Question

我尝试从当前类中删除listView中的项目后，从另一个片段类更新listView。例如，我删除了有费用的消费者，那么该消费者的费用也将被删除。但是消费者和费用是使用标签控件的不同页面，这是片段，当我删除消费者时，费用列表不会更新，直到我转到上一页，然后再次进入页面。当删除消费者列表中的消费者时，如何更新费用列表？我听说使用广播接收器能够做到这一点，但我怎么能在我的代码中实现它？我是android新手，请指导我。谢谢

以下是消费者/参与者列表的代码：

public class Participant extends ListFragment implements OnClickListener{

Intent intent;
TextView friendId;
Button addparticipant;
String eventId;
ListView lv;

public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    EventController controller = new EventController(getActivity());

    HashMap<String, String> queryValues = new HashMap<String, String>();
    Intent objIntent = getActivity().getIntent();
    eventId = objIntent.getStringExtra("eventId");
    queryValues.put("eventId", eventId);
    ArrayList<HashMap<String, String>> friendList = controller
            .getAllFriends(queryValues);
    if (friendList.size() != 0) {
        lv = getListView();
        lv.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                friendId = (TextView) view.findViewById(R.id.friendId);
                String valFriendId = friendId.getText().toString();
                Intent objIndent = new Intent(getActivity(),
                        EventPage.class);
                objIndent.putExtra("friendId", valFriendId);
                startActivity(objIndent);
            }
        });
        lv.setOnItemLongClickListener(new OnItemLongClickListener(){

            @Override
            public boolean onItemLongClick(AdapterView<?> arg0,
                    View arg1, int arg2, long arg3) {
                // TODO Auto-generated method stub
                friendId = (TextView) arg1.findViewById(R.id.friendId);
                registerForContextMenu(getListView());
                return false;
            }

        });
        SimpleAdapter adapter = new SimpleAdapter(getActivity(),
                friendList, R.layout.view_friend_entry, new String[] {
                        "friendId", "friendName", "friendSpending" },
                new int[] { R.id.friendId, R.id.friendName,
                        R.id.friendSpending });
        adapter.notifyDataSetChanged();
        setListAdapter(adapter);
    }
}

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.participant, container, false);
    addparticipant = (Button) rootView.findViewById(R.id.addpart);
    addparticipant.setOnClickListener(this);
    return rootView;

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    Intent objIntent = new Intent(getActivity(),
            AddParticipant.class);
    objIntent.putExtra("eventId", eventId);
    startActivity(objIntent);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
        ContextMenuInfo menuInfo) {
    String[] menuItems = getResources().getStringArray(R.array.menu);
    for (int i = 0; i < menuItems.length; i++) {
        menu.add(Menu.NONE, i, i, menuItems[i]);
    }
}

@Override
public boolean onContextItemSelected(MenuItem item) {
    int menuItemIndex = item.getItemId();
    EventController controller = new EventController(getActivity());
    switch (menuItemIndex) {
    case 0:
        String valFriendId = friendId.getText().toString();
        Intent objIndent = new Intent(getActivity(),
                EditParticipant.class);
        objIndent.putExtra("friendId", valFriendId);
        startActivity(objIndent);
        break;
    case 1:
        String valFriendId2 = friendId.getText().toString();
        controller.deleteFriend(valFriendId2);
        onResume();
    }

    return true;
}

@Override
public void onResume() {
    super.onResume();

    if (getListView() != null) {
        updateData();
    }
}

private void updateData() {
    EventController controller = new EventController(getActivity());
    HashMap<String, String> queryValues = new HashMap<String, String>();
    Intent objIntent = getActivity().getIntent();
    eventId = objIntent.getStringExtra("eventId");
    queryValues.put("eventId", eventId);
    SimpleAdapter adapter = new SimpleAdapter(getActivity(),
            controller.getAllFriends(queryValues),
            R.layout.view_friend_entry, new String[] { "friendId",
                    "friendName", "friendSpending" }, new int[] {
                    R.id.friendId, R.id.friendName, R.id.friendSpending });
    setListAdapter(adapter);
}

}

以下是费用清单的代码：

public class Expense extends ListFragment implements OnClickListener {

Button addexp;
TextView expenseId;
ListView lv;
String eventId, friendId;

public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    EventController controller = new EventController(getActivity());

    HashMap<String, String> queryValues = new HashMap<String, String>();
    Intent objIntent = getActivity().getIntent();
    eventId = objIntent.getStringExtra("eventId");
    queryValues.put("eventId", eventId);
    ArrayList<HashMap<String, String>> expenseList = controller
            .getAllExpenses(queryValues);
    if (expenseList.size() != 0) {
        lv = getListView();
        lv.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                expenseId = (TextView) view.findViewById(R.id.expenseId);
                String valExpenseId = expenseId.getText().toString();
                Intent objIndent = new Intent(getActivity(),
                        EditExpense.class);
                objIndent.putExtra("expenseId", valExpenseId);
                startActivity(objIndent);
            }
        });
        SimpleAdapter adapter = new SimpleAdapter(getActivity(),
                expenseList, R.layout.view_expense_entry, new String[] {
                        "expenseId", "expenseName","expenseQuantity" }, new int[] {
                        R.id.expenseId, R.id.expenseName, R.id.expenseQuantity });
        adapter.notifyDataSetChanged();
        setListAdapter(adapter);
    }
}

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.expense, container, false);
    addexp = (Button) rootView.findViewById(R.id.addexp);
    addexp.setOnClickListener(this);
    return rootView;

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    Intent objIntent = new Intent(getActivity(), AddExpense.class);
    objIntent.putExtra("eventId", eventId);
    startActivity(objIntent);
}

@Override
public void onResume() {
    super.onResume();

    if (getListView() != null) {
        updateData();
    }
}

private void updateData() {
    EventController controller = new EventController(getActivity());
    HashMap<String, String> queryValues = new HashMap<String, String>();
    Intent objIntent = getActivity().getIntent();
    eventId = objIntent.getStringExtra("eventId");
    queryValues.put("eventId", eventId);
    SimpleAdapter adapter = new SimpleAdapter(getActivity(),
            controller.getAllExpenses(queryValues),
            R.layout.view_expense_entry, new String[] { "expenseId",
                    "expenseName", "expenseQuantity" }, new int[] { R.id.expenseId,
                    R.id.expenseName, R.id.expenseQuantity });
    setListAdapter(adapter);
}

}

Answer 1

与我相同的情况，如果您使用FragmentPagerAdapter，请在FirstFragment

中尝试这样做

private void updateSecondFragment(){

    //Way to get TagName which generated by FragmentPagerAdapter
    String tagName = "android:switcher:" + R.id.pager + ":" + 1; // Your pager name & tab no of Second Fragment 

    //Get SecondFragment object from FirstFragment
    SecondFragment f2 = (SecondFragment)getActivity().getSupportFragmentManager().findFragmentByTag(tagName);

    //Then call your wish method from SecondFragment to update appropriate list
    f2.updateList();
}

我通过阅读this得到了这个想法。然后编辑一点！

Answer 2

一种方法是在包含两个片段的活动中创建方法，并从活动中访问片段方法。您可以使用相同的方法更新数据库并重新加载列表。

例如，在活动中

public void updateFragment2(){ ... }

在片段1中，您应该致电：

((ActivityClass)getActivity()).updateFragment2();

在“与活动通信”部分中，您可以看到此示例的说明： http://developer.android.com/guide/components/fragments.html

Android - 将ListView从片段更新到另一个片段

2 个答案: