused 19ms, total 21ms

07-06 20:12:51.109: I/dalvikvm-heap(14948): Grow heap (frag case) to 13.272MB for 4000016-byte allocation

07-06 20:12:51.139: D/dalvikvm(14948): GC_FOR_ALLOC freed 1K, 2% free 13558K/13820K, paused 25ms, total 25ms

07-06 20:12:54.953: D/SMACK(14948): 08:12:54 PM RCV  (1106735848): <message id="3jRRg-26" to="tijme@192.168.137.1" type="chat" from="test@192.168.137.1/Smack"><body>Test 3</body></message>

07-06 20:12:54.993: D/DEBUG(14948): nl.test.messatch.fragments.ChatsFragment

07-06 20:12:54.993: D/DEBUG(14948): REFRESHING

07-06 20:12:54.993: D/DEBUG(14948): It does come here!

聊天列表

通知

最佳答案

确保您在通过单击通知返回 Activity 后使用相同的 fragment (根据问题出现的方式判断)。如果您不持有对用户看到的同一实例的引用，那么任何聊天更新都将无提示地失败，因为您将只更新背景 fragment (而不是可见 fragment )。错误似乎出现在 runDispatchMethod() 中，您每次都在其中使用新 fragment 进行交易，而不是检查 ChatsFragment 的另一个实例是否已经可用(在这种情况下您只需在该实例上调用更新方法即可)。

关于java - 打开通知后 fragment 不会更新，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24598719/